304 Stainless Steel vs. 420 Stainless Steel：What's the Difference Between?

 

Choosing the right stainless steel grade is often a challenge for manufacturers, engineers, and designers. Selecting the wrong material can lead to premature rusting, mechanical failure, or increased production costs, especially for precision stainless steel CNC machined parts. Many projects require a balance of corrosion resistance, strength, and machinability—but understanding which stainless steel grade to choose can be confusing.

 

This is where the comparison between 304 stainless steel and 420 stainless steel becomes critical. 304 stainless steel is well-known for its excellent corrosion resistance and versatility, while 420 stainless steel stands out for its hardness and ability to be heat-treated for cutting and wear-resistant applications. If you need durable, reliable, and cost-effective components for your CNC machining services, knowing the differences will help you make the right decision.

 

304 stainless steel offers superior corrosion resistance and versatility, making it ideal for general industrial, food-grade, and architectural uses. 420 stainless steel provides higher hardness and wear resistance, ideal for cutting tools and blades. Choosing between them depends on your project’s needs for durability, corrosion protection, and machinability.

 

Understanding the differences between 304 stainless steel and 420 stainless steel is essential for selecting the right material for your CNC machining projects. In the sections below, we will cover their composition, mechanical properties, advantages and disadvantages, applications, and costs—giving you a complete guide to making an informed material choice for 304 stainless steel CNC machined parts or 420 stainless steel CNC machined parts.

 

 

 

 

 

Key Points

 

When comparing 304 stainless steel and 420 stainless steel, the choice depends on the balance of corrosion resistance, hardness, wear resistance, and cost required for your application.

 

304 stainless steel is an austenitic stainless steel with high chromium and nickel content, offering excellent corrosion resistance, durability, and formability. It is non-magnetic in annealed form, easy to weld, and widely used for food processing equipment, architectural structures, chemical storage tanks, and 304 stainless steel CNC machined parts. Its strength is moderate, and it cannot be hardened through heat treatment.

 

420 stainless steel, a martensitic stainless steel, is known for its high carbon content and ability to be hardened by heat treatment. It offers superior hardness and wear resistance, making it ideal for cutting tools, surgical instruments, and 420 stainless steel CNC machined parts. However, its corrosion resistance is lower than 304, and it is more prone to rust in wet or chemical environments without proper care.

 

In summary:

• Choose 304 stainless steel for projects requiring corrosion resistance, formability, and long-term durability.
  
• Choose 420 stainless steel for high-strength or cutting applications where wear resistance is the priority.
  
• 304 stainless steel is highly corrosion-resistant, easy to form and weld, making it ideal for applications like kitchen equipment, medical devices, and architectural components.
  
• 420 stainless steel offers superior hardness and wear resistance after heat treatment, making it suitable for cutting tools, surgical instruments, and parts requiring edge retention.
  
• 304 excels in environments where corrosion resistance and flexibility are priorities, while 420 is preferred where hardness and durability are critical.
  
• The choice between 304 and 420 depends on project requirements including mechanical stress, exposure to corrosive environments, and cost considerations.
  
• VMT provides expert CNC machining services for both 304 and 420 stainless steel, ensuring high-quality parts tailored to specific industry needs.

 

For the best results, consult professional CNC machining factories to match the material to your project’s environment, performance needs, and budget.

 

 

 

What is 304 Stainless Steel?

 

304 stainless steel is the most widely used austenitic stainless steel, valued for its excellent corrosion resistance, durability, and versatility in industrial and consumer applications. Composed primarily of iron, 18–20% chromium, and 8–10.5% nickel, it provides strong resistance to oxidation, chemicals, and general environmental exposure. It also contains small amounts of manganese, silicon, and carbon, which contribute to its mechanical properties and workability.

 

This stainless steel is non-magnetic in the annealed state, but it may become slightly magnetic after cold working. It cannot be hardened through heat treatment but can be strengthened by cold forming processes. Due to its excellent weldability and formability, 304 stainless steel is ideal for complex components and is a preferred material in CNC machining factories for creating high-quality 304 stainless steel CNC machined parts.

 

Typical applications include food processing equipment, kitchen appliances, chemical storage tanks, architectural panels, and piping systems. Its combination of corrosion resistance, ease of machining, and reasonable cost makes it a standard choice for industries requiring long-lasting and hygienic metal components.

 

In summary, 304 stainless steel is a versatile, corrosion-resistant material suitable for most environments, making it an excellent all-around choice for stainless steel CNC machined parts where strength, durability, and reliability are essential.

 

 

 

 

 

What is 420 Stainless Steel?

 

 

420 stainless steel is a high-carbon martensitic stainless steel known for its exceptional hardness, wear resistance, and ability to be heat-treated. Unlike austenitic grades like 304, 420 contains approximately 12–14% chromium and 0.15–0.40% carbon, with minimal nickel content. This composition allows it to achieve a much higher hardness when properly quenched and tempered, often exceeding 50 HRC, making it ideal for applications that require sharp edges and high durability.

 

420 stainless steel offers moderate corrosion resistance, performing well in dry environments and mild atmospheric conditions but requiring careful maintenance in wet or chemical-exposed settings. Compared to 304 stainless steel, it is more prone to rust if not properly treated or passivated.

 

In CNC machining, 420 stainless steel is widely used to manufacture industrial cutting tools, surgical instruments, bearings, and high-wear machine parts. Its ability to maintain sharpness and resist abrasion makes it a preferred choice for 420 stainless steel CNC machined parts where edge retention and mechanical strength are critical.

 

In summary, 420 stainless steel is the go-to material for high-hardness and wear-resistant applications. While it sacrifices some corrosion resistance compared to 304, its heat-treatable nature and mechanical strength make it indispensable for blades, tools, and precision industrial components.

 

 

 

 

 

Which is Better, 304 or 420 Stainless Steel?

 

Deciding whether 304 stainless steel or 420 stainless steel is better depends entirely on the specific requirements of your project. Each material excels in different areas, and their suitability is determined by factors such as corrosion resistance, hardness, wear resistance, and application environment.

 

304 stainless steel is generally considered better for corrosion resistance, formability, and long-term durability. It performs exceptionally well in wet, humid, or chemically exposed environments, making it the preferred choice for food processing equipment, architectural structures, and chemical storage applications. Additionally, it is easier to weld and machine, which makes 304 stainless steel CNC machined parts a cost-effective and reliable option for a wide range of industries.

 

420 stainless steel, on the other hand, is superior in hardness, edge retention, and wear resistance. It can be heat-treated to achieve high strength, making it the ideal material for blades, surgical instruments, industrial cutting tools, and 420 stainless steel CNC machined parts. However, it requires careful maintenance to avoid rusting in harsh or wet environments.

 

In short:

• Choose 304 stainless steel for projects requiring corrosion resistance, weldability, and durability.
• Choose 420 stainless steel for high-hardness applications like cutting tools and wear-resistant components.

 

Table: 304 vs. 420 Stainless Steel Comparison

 

 

 

 

This table gives readers a quick visual guide to decide which material is best for their stainless steel CNC machined parts and applications.

 

 

 

 

304 Stainless Steel vs. 420 Stainless Steel: Key Differences

 

When comparing 304 stainless steel and 420 stainless steel, it’s clear that each grade serves different purposes in manufacturing and CNC machining. 304 is an austenitic stainless steel designed for corrosion resistance and durability, while 420 is a martensitic stainless steel valued for its hardness and wear resistance. The key differences lie in their chemical composition, mechanical properties, machinability, and applications, which ultimately determine which material is best for your project.

 

Composition

• 304 stainless steel contains 18–20% chromium and 8–10.5% nickel, with low carbon content. This composition provides excellent corrosion resistance and stability in harsh environments.
  
• 420 stainless steel has 12–14% chromium, high carbon (0.15–0.40%), and minimal nickel, allowing it to be heat-treated to high hardness but with lower corrosion resistance.

 

Hardness

• 304 stainless steel has moderate hardness (around 70–90 HRB) and cannot be heat-treated.
  
• 420 stainless steel can achieve high hardness levels exceeding 50 HRC after heat treatment, making it ideal for blades, tools, and wear-resistant components.

 

Corrosion Resistance

• 304 is highly resistant to rust and chemical exposure, suitable for food processing, marine, and chemical industries.
  
• 420 has moderate corrosion resistance and can rust in wet or acidic environments without proper maintenance or passivation.

 

Wear Resistance

• 304 stainless steel offers moderate wear resistance, sufficient for structural and non-cutting components.
  
• 420 stainless steel excels in wear resistance due to its hardness, making it ideal for knives, scissors, and industrial cutting tools.

 

Oxidation Resistance

• Both grades resist oxidation at moderate temperatures, but 304 performs better under continuous exposure to heat or chemicals, whereas 420 can discolor or scale faster at high temperatures.

 

Welding

• 304 stainless steel is easy to weld using standard techniques, ideal for CNC machined assemblies.
  
• 420 stainless steel is more challenging to weld due to its high carbon content and tendency to form cracks if not preheated or post-heat-treated.

 

Heat Resistance

• 304 can withstand continuous exposure up to ~870°C (1600°F) without losing corrosion resistance.
  
• 420 has lower heat resistance and can lose hardness or corrode faster under prolonged high temperatures.

 

Machinability

• 304 stainless steel has good machinability in annealed form, widely used for 304 stainless steel CNC machined parts.
  
• 420 stainless steel is harder to machine, especially after hardening, and requires more advanced tooling in CNC machining services.

 

Cost

• 304 stainless steel is moderately priced, cost-effective for most industrial and consumer projects.
  
• 420 stainless steel can be slightly higher in cost due to heat treatment requirements and machining tool wear.

 

Applications

• 304 stainless steel: Food processing equipment, architectural components, chemical tanks, piping, and general CNC machined parts.
• 420 stainless steel: Industrial blades, cutting tools, surgical instruments, bearings, and high-wear CNC machined parts.

 

Table: Key Differences Between 304 and 420 Stainless Steel

 

 

 

This table allows readers to quickly evaluate which stainless steel grade suits their project and aligns perfectly with SEO for 304 stainless steel CNC machined parts and 420 stainless steel CNC machined parts.

 

 

 

 

304 Stainless Steel vs. 420 Stainless Steel: Advantages and Disadvantages

 

 

Understanding the advantages and disadvantages of 304 stainless steel and 420 stainless steel is crucial for selecting the right material for your project. Both grades serve different purposes: 304 excels in corrosion resistance and durability, while 420 stands out for hardness and wear resistance. Evaluating their strengths and weaknesses will help you decide which is best for your stainless steel CNC machined parts.

 

 

 

 

304 Stainless Steel: Advantages and Disadvantages

 

304 stainless steel is one of the most versatile and widely used stainless steels, particularly in industries that require corrosion-resistant, hygienic, and formable materials. However, it does have certain limitations that need to be considered for applications requiring high hardness or heavy wear resistance.

 

Advantages of 304 Stainless Steel

• Excellent corrosion resistance in wet, humid, and chemical environments.
• Good formability and weldability, making it ideal for complex CNC machined parts.
• Non-magnetic in annealed state, suitable for sensitive applications.
• Widely available and cost-effective for general industrial and consumer use.
• High durability and low maintenance for long-term applications.

 

Disadvantages of 304 Stainless Steel

• Cannot be heat-treated for increased hardness.
• Moderate wear resistance, unsuitable for cutting tools or high-friction parts.
• Higher initial cost than plain carbon steels.

 

 

420 Stainless Steel: Advantages and Disadvantages

 

420 stainless steel is a high-carbon martensitic stainless steel known for exceptional hardness, edge retention, and wear resistance. Its unique properties make it the material of choice for blades, surgical instruments, and industrial cutting tools, though it requires more maintenance in corrosive environments.

 

Advantages of 420 Stainless Steel

• High hardness (up to 50 HRC or higher after heat treatment).
• Excellent wear and abrasion resistance, ideal for blades and cutting tools.
• Heat-treatable, allowing customization of hardness for specific applications.
• Good machinability when annealed, suitable for precise CNC parts.

 

Disadvantages of 420 Stainless Steel

• Lower corrosion resistance than 304, prone to rust in wet or chemical environments.
• More difficult to weld due to high carbon content.
• Requires careful maintenance and passivation to prevent oxidation.
• More challenging to machine after hardening, increasing tool wear in CNC machining.

 

Table: Advantages and Disadvantages of 304 vs. 420 Stainless Steel

 

 

 

This table allows readers to quickly compare the strengths and weaknesses of both stainless steels and understand which is better for their CNC machining services and applications.

 

 

 

 

 

304 Stainless Steel vs. 420 Stainless Steel: Property Comparison

 

 

Understanding the chemical composition of stainless steel grades 304 and 420 is essential for recognizing their performance characteristics and suitability for various applications. Chemical elements like carbon, chromium, nickel, and others significantly influence corrosion resistance, hardness, machinability, and other key properties. This section compares the detailed chemical makeup of 304 and 420 stainless steels to highlight the differences driving their unique advantages.

 

 

 

304 Stainless Steel vs. 420 Stainless Steel: Chemical Composition

 

 

 

 

This chemical composition comparison explains why 304 stainless steel excels in corrosion resistance and formability, while 420 stainless steel is better suited for applications demanding high hardness and wear resistance due to its higher carbon and lower nickel content.

 

 

 

304 Stainless Steel and 420 Stainless Steel: Physical Properties

 

Physical properties significantly impact how stainless steel performs in manufacturing, CNC machining, and real-world applications. Factors like density, melting point, thermal conductivity, and corrosion resistance determine the material’s behavior under different conditions. This section compares the key physical properties of 304 stainless steel and 420 stainless steel, helping readers understand their suitability for various environments and machining processes.

 

Density

 

Both 304 and 420 stainless steels have similar densities, typically around 7.9 to 8.0 g/cm³. This density makes them relatively heavy compared to aluminum or titanium but typical for stainless steels, providing strength and durability for structural and mechanical parts.

 

 

Melting Point (°C)

 

The melting point of 304 stainless steel ranges between 1400°C to 1450°C, while 420 stainless steel melts slightly lower, generally around 1425°C. These high melting points ensure that both materials maintain structural integrity under high-temperature manufacturing processes like welding or heat treatment.

 

 

Thermal Conductivity (W/mK)

 

304 stainless steel has a thermal conductivity of about 16.2 W/mK, higher than 420 stainless steel’s 20 W/mK. This property affects heat dissipation during machining or in-service use, with 304 stainless steel slightly better at conducting heat, useful in heat exchangers or cooking equipment.

 

 

Resistivity (Ω.m)

 

The electrical resistivity of 304 stainless steel is approximately 7.2 × 10⁻⁷ Ω·m, and 420 stainless steel is slightly higher, around 8.0 × 10⁻⁷ Ω·m. These values mean both are relatively poor conductors of electricity compared to copper but typical for stainless steel grades.

 

 

Thermal Expansion

 

The linear thermal expansion coefficient measures how much the material expands with temperature changes. 304 stainless steel has a coefficient of about 17.2 × 10⁻⁶ /K, whereas 420 stainless steel’s is slightly lower at 10.4 × 10⁻⁶ /K. This difference affects dimensional stability in heated environments, with 420 stainless steel offering better stability under thermal stress.

 

 

Corrosion Resistance

 

304 stainless steel offers excellent corrosion resistance, especially in acidic or chloride-rich environments. In contrast, 420 stainless steel’s corrosion resistance is moderate, requiring additional surface treatment or maintenance to prevent rust in moist or harsh chemical conditions.

 

 

Magnetic Properties

 

In the annealed state, 304 stainless steel is generally non-magnetic due to its austenitic structure but may become slightly magnetic when cold worked. 420 stainless steel is magnetic because of its martensitic crystal structure, important for applications where magnetic properties are a concern.

 

 

Formability

 

304 stainless steel exhibits high formability and ductility, allowing it to be easily shaped into complex parts without cracking. 420 stainless steel is less formable due to its higher carbon content and hardness, making it more suitable for machining than forming.

 

 

Machinability (Annealing)

 

Both materials can be machined, but 304 stainless steel has better machinability in the annealed state, offering easier cutting and shaping during CNC machining. 420 stainless steel is machinable before hardening but becomes challenging afterward due to increased hardness.

 

 

Environmental Adaptability

 

304 stainless steel’s superior corrosion resistance allows it to thrive in harsh and humid environments, such as food processing or chemical plants. 420 stainless steel is better suited for dry or controlled environments where wear resistance is critical but corrosion exposure is minimal.

 

 

Table: Physical Properties Comparison of 304 vs. 420 Stainless Steel

 

 

 

 

This table gives readers a quick overview to understand how the two stainless steels differ physically, helping guide decisions for stainless steel CNC machined parts and related applications.

 

 

 

 

304 Stainless Steel and 420 Stainless Steel: Mechanical Properties

 

 

Mechanical properties are critical to understanding how stainless steels perform under stress, impact, and deformation during service and machining. Comparing 304 stainless steel and 420 stainless steel across metrics like hardness, tensile strength, ductility, and elastic modulus reveals their functional differences and helps guide material selection for CNC machined parts and other precision applications.

 

Hardness (HRC)

• 304 stainless steel typically has a hardness of about 70–90 HRB (Rockwell B scale), equivalent to roughly 15–25 HRC (Rockwell C scale). It cannot be heat-treated to increase hardness.
  
• 420 stainless steel achieves much higher hardness, generally up to 50+ HRC after heat treatment, making it ideal for cutting tools and wear-resistant parts.

 

Hardness (HV)

• Vickers hardness (HV) values for 304 stainless steel range from 150 to 210 HV, reflecting moderate hardness suitable for structural parts.
  
• 420 stainless steel exhibits hardness values between 450 to 600 HV post heat treatment, indicating superior wear resistance.

 

Hardness: HRC/HRB

• As noted, 304 falls in the 70–90 HRB range, soft compared to 420, which can reach 50+ HRC after proper heat treatment.

 

Tensile Strength (MPa)

• 304 stainless steel has an ultimate tensile strength of around 520–750 MPa, offering good strength and flexibility.
  
• 420 stainless steel’s tensile strength is higher, approximately 655–900 MPa, thanks to its hardened structure.

 

Elongation (Rp0.2/MPa) and Ductility (%)

• 304 stainless steel displays excellent ductility, with elongation at break around 40–60%, enabling it to deform significantly without breaking.
  
• 420 stainless steel has lower ductility, usually between 10–20%, due to its hardened nature.

 

Ultimate Tensile Strength and Yield Tensile Strength

• 304 stainless steel’s yield strength ranges between 215–505 MPa, with ultimate tensile strength reaching up to 750 MPa.
  
• 420 stainless steel’s yield strength is higher, generally around 275–520 MPa, with ultimate tensile strength up to 900 MPa.

 

Reduction of Area (Z/%)

• 304 stainless steel typically shows a reduction of area over 50%, indicating good ductility.
  
• 420 stainless steel has a smaller reduction of area, around 20–30%, reflecting its brittleness after hardening.

 

Heating Temperature

• 304 stainless steel is stable up to around 870°C without loss of corrosion resistance.
  
• 420 stainless steel’s heat treatment ranges between 980°C to 1050°C, necessary for hardening.

 

Elastic Modulus (Young's Modulus), GPa

 

Both materials have similar elastic moduli:

• 304 stainless steel: approximately 193–200 GPa
• 420 stainless steel: approximately 190–210 GPa

 

Elongation at Break (%)

• 304 stainless steel can stretch between 40–60% before breaking.
  
• 420 stainless steel typically elongates between 10–20%, much less ductile.

 

Fatigue Strength (MPa)

• Fatigue strength of 304 stainless steel is around 240–300 MPa, suitable for cyclic loading.
  
• 420 stainless steel’s fatigue strength varies widely but generally lower due to brittleness.

 

Shear Strength (MPa)

• 304 stainless steel has shear strength approximately 310–400 MPa.
  
• 420 stainless steel shear strength can exceed 500 MPa post heat treatment.

 

Shear Modulus, GPa

• The shear modulus for both grades is similar, around 75–85 GPa.

 

Poisson’s Ratio

• Both steels have a Poisson’s ratio near 0.27–0.30, typical for stainless steels.

 

Area Reduction

• 304 stainless steel exhibits a higher reduction of area, meaning better plastic deformation capacity, compared to 420 stainless steel, which is less ductile.

 

 

Table: Mechanical Properties Comparison of 304 vs. 420 Stainless Steel

 

 

 

 

This table offers a clear and quick reference to understand the mechanical performance differences between 304 and 420 stainless steels, assisting in selecting the right material for CNC machining services and specific application needs.

 

 

 

 

304 and 420 Stainless Steel: Heat Treatment

 

 

Heat treatment is a vital process that influences the mechanical properties, corrosion resistance, and machinability of stainless steels. While 304 stainless steel generally cannot be hardened by heat treatment due to its austenitic structure, 420 stainless steel is highly responsive to heat treatment processes, which significantly improve its hardness and wear resistance. Understanding these differences is crucial for selecting the appropriate grade and treatment process for CNC machining and application requirements.

 

 

 

 

Heat Treatment of 304 Stainless Steel

 

304 stainless steel is an austenitic stainless steel, meaning it has a face-centered cubic crystal structure that remains stable at room temperature. This structure cannot be hardened by conventional heat treatment methods like quenching and tempering. Instead, 304 stainless steel typically undergoes solution annealing, which involves heating to about 1010°C to 1120°C followed by rapid cooling (usually water quenching).

 

This process dissolves carbides and homogenizes the microstructure, restoring corrosion resistance and ductility after welding or cold working. While solution annealing improves corrosion resistance and relieves internal stresses, it does not significantly increase hardness or strength.

 

 

Heat Treatment of 420 Stainless Steel

 

420 stainless steel, a martensitic stainless steel, contains higher carbon content and can be hardened by heat treatment. The typical heat treatment process involves:

• Austenitizing: Heating the steel to around 980°C to 1050°C to transform the microstructure into austenite.
• Quenching: Rapid cooling, usually in oil or air, to form hard martensite.
• Tempering: Reheating at a lower temperature (150°C to 370°C) to adjust hardness and relieve brittleness.

Through this heat treatment cycle, 420 stainless steel can achieve high hardness levels (up to 50+ HRC), improved wear resistance, and enhanced mechanical strength, making it ideal for cutting tools, surgical instruments, and wear-prone CNC machined parts.

 

However, improper heat treatment can lead to reduced corrosion resistance and increased brittleness, so precise control of temperature and cooling rates is essential.

 

Understanding the heat treatment characteristics of both grades is fundamental for engineers and manufacturers to optimize performance and longevity of 304 stainless steel CNC machined parts and 420 stainless steel CNC machined parts.

 

 

Table: Heat Treatment Comparison of 304 vs. 420 Stainless Steel

 

 

 

 

 

This table offers a concise overview of how heat treatment differs for these two stainless steel grades, helping readers make informed decisions for CNC machining services and part applications.

 

 

 

 

 

304 and 420 Stainless Steel: Applications and Uses

 

 

304 and 420 stainless steels serve distinct roles across various industries due to their differing properties. While 304 stainless steel excels in corrosion resistance and formability, making it ideal for environments demanding hygiene and durability, 420 stainless steel is prized for its hardness and wear resistance, suitable for cutting tools and precision components. Understanding their applications helps manufacturers and engineers select the right stainless steel grade for specific CNC machining parts and industrial uses.

 

 

 

 

 

Kitchen Equipment and Food Processing

 

304 stainless steel is widely used in kitchen environments and food processing due to its excellent corrosion resistance and easy cleaning. Common applications include sinks, countertops, dishwashers, refrigerators, blenders, conveyor belts, and storage tanks. These components benefit from 304’s resistance to acids and food-grade safety. Conversely, 420 stainless steel is less common here but may be used in sharp cutting tools within the food industry due to its hardness.

 

 

Medical and Pharmaceutical Equipment

 

304 stainless steel’s biocompatibility and resistance to corrosion make it suitable for surgical instruments, medical devices, sterilization trays, and pharmaceutical processing equipment. Meanwhile, 420 stainless steel is favored for surgical blades, scalpels, scissors, needle holders, and other instruments where edge retention and hardness are critical for precision cutting.

 

 

Chemical and Petrochemical Industries

 

304 stainless steel performs well in chemical storage tanks, heat exchangers, piping systems, and reactors due to its chemical resistance. However, 420 stainless steel is generally less used in these corrosive environments but may be applied in wear-resistant components where mechanical strength is prioritized.

 

 

Architectural and Structural Applications

 

304 stainless steel’s aesthetic appeal and corrosion resistance suit it for building facades, handrails, railings, elevator panels, and decorative strips. Its formability allows for diverse architectural designs. 420 stainless steel, with its high hardness, is rarely used in these applications.

 

 

Tableware and Kitchenware

 

304 stainless steel is commonly used in tableware, kitchen knives, scissors, cutting tools, and blades that require resistance to staining and rust. For high-end cutting tools demanding superior edge retention, 420 stainless steel’s hardness and heat treatability make it the preferred choice.

 

 

Industrial Blades and Cutting Tools

 

420 stainless steel dominates this sector with applications including industrial blades, cutting tools, shear blades, and machine knives. Its ability to be hardened makes it ideal for wear resistance in demanding industrial environments.

 

 

Surgical Instruments

 

In surgical instruments, 420 stainless steel is preferred for tools requiring sharp, durable edges like scalpels, scissors, needle holders, and pliers, while 304 stainless steel is used where corrosion resistance and flexibility are prioritized.

 

 

Bearings and Valve Components

 

304 stainless steel is often used in ball bearings, roller bearings, valve seats, and valve stems where corrosion resistance and toughness are essential. 420 stainless steel may be selected for components requiring greater hardness.

 

 

Automotive and Aerospace Components

 

Both grades find applications in this industry. 304 stainless steel is used for engine components, gear shafts, fuel injector parts, and aerospace fasteners due to its corrosion resistance and mechanical strength. 420 stainless steel is employed where high hardness and wear resistance are crucial, especially in cutting and precision parts.

 

 

This overview highlights how 304 stainless steel CNC machined parts and 420 stainless steel CNC machined parts are tailored for specific industries and applications, emphasizing the importance of choosing the right material for optimal performance.

 

 

Table: Applications and Uses of 304 vs. 420 Stainless Steel

 

 

 

 

This table provides a quick reference to understand the typical applications where 304 stainless steel CNC machined parts and 420 stainless steel CNC machined parts are preferred, helping guide material selection for CNC machining services.

 

 

 

 

304 Stainless Steel vs. 420 Stainless Steel: Cost and Price

 

 

Cost is a key factor when selecting stainless steel grades for CNC machined parts, impacting both project budgets and long-term value. Understanding the initial expenses, processing costs, and lifecycle benefits of 304 stainless steel and 420 stainless steel helps manufacturers and buyers make informed decisions. Although 420 stainless steel often has a higher upfront cost due to heat treatment and alloying elements, the total cost-effectiveness depends on the application and performance requirements.

 

 

Initial Cost Comparison

 

Generally, 304 stainless steel is more widely produced and used, making it more readily available and often less expensive upfront than 420 stainless steel. Its austenitic structure requires less specialized processing, contributing to lower raw material costs.

 

In contrast, 420 stainless steel contains higher carbon and chromium content and demands heat treatment processes, increasing its initial price. The specialized manufacturing steps and lower production volumes can lead to a higher market cost per kilogram or unit.

 

 

Long-Term Cost Benefits

 

Although 420 stainless steel typically costs more initially, its superior hardness, wear resistance, and durability can reduce replacement frequency and maintenance costs over time. For parts subject to high wear or cutting applications, investing in 420 stainless steel CNC machined parts may offer better value due to longer service life.

 

On the other hand, 304 stainless steel, with its excellent corrosion resistance and formability, offers long-term savings in environments where corrosion or chemical exposure is the primary concern, avoiding costs associated with rust damage and repairs.

 

 

Processing Costs

• 304 stainless steel is generally easier to machine and weld, resulting in lower manufacturing and CNC machining service costs. Its ductility allows for more efficient forming and shaping with less tool wear.
• 420 stainless steel is harder and less ductile, which increases machining difficulty and tool wear, raising processing costs. Heat treatment steps also add to the overall manufacturing expenses, especially when tight tolerances and surface finishes are required.

 

 

Market Price

 

Market prices fluctuate based on supply, demand, and global metal markets. Typically, 304 stainless steel commands a lower price than 420 stainless steel due to broader availability and lower alloy content. However, prices for both grades may vary depending on geopolitical factors and raw material costs.

 

Choosing between 304 and 420 stainless steel for CNC machined parts involves balancing upfront costs with performance requirements. VMT CNC machining services can help optimize material selection to meet budget and quality goals effectively.

 

 

Table: Cost and Price Comparison of 304 vs. 420 Stainless Steel

 

 

 

 

This table provides a quick overview to help readers understand cost considerations for 304 stainless steel CNC machined parts versus 420 stainless steel CNC machined parts.

 

 

 

304 Stainless Steel vs. 420 Stainless Steel: National Standards and Equivalent Grades

 

 

Understanding the national standards and equivalent grades for stainless steel is essential for selecting the right material that meets regulatory, quality, and performance requirements. Both 304 stainless steel and 420 stainless steel have well-established standards across various countries and organizations, ensuring consistency and reliability for CNC machined parts and industrial applications.

 

 

304 Stainless Steel: Standards and Equivalents

 

AISI/ASTM (American Iron and Steel Institute / American Society for Testing and Materials):

• Commonly designated as 304 or 304L (low carbon version for improved weldability).

EN (European Norm):

• Equivalent grade: 1.4301 (304), 1.4307 (304L).

JIS (Japanese Industrial Standards):

• Equivalent grade: SUS304.

GB (Chinese National Standard):

• Equivalent grade: 0Cr18Ni9.

DIN (German Institute for Standardization):

• Equivalent grade: X5CrNi18-10.

These standards specify chemical composition limits, mechanical properties, and testing methods to ensure material quality and performance.

 

 

420 Stainless Steel: Standards and Equivalents

 

AISI/ASTM:

• Commonly known as 420 or 420A, 420B, 420C depending on carbon content and application.

EN:

• Equivalent grades include 1.4021 (420A), 1.4028 (420B), and 1.4034 (420C).

JIS:

• Equivalent grade: SUS420J1, SUS420J2.

GB:

• Equivalent grade: 0Cr13.

DIN:

• Equivalent grades: X20Cr13, X30Cr13.

These grades differ slightly in carbon content and properties, offering options for tailored hardness and corrosion resistance requirements.

 

 

Importance for CNC Machining and Industry

 

Adhering to recognized standards guarantees that 304 stainless steel CNC machined parts and 420 stainless steel CNC machined parts meet expected mechanical and chemical properties, ensuring compatibility and safety in critical applications. It also facilitates international trade and compliance with regulatory bodies.

 

 

Table: National Standards and Equivalent Grades for 304 vs. 420 Stainless Steel

 

 

 

This table helps clarify international equivalents of 304 and 420 stainless steel, useful for sourcing and specification in CNC machining factories and manufacturing.

 

 

 

 

 

How to Choose Between 304 and 420 Stainless Steel?

 

 

Choosing between 304 stainless steel and 420 stainless steel depends largely on the specific requirements of your project, including environmental conditions, mechanical stresses, and desired properties such as corrosion resistance, hardness, and machinability. Understanding the strengths and limitations of each grade allows engineers and manufacturers to select the most suitable material for their CNC machined parts and applications.

 

 

When Should I Use 304 Stainless Steel?

 

304 stainless steel is an excellent choice when corrosion resistance and formability are primary concerns. It is ideal for environments exposed to moisture, chemicals, or food products, such as kitchen equipment, food processing machinery, and chemical storage tanks. Its austenitic structure provides good toughness and ductility, making it suitable for complex shapes and welding.

 

Use 304 stainless steel for applications requiring moderate mechanical strength but high resistance to rust and staining, including architectural components, medical equipment, and general-purpose industrial parts. It is also cost-effective for projects where corrosion resistance outweighs the need for extreme hardness.

 

 

When Should I Use 420 Stainless Steel?

 

420 stainless steel should be selected when high hardness, wear resistance, and the ability to hold a sharp edge are essential. This grade is commonly used in cutting tools, surgical instruments, knives, and components subject to significant mechanical wear. Its martensitic structure allows for heat treatment that can dramatically increase hardness and strength, though at the expense of corrosion resistance and ductility.

 

Choose 420 stainless steel for applications where durability and edge retention are critical, but the environment is less corrosive or where protective coatings or maintenance can mitigate rust risk. It is also suitable for parts requiring precision machining and high surface finish, such as valve components and industrial blades.

 

This guidance helps optimize material selection for various CNC machining services and ensures parts meet performance, durability, and cost objectives effectively.

 

 

Table: How to Choose Between 304 and 420 Stainless Steel

 

 

 

 

This table provides an at-a-glance guide to help decide the best stainless steel grade for your CNC machining parts based on project requirements.

 

 

 

 

 

Are 304 Stainless Steel and 420 Stainless Steel Suitable for Your Project?

 

 

Selecting the right stainless steel grade for a project hinges on understanding the material properties and matching them with the specific needs of the application. Both 304 stainless steel and 420 stainless steel offer distinct advantages that make them suitable for different types of CNC machined parts and industrial uses.

 

304 stainless steel is highly suitable for projects that demand excellent corrosion resistance, good formability, and moderate mechanical strength. If your project involves exposure to moisture, chemicals, or food contact—such as kitchen equipment, medical devices, or architectural components—304 stainless steel is likely the best fit. Its ease of welding and shaping also makes it ideal for complex designs requiring precise fabrication.

 

On the other hand, 420 stainless steel is better suited for applications where hardness, wear resistance, and edge retention are paramount. Projects involving cutting tools, surgical instruments, or components subjected to high mechanical stress will benefit from 420’s superior hardness after heat treatment. However, it is less resistant to corrosion, so it’s best used in less aggressive environments or where maintenance and coatings can help prevent rust.

 

In summary, understanding your project’s environmental conditions, mechanical demands, and performance priorities is crucial. Choosing the right stainless steel grade not only ensures the durability and functionality of the CNC machined parts but also optimizes cost and efficiency.

 

VMT’s CNC machining factory offers expertise in producing high-quality 304 stainless steel CNC machined parts and 420 stainless steel CNC machined parts, helping clients select and manufacture materials that best suit their project requirements.

 

 

 

 

VMT: How Can We Provide You With Stainless Steel CNC Machined Parts?

 

 

VMT is a leading CNC machining factory specializing in high-precision stainless steel machining services. With years of experience working with various stainless steel grades, including 304 stainless steel and 420 stainless steel, VMT offers tailored solutions to meet the specific needs of diverse industries.

 

Expertise in Material Selection

 

Our engineering team helps clients choose the optimal stainless steel grade based on project requirements, balancing factors such as corrosion resistance, hardness, machinability, and cost. Whether your project demands the excellent corrosion resistance of 304 stainless steel or the superior hardness of 420 stainless steel, VMT provides expert guidance to ensure the best fit.

 

Advanced CNC Machining Services

 

VMT is equipped with state-of-the-art CNC machinery capable of producing complex and precise components from both 304 and 420 stainless steel. Our machining processes are optimized to handle the unique characteristics of each stainless steel grade, ensuring dimensional accuracy, surface finish quality, and tight tolerances.

 

Quality Control and Assurance

 

Quality is at the heart of our operations. VMT implements rigorous inspection protocols throughout the manufacturing process, from raw material verification to final product testing. This ensures that every stainless steel CNC machined part meets or exceeds industry standards and customer specifications.

 

Customization and Flexibility

 

We accommodate small to large batch production runs, offering flexibility for prototype development, pilot production, and full-scale manufacturing. Our customization capabilities allow us to produce parts tailored precisely to your design and functional requirements.

 

Timely Delivery and Competitive Pricing

 

VMT understands the importance of project timelines and budget constraints. We strive to deliver high-quality stainless steel CNC machined parts on schedule, providing competitive pricing without compromising quality or service.

 

By partnering with VMT, customers gain access to comprehensive CNC machining services for stainless steel parts, backed by technical expertise, advanced equipment, and a commitment to excellence.

 

 

 

Conclusion

 

Choosing between 304 stainless steel and 420 stainless steel depends on the specific demands of your project, including environmental exposure, mechanical requirements, and budget considerations. 304 stainless steel excels in corrosion resistance, formability, and versatility, making it ideal for applications in food processing, medical equipment, and architectural components. In contrast, 420 stainless steel offers superior hardness and wear resistance after heat treatment, making it the preferred choice for cutting tools, surgical instruments, and other applications requiring high durability and edge retention.

 

Understanding the key differences in composition, mechanical properties, corrosion resistance, and cost helps manufacturers and designers select the most suitable stainless steel grade for their CNC machined parts. VMT’s advanced CNC machining services and material expertise ensure precise, high-quality production of both 304 stainless steel CNC machined parts and 420 stainless steel CNC machined parts, tailored to meet the diverse needs of various industries.

 

By aligning material selection with project goals, users can optimize performance, longevity, and cost-effectiveness, benefiting from the unique advantages of each stainless steel grade. Whether prioritizing corrosion resistance or hardness, VMT provides comprehensive support from material consultation to finished part delivery, making it a reliable partner for stainless steel CNC machining solutions.

 

 

 

 

 

 

Frequently Asked Questions (FAQs)

 

 

1. Can 304 stainless steel be hardened as well as 420 stainless steel?

 

No, 304 stainless steel is an austenitic grade that cannot be significantly hardened by heat treatment. In contrast, 420 stainless steel is martensitic and can be heat treated to achieve high hardness and wear resistance.

 

 

2. Is 304 stainless steel better than 400 stainless steel?

 

It depends on the application. 304 offers superior corrosion resistance and formability, while 400-series stainless steels (including 420) generally provide higher hardness and wear resistance but lower corrosion resistance.

 

 

3. Which is better, 304 stainless steel or 410 stainless steel?

 

304 stainless steel is better for corrosion resistance and forming applications, while 410 stainless steel is preferred for applications needing higher hardness and moderate corrosion resistance.

 

 

4. Is 420 stainless steel of good quality?

 

Yes, 420 stainless steel is considered high-quality for applications requiring excellent hardness, wear resistance, and the ability to maintain a sharp edge.

 

 

5. Is 304 stainless steel of good quality?

 

Yes, 304 stainless steel is widely regarded for its excellent corrosion resistance, durability, and versatility in various industries.

 

 

6. Does 420 stainless steel rust?

 

420 stainless steel is more prone to rust compared to 304 because of its lower corrosion resistance, especially if not properly maintained or coated.

 

 

7. Which is better, 304 stainless steel or 430 stainless steel?

 

304 stainless steel has better corrosion resistance and is more versatile, while 430 is ferritic with moderate corrosion resistance and is often used for decorative purposes.

 

 

8. Does SUS304 stainless steel rust?

 

SUS304 is highly corrosion-resistant but can rust under harsh conditions or without proper care.

 

 

9. Which is better, 304 stainless steel or 430 stainless steel?

 

(Repeat question) 304 stainless steel generally outperforms 430 in corrosion resistance and mechanical properties.

 

 

10. Which is better, 316 stainless steel or 420 stainless steel?

 

316 stainless steel offers superior corrosion resistance, especially against chlorides, while 420 stainless steel is harder and better for cutting tools and wear resistance.

 

 

11. Does 304 stainless steel rust?

 

304 stainless steel is resistant to rust but can corrode in very aggressive environments or if exposed to chloride ions for extended periods.

 

 

12. What grade is 420 stainless steel?

 

420 stainless steel is a martensitic stainless steel known for its high carbon content, hardness, and wear resistance.

 

 

13. Is 420 stainless steel safe for the food industry?

 

Yes, 420 stainless steel is used in food industry applications such as cutlery and surgical instruments, but it requires proper cleaning and maintenance due to its lower corrosion resistance compared to 304.

 

 

14. What is the difference between 440C and 304 stainless steel?

 

440C stainless steel has a higher carbon content, offering superior hardness and wear resistance for cutting tools, while 304 is more corrosion resistant and versatile.

 

 

15. What is the difference between 401 and 304 stainless steel?

 

401 stainless steel is a ferritic grade with moderate corrosion resistance and higher strength, whereas 304 is austenitic with excellent corrosion resistance and better formability.

 

 

16. Is 420 stainless steel or 440 stainless steel better?

 

440 stainless steel generally offers higher hardness and wear resistance compared to 420, making it better for demanding cutting and wear applications.