Stainless steel is a type of steel that has a high resistance to corrosion and rusting. It is widely used in various industries and applications, such as kitchenware, appliances, construction, automotive, etc. However, not all stainless steel grades are the same. There are different types of stainless steel with different chemical compositions, mechanical properties and performance characteristics. In this blog post, we will introduce one of the common stainless steel grades: SUS430.

Stainless steel SUS430 is a type of ferritic stainless steel with a high resistance to corrosion and rusting. It is part of the 400 series of stainless steels, which are characterized by their ferritic or martensitic structure and contain only chromium. SUS430 contains 16-18% chromium and has good stress corrosion resistance, low thermal expansion coefficient, and good oxidation resistance. It is commonly used in various applications, such as kitchenware, appliances, construction, automotive, etc. It is also a low-cost alternative to austenitic stainless steels like SUS304 for some low-end products that do not require high corrosion resistance or strength. SUS430 is a Japanese standard for stainless steel, and its equivalent in China is 1Cr17.

What is the chemical composition of Stainless steel SUS430?

The chemical composition of Stainless steel SUS430 is:

Carbon ©: 0.12% max

Silicon (Si): 0.75% max

Manganese (Mn): 1.00% max

Phosphorus (P): 0.04% max

Sulfur (S): 0.03% max

Chromium (Cr): 16.0-18.0%

Nickel (Ni): 0.75% max

Nitrogen (N): not specified

SUS430 is a ferritic stainless steel that contains only chromium as the main alloying element. It has good corrosion resistance and formability, but lower strength and ductility than austenitic stainless steels that contain chromium and nickel.

What are the mechanical properties of Stainless steel SUS430?

The mechanical properties of Stainless steel SUS430 are:

Tensile strength: 450-600 MPa

Yield strength: 205-275 MPa

Elongation: 16-22%

Brinell hardness: 183 HBW max

Rockwell hardness: 89 HRBW max

Modulus of elasticity: 200 GPa

Thermal expansion coefficient: 10.4-12.0 μm/m·°C

Thermal conductivity: 25 W/m·K

Specific heat capacity: 460 J/kg·K

Electrical resistivity: 0.60 μΩ·m

SUS430 is a ferritic stainless steel that has good formability and weldability, but lower ductility and toughness than austenitic stainless steels. It also has good corrosion resistance in mild environments, but may suffer from intergranular corrosion or stress corrosion cracking in some conditions.

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Physical properties of SUS430:

Density: 7.8 g/cm3

Melting point: 1425-1510 °C

Specific heat capacity: 460 J/kg·K

Electrical resistivity: 0.60 μΩ·m

Magnetic permeability: 600-1100 (approximate)

Modulus of elasticity: 200 GPa

Thermal diffusivity: 7.3 mm2/s

Thermal conductivity: 25 W/m·K

Coefficient of thermal expansion: 10.4-12.0 μm/m·°C

SUS430 is a ferritic stainless steel that has a low thermal expansion coefficient and a good oxidation resistance at high temperatures. It also has a high electrical resistivity and a high magnetic permeability compared to austenitic stainless steels.

What is the processing method of Stainless steel SSUS430?

The processing method of Stainless steel SSUS430 includes the following steps:

Cold forming: SUS430 can be cold formed with low amount of deformation above room temperature. Sharp chamfers parallel to the direction of rolling have to be avoided. Sheets with greater thicknesses and/or higher amount of deformation should be preheated up to 200-400 °C. If applicable, a hot forming at 700-900 °C can be necessary.

Heat treatment: SUS430 is not hardenable by thermal treatment. The recommended annealing treatment is to heat to 815-845 °C, hold for ½ hour per 25 mm of thickness, slow furnace cool to 600 °C and then quickly air cool. Slow cooling from 540-400 °C will cause embrittlement. Sub-critical annealing can be done by heating to 760-815 °C and then air cooling or water quenching.

Welding: SUS430 has good weldability and can be welded by various methods such as TIG, MIG, spot and seam welding. Pre-heating at 150-200 °C is necessary if welding is required. Embrittlement in the weld metal and heat affected zone can be relieved by a post-weld anneal at 790-815 °C. Grain refinement will not occur.

Machining: SUS430 has good machinability and can be easily cut, drilled, turned and milled. However, it has lower ductility and toughness than austenitic stainless steels, so it may require more frequent tool changes and lubrication. SUS430F is a free-machining version of SUS430 that has better machinability due to the addition of sulfur.

What are the characteristics of stainless steel SUS430?

The characteristics of stainless steel SUS430 are as follows:

Ferritic stainless steel: SUS430 is a straight chromium, non-hardenable grade that has a ferritic structure at all temperatures. It has good corrosion resistance and formability, but lower strength and ductility than austenitic stainless steels.

Nitric acid resistance: SUS430 has the ability to resist nitric acid attack, which permits its use in specific chemical applications. It also has good resistance to some organic acids and mild environments.

Heat resistance: SUS430 resists oxidation in intermittent service up to 870°C and in continuous service up to 815°C. However, it may become brittle at room temperature after prolonged heating in the 400-600°C range. This effect can be eliminated by annealing.

Magnetic properties: SUS430 is magnetic due to its ferritic structure. It has a high magnetic permeability compared to austenitic stainless steels. It can be attracted by a magnet.

Free-machining version: SUS430F is a modified version of SUS430 that adds sulfur to improve its machinability. It is available in bar form for use in automatic screw machines. However, it has much reduced resistance to pitting and crevice corrosion compared to SUS430.

What is the application of Stainless steel SUS430?

Kitchenware: SUS430 is widely used for making various kitchen utensils, such as cutlery, cookware, sinks, stoves, etc. It has good corrosion resistance and formability, and can withstand high temperatures and frequent washing.

Automotive trim: SUS430 is also used for making some automotive trim components, such as grilles, bumpers, moldings, etc. It has good resistance to nitric acid and some organic acids, and can be polished to a high luster.

Appliance components: SUS430 is suitable for making some appliance components that do not require high corrosion resistance or strength, such as refrigerator cabinet panels, dish washer linings, etc. It has low cost and good weldability.

Industrial applications: SUS430 can be used for some industrial applications that require good oxidation resistance and low thermal expansion coefficient at high temperatures, such as lashing wire, element supports, chimney liners, etc. It also has good stress corrosion resistance and can resist cracking caused by stress and chloride ions.