Specified Properties
These properties are specified for bar product in ASTM A276. Similar but not necessarily identical properties are specified for other products such as wire and forgings in their respective specifications. These grades are not normally available in flat rolled or fluids products.
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N |
|---|---|---|---|---|---|---|---|---|---|
| 440A | min. 0.65 max. 0.75 | – 1.00 | – 1.00 | – 0.040 | – 0.030 | 16.00 18.00 | – 0.75 | – | – |
| 440B | min. 0.75 max. 0.95 | – 1.00 | – 1.00 | – 0.040 | – 0.030 | 16.00 18.00 | – 0.75 | – | – |
| 440C | min. 0.95 max. 1.20 | – 1.00 | – 1.00 | – 0.040 | – 0.030 | 16.00 18.00 | – 0.75 | – | – |
| Tempering Temperature (°C) | Tensile Strength (MPa) | Yield Strength 0.2% Proof (MPa) | Elongation (% in 50mm) | Hardness Rockwell (HR C) | Impact Charpy V (J) |
|---|---|---|---|---|---|
| Annealed * | 758 | 448 | 14 | 269 HB max # | – |
| 204 | 2030 | 1900 | 4 | 59 | 9 |
| 260 | 1960 | 1830 | 4 | 57 | 9 |
| 316 | 1860 | 1740 | 4 | 56 | 9 |
| 371 | 1790 | 1660 | 4 | 56 | 9 |
| Grade | Density (kg/m³) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion 0-100°C (m/m/°C) | 0-200°C (m/m/°C) | Thermal Conductivity at 100°C (W/m.K) | at 500°C (W/m.K) | Specific Heat 0-100°C (J/kg.K) | Electrical Resistivity (nΩ.m) |
|---|---|---|---|---|---|---|---|---|
| 440A/B/C | 7650 | 200 | 10.1 | 10.3 | 24.2 | – | 460 | 600 |
| Grade | UNS No | Euronorm | Swedish SS | Japanese JIS | |
|---|---|---|---|---|---|
| No | Name | ||||
| 440A | S44002 | – | – | – | SUS 440A |
| 440B | S44003 | 1.4112 | X90CrMoV18 | – | SUS 440B |
| 440C | S44004 | 1.4125 | X105CrMo17 | – | SUS 440C |
Grade 420 stainless steel is a higher carbon version of 410; like most carbon and low alloy steels it can be hardened by heat treatment. It contains a minimum of 12 per cent chromium, just sufficient to give corrosion resistant properties. 420 has good ductility in the annealed condition but is capable of being hardened up to Rockwell Hardness 50HRC, the highest hardness of the 12 per cent chromium grades. Its best corrosion resistance is achieved when hardened and surface ground or polished.
Related grades to 420 are high carbon high hardness martensitic stainless steels such as the 440 series (see the IIQ Datasheet on this series of grades) and also variations to 420 containing molybdenum (for increased corrosion resistance and mechanical properties), sulphur (for increased machinability) or vanadium (for higher hardness). A slightly higher carbon version of 420 is the non- standard grade 420C.
Martensitic stainless steels are optimised for high hardness, and other properties are to some degree compromised. Fabrication must allow for poor weldability and usually also include a final harden and temper heat treatment. Corrosion resistance is lower than the common austenitic grades, and their useful operating temperature range is limited by their loss of ductility at sub- zero temperatures and loss of strength by over- tempering at elevated temperatures.
Grade 420 in the hardened condition has good resistance to the atmosphere, foods, fresh water and mild alkalies or acids. Corrosion resistance is lower in the annealed condition. Less corrosion resistant than the austenitic grades and also less than 17% chromium ferritic alloys such as Grade 430; 420 also has slightly lower resistance than grade 410. Performance is best with a smooth surface finish.
This grade is commonly used for cutlery – particularly blades of table knives and for some carving knives and similar. The corrosion resistance is sufficient to resist food and normal washing methods, but prolonged contact with unwashed food residues can result in pitting.
Not recommended for use in temperatures above the relevant tempering temperature, because of reduction in mechanical properties. The scaling temperature is approximately 760°C .
Process Anneal – 735-785°C and air cool.
The tempering range 425-600°C should be avoided.
Pre- heat to 150 – 320°C and post- heat at 610 – 760°C . Grade 420 coated welding rods are recommended for high strength joints, where a post- weld hardening, and tempering heat treatment is to be carried out. If parts are to be used in the “as welded” condition, a ductile joint can be achieved by using Grade 309 filler rod. AS 1554.6 prequalifies welding of 420 with Grade 309 rods or electrodes.
In the annealed condition this grade is relatively easily machined, but if hardened to above 30HRC machining becomes more difficult. Free machining grade 416 (refer IIQ Data Sheet) is a very readily machined alternative.
Cutlery, knife blades, surgical instruments. Needle valves. Shear blades.
These properties are specified for bar product in ASTM A276. Bar is the most commonly available form of grade 420. Similar but not necessarily identical properties are specified for other products such as plate and forgings in their respective specifications.
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N |
|---|---|---|---|---|---|---|---|---|---|
| 420 | min. 0.15 — max. – | 1.00 | 1.00 | 0.040 | 0.030 | 12.00 14.00 | – | – | – |
| 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 | 255 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 | 26 |
| Grade | Density (kg/m³) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion 0-100°C (μm/m/°C) | 0-315°C (μm/m/°C) | Thermal Conductivity at 100°C (W/m.K) | at 500°C (W/m.K) | Specific Heat (J/kg.K) | Electrical Resistivity (nΩ.m) |
|---|---|---|---|---|---|---|---|---|
| 420 | 7700 | 200 | 10.3 | 10.8 | 24.9 | – | 460 | 550 |
| Grade | UNS No | Euronorm | Swedish SS | Japanese JIS | |
|---|---|---|---|---|---|
| No | Name | ||||
| 420 | S42000 | 1.4021 | X20Cr13 | 2303 | SUS 420J1 |