Jun 19 2013
Topics Covered
Introduction
Chemical Composition
Other Designations
Fabrication and Heat Treatment
Machinability
Welding
Annealing
Heat Treatment
Hardening
Applications
Introduction
Stainless steel grade 420J2 is inexpensive and highly corrosion resistant steel. It has good corrosion resistance in mild atmosphere as well as domestic and industrial environments. It is also resistant to dilute nitric acid, carbonic acid, ammonia, crude oil, detergent solutions, vinegar, food acids, several petroleum products, and steam.
Stainless steel grade 420J2 is known to possess good strength and reasonable impact resistant properties in hardened and tempered conditions when compared with 440 grades.
The following sections will discuss in detail about stainless steel grade 420J2.
Chemical Composition
The chemical composition of stainless steel grade 420J2 is outlined in the following table.
|
Element |
Content (%) |
|
Chromium, Cr |
14 |
|
Nickel, Ni (optional) |
1 |
|
Manganese, Mn |
1 |
|
Silicon, Si |
1 |
|
Phosphorus, P |
0.04 |
|
Carbon, C |
0.15-0.36 |
|
Sulfur, S |
0.03 |
|
Iron, Fe |
Balance |
Other Designations
Other designations that are equivalent to stainless steel grade 420J2 include the following.
-
BS970 Part3 1991 420S37
-
BS970 Part4 1970/73 420S45
-
BS970 1955 EN56C
-
ASTM A276-98b 420
-
EN56D
-
AISI 420
-
JIS G4303
-
SUS 420 J1
-
SAE 51420
-
SUS 420 J2
Fabrication and Heat Treatment
Machinability
Stainless steel grade 420J2 is machinable both in hardened and tempered conditions such as turning, drilling, and bending; however it is recommended that machining in hardened condition should be avoided as far as possible.
Welding
Welding of stainless steel grade 420J2 is easy. It is recommended that welding in annealed or hardened and tempered conditions should be avoided as it causes formation of brittleness, resulting in cold cracking due to contraction stresses.
Pre-heating and inter-pass temperature control during welding, followed by very slow cooling and post-weld annealing are good measures to take to prevent cracking.
Annealing
Annealing of this material can be performed by heating uniformly to 840-900°C (1544-1652°F) and held until the temperature is uniform throughout the section. Soaking and cooling is required.
Heat Treatment
Stainless steel grade 420J2 has to be heated uniformly to 730-790°C (1346-1454°F) and held until temperature is uniform throughout the section.
Hardening
Stainless steel grade 420J2 can be hardened by heating 950-1020°C (1742-1868°F) and held until temperature is uniform throughout the section. This should be followed by quenching in oil or air cooling. Tempering should be done when it is slightly warm.
Applications
Stainless steel grade 420J2 is used in the following application areas:
-
Surgical instruments
-
Daggers and swords
-
Budget knives and diving knives
-
Haircutting scissors and domestic scissors