SS 420 is a heat treatable martensitic chromium stainless steel. Melt practice is controlled to develop a surface nearly free from defects. It provides the best combination of wear resistance and corrosion resistance, and is used in demanding medical accessories, such as high quality surgical instruments.
The alloy can be cold formed from the annealed temper.Welding should be accomplished by pre and post heating.Pre-heating at 450° F and post-heated at 1300° F will
prevent cracking. The corrosion resistance is optimized in the heat treated temper and assured by passiviation. It is resistant to water and organic materials. Oxidation resistance remains favorable in most applications up through 1200°F.
Available Sizes:
SS 420 is available from Hamilton Precision Metals as strip product from 0.001” to 0.060” (0.0254 mm to 1.524 mm) in widths up to 12.0” (304.8 mm). The material conforms to UNS S42000.
Nominal Composition
| SS 420 NOMINAL COMPOSITION |
| Chromium |
12.5%
|
| Manganese |
0.50%
|
| Silicon |
0.50%
|
| Nickel |
0.20%
|
| Carbon |
0.22%
|
| Iron |
Balance
|
Mechanical Properties
| SS 420 MECHANICAL PROPERTIES |
|
ANNEALED |
COLD ROLLED |
HEAT TREATED |
| Ultimate Tensile Strength |
85,000 PSI |
120,000 PSI |
250,000 PSI
|
| Yield Strength (0.2% Offset) |
50,000 PSI |
90,000 PSI |
200,000 PSI |
| Elongation in 2” * |
25%
|
10%
|
5% |
| Hardness (DPH – 1000 Grams) |
200
|
220 |
540 |
| Modulus of Elasticity (Tension) |
29 x 106
PSI
|
- |
- |
| Poisson’s Ratio |
0.24
|
- |
- |
*The measured elongation will be less as thickness decreases to 0.002” and less
These values may be adjusted by control of process variables – consult HPM for desired values.
Physical Properties
| SS 420 PHYSICAL PROPERTIES |
| Density (Heat Treated) |
0.28 lbs/cu.in. |
| Melting Point (Approx.) |
1460°C |
| Electrical Resistivity @ R.T. |
55 Microhm·cm |
| Thermal Expansion Coefficient (0° to 100°C) |
10.3 x 10-6/°C |
|
Thermal Conductivity @ 100°C
|
24.9 W/m·K
|
| Magnetic Attraction
|
Yes
|
Typical values to guide alloy selection but are not a guarantee of minimum or maximum.