420 mod. Stainless Steel - 1.4021 - X20Cr13 - ~SUS 420J1

Where can stainless steel 420 mod. be used?

The 420 mod. can be used for applications needing high hardness, strength and moderate corrosion resistance like kitchenware, cutlery, pumps, shafts valves or machine components like gears, bolts and nuts. 

Is the 420 mod. a stainless steel?

Yes, the 420 mod. is a stainless steel. A stainless steel has a minimum mass fraction of 10.5% chromium. The 420 mod. has a mass fraction of 12 - 14% of chromium.

Is the 420 mod. corrosion resistant?

Yes, with a mass fraction of 12 - 14% of chromium the 420 mod. is a corrosion resistant steel. 

General corrosion of the Stainless 420 mod.

This stainless steel has good corrosion resistance in slightly corrosive environments free of chlorides like detergents, organic acid, or soaps. 420 mod. is resistant to oxidation up to a temperature of 1112°F (600°C). This grade is not suitable to be used in sea water as pitting corrosion will occur when used in this environment. In general, the corrosion resistance of this steel grade is lower than common austenitic grades. To enhance corrosion resistance for this steel, parts should be finished with a finely ground or polished surface.

Is stainless steel 420 mod. magnetizable?

The 420 mod. can be magnetized which is beneficial for applications where magnetic properties are needed and is suitable for magnetic clamping.

420 mod. stainless steel heat treatment

Specific temperatures and times for each of the following steps can vary based on size and shape of the workpieces and their final desired properties. Controlled heating and cooling is crucial to achieve the ideal structure and properties for this steel grade.

Annealing 420 modstainless steel 420 mod.

Heat the material uniformly to a temperature range of 1373 - 1517°F (745 - 825°C), hold and follow this with a slow cooling in air or in the furnace.

Stress relieving stainless steel 420 mod.

Stress relieving the 420 mod. is done to ensure dimensional stability and to prevent cracking. Heat the material to a temperature range between 300 - 390°F (150 - 200°C) and hold for 2 hours per inch (25.4 mm) of thickness. To finish this process, cool the material down to room temperature in still air. Finally inspect the material to see that the reduction of residual stresses has been achieved and mechanical properties and dimensions have not been altered.

Hardening stainless steel 420 mod.

Heat the material uniformly to a temperature of 1922 - 1742°F (950 - 1050°C) and hold, then cool in oil or air. As the hardness of the 420 mod. increases the tensile strength also increases.

Quenching stainless steel 420 mod.

Quenching is done rapidly to transform austenite back to martensite. 

• Oil
• Air
• Polymer

Tempering 420 mod. stainless steel

The tempering temperature is chosen for hardness requirements, to reduce brittleness after quenching or to adjust the balance between hardness and toughness. Tempering temperatures for the 420 mod. are between 1112 - 1292°F (600 - 700°C), the temperature range of 752 - 1112°F (400 - 600°C) should be avoided due to precipitation and unwanted phases.

Dimensional changes of the 420 mod. stainless steel

Dimensional changes can occur during heat treatment, cooling and manufacturing. Heating and cooling lets any material grade expand or contract but also can phase changes and stress relieve be a factor for dimensional changes and should be considered when tight tolerances are needed. Controlled heat treatment and good machining practices can support dimensional stability.

Surface treatment for stainless steel 420 mod.

Surface treatment can enhance properties, corrosion resistance, wear resistance as well as aesthetics of a steel. Here are a few examples of surface treatments for the 420 mod.

Polishing the 420 mod. stainless steel

Polishing the 420 mod. to a high gloss finish can enhance corrosion resistance or remove contaminants from the surface but also enhances the aesthetic appeal of the material and makes it ideal for knife making.

Passivation of the 420 mod. stainless steel

The process removes free iron from the surface with nitric or citric acids and adds a protective oxide layer over the material.

Physical Vapor Deposition and Chemical Vapor Deposition of 420 mod. stainless

Both processes deposit a thin protective layer on the material surface to enhance corrosion resistance, improve wear resistance or reduce friction.

Shot peening / shot blasting 420 mod. stainless steel

This process is an impact treatment where multiple high velocity shots are blasted onto the material surface leaving small indentations removing stress risers. It makes the surface more resistant and can prevent fatigue and stress corrosion failure.

Note: Protective gear like goggles, masks, helmets, gloves and protective clothing should be worn and adequate ventilation or dust extraction should be provided.

Appropriate guards to prevent shot spillage should be in place, equipment regularly maintained and shot should be free from contaminants.

Bead blasting / abrasive blasting the 420 mod. stainless steel

Abrasive particles like glass or ceramic beads are blasted against the surface to remove contaminants like rust, paint or scale and to promote a uniform matt finish.

Note: Care has to be taken during this process as the process produces dust and small parts might be propelled back. Protective gear like masks, helmets and protective clothing should be worn and adequate ventilation or dust extraction should be provided.

Black oxide (bluing) stainless steel 420

This is a superficial treatment that may enhance corrosion resistance but is most often used to color the surface blue-black to reduce the reflection of light.

Laser surface melting the 420 mod. stainless steel

In this process a laser melts a thin layer with a high power beam which is followed by rapid cooling and solidifying of the material. This improves the surface hardness and corrosion resistance. 

Machinability for stainless steel 420 mod.

Machining 420 mod. is essentially no different than machining non-alloy carbon steels of similar or matching strength.

Forging stainless steel 420 mod.

Slowly and uniformly preheat the material to a temperature of 1562°F (850°C) and then more rapidly to the temperature range of 2102 - 21056°F (1150 - 1180°C). Forge the parts at the range of 2012 - 1652°F (1100 - 900°C) and finish the process by cooling the parts down slowly in the furnace or dry ash or similar materials that promote slow cooling.

Welding stainless steel 420 mod.

Though 420 mod. has poor weldability it can be welded by all types of welding processes. When gas welding care should be taken to avoid contamination, for example nitrogen or hydrogen, as this will affect the mechanical properties of the parts.

Preheat parts to 392 - 572°F (200 - 300°C) and if a filler is needed it should match the base metal. Let the parts cool down to 248°F (120°C) before tempering. To restore some of the ductility in the weld zone it should be tempered at a temperature of 1202°F (650°C).

Wear resistance of the 420 mod. stainless steel

The wear resistance of the 420 mod. is 3 on a scale where 1 is low and 6 is high.

Tensile strength for 420 mod. stainless steel

The tensile strength for the 420 mod. is approx. 123.2 KSI (0.145KSI = 1MPa). This value is the result from a tensile test to show how much force is needed before the material starts to stretch or elongate before it breaks.

Yield strength of stainless steel 420 mod.

The yield strength shows how much stress can be applied to a material before it plastically deforms. Beyond this point it does not return to its original form when the stresses have been removed.The material deforms permanently or breaks past that point. 

The range for the stainless steel 420 mod. is between 72.5 to 87.0 KSI (500 - 600 MPa).

Working hardness for 420 mod. stainless steel

The working hardness for the stainless steel 420 mod. is at approx. 250 BHN (delivery condition) - 445 BHN (25 HRC (delivery condition) - 47 HRC).

Specific heat capacity for stainless steel 420 mod.

The specific heat capacity of the 420 mod. stainless steel at room temperature is at 0.46 J/g-°C (0.109 BTU/lb-°F). This value shows how much heat is needed  to heat 1lb of material by 1 Fahrenheit.

Steel Properties of stainless steel 420 mod.

Hot working stainless steel 420 mod.

Heat the material uniformly to a temperature range of 2100 - 2250°F (1149 - 1232°C). Hot working this steel below 1700°F (927°C) should be avoided as cracking may occur.

Corrosion resistance is compromised by discoloration caused by hot forming, welding or by scaling. These should be removed by pickling (pickling solution), grinding or sandblasting. For this process only iron-free tools may be used.

Cold working stainless steel 420 mod.

It is not recommended to cold work this material in this condition, only for minor modifications can be done to the material. Severe manipulation will result in cracking of the material. This steel grade is most often machined to shape.

Steel Density for stainless steel 420 mod.

Typically the density of 420 mod. stainless steel is 0.278 lb/in3 (7.7g/cm3) at room temperature.

Thermal conductivity of stainless steel 420 mod.

The heat conductivity for the 420 mod. stainless steel is at 30 W/(m*K) (208 BTU/(h-ft*°F)) at room temperature.

Thermal expansion coefficient for stainless steel 420 mod.

This diagram shows how much the 420 mod. might expand or contract when the temperatures change which can be very important when working with high temperatures or strong temperature changes.

Specific electrical resistivity of stainless steel 420 mod.

The following table shows the electrical resistivity of stainless steel 420 mod. 

Modulus of elasticity (Young’s Modulus) for stainless steel 420 mod.

The stress and strain modulus or modulus of elasticity (Young’s modulus) for 420 mod. stainless steel is at 31.183 KSI (215 GPa). 

Is the 420 mod. stainless steel, knife steel?

The 420 mod. can be used for knife blades, surgical instruments as well as cutting tools as it has an excellent hardness after heat treatment. So yes, the 420 mod can be used as a knife steel.

Conclusion

The 420 mod. is well suited for applications which need a good balance of wear resistance and moderate corrosion resistance. It can be used in mild environments and due to durability and wear resistance can be used to manufacture surgical instruments or cutlery.

All in all a very versatile stainless steel with a good variety of applications.

Datasheet for stainless steel 420 mod.

As a steel supplier we provide you with the datasheet for stainless steel 420 mod. in PDF format.

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