Comparison of stainless steel 420 and 304

2025-03-28

The difference between 420 stainless steel and 304 stainless steel is that 420 has higher hardness and wear resistance than 304. 420 is a martensitic steel, but it does not have high chemical resistance like 300 wire. It will rust when it comes into contact with strong chemicals. It is magnetic and can be made hard, unlike 304. Because it can be made hard, it is often used for cutting tools such as knives, scalpels and ball bearings. While 304 is known as austenitic steel, which has fairly good corrosion resistance. It is not magnetic and is used in food service and chemical industries because of its ability to resist rust and chemical attacks. See here for a comparison of 420 and 304.
420 and 304 are among the most popular types of stainless steel in Vietnam. However, users are still wondering which option is better for their needs. Let's compare 420 and 304 through this article.

What is stainless steel 420?

420 is a high carbon stainless steel with a minimum CROM content of 12%, and is a recyclable alloy that will not destroy its inherent properties.
Stainless steel 420 can also be hardened by heat treatment, giving the product good plasticity and good corrosion resistance when the metal is polished and the surface is grounded.
420 is a very special internal crystal structure that has high magnetic properties. Due to this property, the product is widely used in products that require magnetism and are combined with magnetism.

What is stainless steel 304?

304 is a stainless steel alloy that is deeply loved by customers. Stainless steel 304 has many different names, such as SUS 304, stainless steel 304, stainless steel 304.
304 is the most common stainless steel composite material, its main metal component is iron, containing chromium and nickel, so the hardness of stainless steel is very high.
304 steel has lower electrical and thermal conductivity than carbon steel, but has higher corrosion resistance than ordinary steel, and is widely used because it is easy to form different shapes and punch holes.

Differences between 420 and 304

Due to having different number of components and internal structures, 420 and 304 have many differences. The most obvious ones are:
Chemical composition of stainless steel 304 and 420
304: The chemical composition of this product includes Niken 8.1%, Mangan 1%, 18% Crom, and the rest is iron, which is divided into two common types: 304L, which has a lower carbon content (less than 0.03%), and 304H, which has a carbon content higher than 0.08%.
420: The chemical composition of 420 and 304 both contain crom. 420 alone has 17.5% to 20% crom, while niken is 8% to 11%, and the carbon content is relatively high, 0.2% and 0.3% respectively.
Wear resistance of stainless steel 420 and 304
Your night single resistance: There are many great ways of atmospheric environment and corrosion, but special attention needs to be paid when using it. In this stress, chlorination warms up to about 60°C, which is easy to cause a noticeable and wear-resistant defect.
Stainless steel 420: In hard conditions, steel type 420 is resistant to water, alkali, air, food and light acid, especially when the surface is smooth, the performance will be very good. The wear resistance of the 420 layer will be reduced under hot and humid conditions.
Heat resistance of stainless steel 304 and 420
Stainless steel 304: Both stainless steel 420 and 304 have high heat resistance. Your night does not want to give up, up to 870°C, and continuous to 925°C. However, stainless steel night is easily damaged when the treatment has been in continuous use at about 425-860°C, because of corrosion in contact with moisture.
Stainless steel 420: The stainless steel resilient layer 420 has the ability to withstand temperatures up to 650°C. But it is not recommended to use it at heating temperatures because it may reduce the mechanical properties.
Stainless steel 420 vs. stainless steel 304 hardness
Stainless steel 304: Through the stamping process, the plasticity of the plastic is reduced, making the hardness of 304 stainless steel very high, more than 60. However, in tropical saltwater conditions, such as oil rigs or gas rigs, chlorates may break.
Stainless steel 420: During heat treatment, due to the composition of more crom and carbon, there will be high hardness, which makes the internal molecules more tightly bonded, but it is easy to break at zero degrees.
Application of stainless steel 304 and 420
Stainless steel 304: Stainless steel 304 is suitable for a variety of household and industrial applications, such as food processing equipment, screws, mechanical parts, tableware and exhaust pipes. The product is also used for building facades, such as waterproofing, fireproofing, etc.
Stainless steel 420: 420 grade is often used in medical treatment to manufacture treatment instruments, such as dental and surgical instruments, knives, scissors, skin cutting, acupuncture.

Which is better, stainless steel 304 or 420?

304 will have stronger corrosion resistance, product life, high plasticity, better bending and bending performance than 420. This means that the price of 304 stainless steel will be higher.

Core difference contrast

peculiarity	304 stainless steel (austenite)	420 stainless steel (martensite)
Main component	18% chromium, 8% nickel, low carbon	12-14% chromium, 0.15-0.4% carbon, no nickel
Corrosion resistance	Strong (acid and alkali resistance, salt spray)	Weak (only weak corrosion resistance, easy to rust)
hardness	(HRB 70-90, soft)	(HRC 50-55, heat-treatable)
magnetism	None (may have weak magnetism after cold working)	Have strong magnetism
Processing difficulty	Easy to weld and press	Need to preheat, welding is easy to crack
Price	Higher (including nickel cost)	Lower (no nickel)

The difference between 420 stainless steel and 304 stainless steel production process

1.Raw materials and smelting stage

Process link	304 stainless steel (austenite)	420 stainless steel (martensite)
Main component	18% Cr, 8% Ni, low carbon (≤0.08%)	12-14% Cr, 0.15-0.4% C, nickel free
Smelting method	Electric arc furnace (EAF) + AOD (argon-oxygen decarburization) refining	Electric Arc Furnace (EAF) + LF (Ladle Refining)
Critical control point	Strictly control carbon content (C≤0.08%) Ensure stable nickel content (8-10%)	Control carbon content (0.15-0.4%) Avoid chromium oxidation loss

2.Casting and hot rolling

Process link	304 stainless steel	420 stainless steel
Continuous casting/ingot casting	Continuous casting billet (slab/square)	Ingot casting (part to be forged)
Hot rolling temperature	1150-1250℃ (high temperature plasticity is good)	1000-1100℃ (avoid grain coarsening)
Cool after hot rolling	Air cooling (maintaining austenitic structure)	Rapid cooling (quenching) to obtain martensite

3.Cold rolling and annealing

Process link	304 stainless steel	420 stainless steel
Cold rolling deformation	Up to 80% (work hardening apparent)	Usually 50-60% (high carbon prone to cracking)
Annealing process	Solution treatment (1050-1100℃ fast cooling)	Annealing (slow cooling at 800-900℃) or quenching + tempering
Ultimate organization	Austenite (non-magnetic/weak magnetic)	Tempered martensite (high hardness + magnetic)

4.Surface treatment

Process link	304 stainless steel	420 stainless steel
Pickling passivation	Commonly used (to improve corrosion resistance)	Less (mainly used to remove oxide)
Polishing/drawing	Widely used (decorative)	Mostly used for tools/tools (functional)
Coating/coating	Less (intrinsic corrosion resistance)	Possible chrome/nitriding (enhanced wear resistance)