420 Stainless Steel Companies and Suppliers

To provide the best services and exhibit the highest possible levels of hardness, any stainless steel 420 product should undergo heat treatment.

Heating Process

Stainless steel 420 heat treatment usually begins with annealing and continues with hardening. Annealing is a process that involves heating the steel to between 840°C and 900°C, and then allowing it to cool slowly in a furnace to around 600°C and, finally, allowing the metal to air-cool. During this state, the stainless steel has excellent ductility and can be manipulated into many shapes. Once stainless steel 420 has undergone heat treatment, it exhibits good resistance to corrosion from mild acids, alkalis, fresh water, air and food, lending it well to the applications mentioned above.

Hardening Process

During hardening, stainless steel 420 is heated to temperatures between 980°C and 1035°C, immediately followed by air or oil quenching, both of which are rapid cooling processes. Either quenching method may be chosen, but, for heavy metal sections, oil quenching is more effective. After quenching, to attain good mechanical properties and increased hardness, workers temper the steel, or bring it below its lower critical temperature. In this case, they lower the steel’s temperature to between 150°C and 350°C.

Welding Process

Other procedures commonly performed on stainless steel 420 include welding and machining. The welding process is an ideal choice for those wishing to form strong joints. Note that the metal is easily machined while annealed, but presents far more difficulties when it reaches a hardness above 30 HRC.

To maintain the health and positive properties of a stainless steel 420 product, users must follow certain maintenance and care guidelines. If they do not, their product may succumb to discoloration, rust or the influence of strongly corrosive substances. This is especially true in environments more prone to the creation of stressing environments, such as indoor swimming pools or custodial services that use harsh chemicals. In a workshop environment, to avoid contamination by carbon steel, or free iron, which frequently leads to accelerated and localized corrosion, take care to clean tools between processes.

Common spots where contamination occurs include: on steel storage racks, with tools used with other metals, on finishing belts, on grinding wheels, from wire brushes, from grinding or welding sparks, and from being adjacent to carbon steel fabrication. Keep stainless steel 420 clean by washing it with warm water and soap or a mild detergent, then rinsing it with cold water.

To enhance the surface, wipe it dry. With a little care and cleaning, stainless steel 420 parts and products can last many years; they’re well worth the investment.

Compositional Ranges of Grade 420 Stainless Steel

Carbon (C)	Manganese (Mn)	Silicon (Si)	Sulfur (S)	Phosphorus (P)	Chromium (Cr)
0.15	-	-	-	-	12.0
-	1	1	0.040	0.03	14.0

 

Mechanical Properties of Grade 420 Stainless Steel

Tempering Temperature (°C)	Tensile Strength (MPa)	Yield Strength 0.2% Proof (MPa)	Elongation (% in 50mm)	Hardness Brinell (HB)	Impact Charpy V (J)
Annealed*	655	345	25	241 max	-
204	1600	1360	12	444	20
316	1580	1365	14	444	19
427	1620	1420	10	461	#
538	1305	1095	15	375	#
593	1035	810	18	302	22
650	895	680	20	262	42

* Annealed tensile properties are typical for Condition A of ASTM A276; annealed hardness is the specified maximum

# Tempering of this steel should be avoided in the range 425-600°C

 

Physical Properties of Annealed Grade 420 Stainless Steels

Density (kg/m^3	Elastic Modulus (GPa)	Mean Coefficient of Thermal Expansion (µm/m/°C) 0 - 100°C	Mean Coefficient of Thermal Expansion (µm/m/°C) 0 - 315°C	Mean Coefficient of Thermal Expansion (µm/m/°C) 0 - 538°C	Thermal Conductivity (W/m.K) at 100°C	Thermal Conductivity (W/m.K)at 500°C	Specific Heat 0-100°C (J/kg.K)	Electrical Resistivity (nO.m)
7800	200	10.3	10.8	11.7	24.9	-	460	550

 

More 420 Stainless Steel Information