420 Stainless Steel: Properties and Applications

420 stainless steel is a common stainless steel material, with its main components being chromium (12% to 14%), carbon (0.15% to 0.40%), silicon (below 1%), manganese (below 1%), phosphorus (below 0.04%), sulfur (below 0.03%), etc. 420 stainless steel has high hardness and wear resistance, as well as good corrosion resistance, and can be used to manufacture cutting tools, blades, surgical instruments, bearing components, assembly parts, etc. The material also has easy processing and plasticity and can be easily processed into various shapes and sizes through cutting, forging, heat treatment, and other processes.

Main Properties of 420 Stainless Steel

It is a high-carbon stainless steel with the following main properties:

1. 1. High hardness: it has high hardness, which can be further increased through heat treatment. This makes it widely used in the manufacturing of cutting tools, surgical instruments, and industrial components.
   2. Good corrosion resistance: it has good corrosion resistance and can resist the attack of many chemical substances, including some acids and salt solutions. However, compared with other types of stainless steel, the corrosion resistance of 420 stainless steel is relatively low.
   3. Easy processing: it has good plasticity and machinability before heat treatment, and is easy to forge, cold draw, mill, and cut.
   4. Excellent grinding performance: it has good grinding performance, so it can be used in applications such as manufacturing cutting tools and blades that require sharp cutting edges.
   5. Medium strength and wear resistance: 420 stainless steel has moderate tensile strength and wear resistance, making it widely used in the manufacture of parts requiring wear resistance.

It is important to note that due to its high carbon content and low chromium content, 420 stainless steel may experience corrosion issues in some extreme environments, such as high temperatures and strong corrosive environments. Therefore, it needs to be evaluated and selected based on the specific application scenario.

Heat resistance of 420 stainless steel

It is a medium carbon (0.15% to 0.40%) chromium stainless steel with good heat resistance. Its heat resistance depends on the content of its alloying elements and heat treatment process.

Generally, 420 stainless steel has limited heat resistance and is more suitable for low-temperature working environments. Its maximum use temperature is usually 650°C. Beyond this temperature range, stainless steel will begin to precipitate nitrides, resulting in excessive grain growth and grain boundary corrosion, which can lead to increased thermal brittleness in the material in severe cases.

If it is necessary to improve the heat resistance of 420 stainless steel, heat treatment processes such as solution treatment, and quenching and annealing can be performed. These treatment methods can improve the grain boundary structure and grain size of the material, thereby improving its heat resistance.

In general, the heat resistance of 420 stainless steel is lower than other heat-resistant stainless steel and is suitable for use in low-temperature environments. In high-temperature applications, it is recommended to choose stainless steel materials with better heat resistance.

Heat Treatment of 420 Stainless Steel

It is a high carbon content stainless steel with excellent corrosion resistance and mechanical properties. It can further improve its performance through heat treatment. The annealing process uses 420-grade stainless steel heated to 840 to 900°C, then slowly furnace cooled at 600°C, and finally air cooled. For process annealing, 420 grade steel is heated to 735 to 785°C, and then air cooled. During the hardening process, 420-grade steel is heated to 980 to 1035°C, and then air or oil is quenched. Tempering at 150 to 370°C to obtain high hardness and good mechanical properties, but avoid tempering between 425 to 600°C.

Welding of 420 Stainless Steel

To achieve a high-strength joint, Grade 420 stainless steel welded with electrodes is used, and coated with Grade 420 metal. The steel is preheated at 150°C to 320°C, and then heated at 610°C to 760°C. During welding, Grade 309 filler rods are used for filling to obtain a good ductile joint. However, according to the recommendations of AS 1554.6, Grade 309 electrodes or wires are used to weld Grade 420 steel.

Processing of 420 Stainless Steel

It is a high-carbon stainless steel. Grade 420 steel is easily processed in the annealed state, but it is difficult to process when the hardness is greater than 30HRC. The following are common processing methods for 420 stainless steel:

1. 1. Cutting: Use a shear, cutting machine, or electric spark cutting machine to cut 420 stainless steel. Ensure that the cutting machine has the appropriate cutting capability and that the cutting tool is sharp.
   2. Welding: Use a welding method suitable for stainless steel, such as TIG welding or MIG welding. During the welding process, pay attention to controlling the temperature to avoid annealing or oxidation of the steel.
   3. Bending: Use a mechanical bending machine or manual bending tool to bend 420 stainless steel plates or bars into the desired shape. Pay attention to selecting the appropriate bending radius to avoid causing cracks during the bending process.
   4. Milling: Milling 420 stainless steel using a milling machine or gantry machining center. Selecting the appropriate tool and cutting parameters ensures a smooth cutting process and a smooth surface.
   5. Grinding: Use a grinder, polisher, or hand-held sandpaper to grind the 420 stainless steel surface to the desired finish. Select a grinding wheel or sandpaper with different particle sizes based on your needs.
   6. Drilling: Use a drill press or handheld electric drill for drilling operations. Use cobalt or titanium drills to ensure stable cutting and cooling lubrication.
   7. Turning: Turning 420 stainless steel using a lathe. Selecting the appropriate turning tool, cutting speed, and feed rate to achieve the required accuracy and surface quality.

Before any processing, it is important to choose the appropriate process and equipment based on the specific situation and follow the corresponding safety operating procedures.

Applications of 420 Stainless Steel

It is a high-carbon stainless steel, mainly composed of chromium, carbon, and molybdenum, with good corrosion resistance and strength. It has wide applications in many industries, including:

1. 1. Tool manufacturing: 420 stainless steel has good cutting performance and hardness, and is often used in the manufacture of blades, handles, tools, surgical knives, and other medical equipment.
   2. Pressure vessels: Due to its excellent corrosion resistance and high strength, 420 stainless steel is widely used in the manufacture of pressure vessels, storage tanks, and pipelines in the chemical, petroleum, and natural gas industries.
   3. Food processing equipment: 420 stainless steel meets hygiene standards and has excellent corrosion resistance and machinability, often used in the manufacture of food processing equipment, cutlery, and cutting tools.
   4. Aerospace: The strength and corrosion resistance of 420 stainless steel make it an important material in the aerospace industry, used to manufacture aircraft parts, propellers, shafts, and more.
   5. Chemical equipment: Due to its ability to resist the erosion of corrosive media such as strong acids, alkalis, and salts, 420 stainless steel is widely used in the chemical industry to manufacture chemical equipment, storage tanks, pipelines, and other components.
   6. Medical equipment: 420 stainless steel has good corrosion resistance, high-temperature strength, and low-temperature toughness, and is widely used in the manufacture of medical devices, surgical instruments, dental instruments, etc.

In summary, 420 stainless steel has a wide range of applications, including tool manufacturing, pressure vessels, food processing equipment, aerospace, chemical equipment, and medical equipment.

Conclusion

Thank you for reading our article, we hope it can help you to have a better understanding of the properties and applications of 420 stainless steel. If you want to learn more about 420 stainless steel, we’d advise you to visit Sino Stainless Steel for more information.

As a leading supplier of stainless steel products across the whole world, Sino Stainless Steel offers customers high-quality products such as stainless steel coils, stainless steel wires, stainless steel plates, and carbon steel pipes at a very competitive price.