440C
AISI 400C is a chromium-rich, high-carbon steel that is specifically engineered to possess stainless steel characteristics while maximizing its hardness. Following the heat-treatment process, Type 440C achieves the utmost hardness among all
stainless steel types, measuring approximately 60 HRC. This particular stainless steel is primarily employed in bearing assemblies, such as ball bearings, and is worth considering for applications involving needle valves and ball check valves.
Chemical Composition Limits
| Weight% | C | Si | Mn | P+S | Cr | Mo | Ni | Others |
| AISI 440C | 0.95/ 1.2 | 1.0 max | 1.0 max | 0.04 P 0.03 S | 16.0 / 18.0 | 0.75 | – | – |
| AFNOR Z100 CD 17 | 0.90/ 1.2 | 1.0 max | 1.0 max | 0.04 P 0.03 S | 16.0 / 18.0 | 0.35 / 0.75 | 0.50 max | Cu 0.50 max |
| AMS 5630 | 0.95/ 1.2 | 1.0 max | 1.0 max | 0.04 P 0.03 S | 16.0/ 18.0 | 0.4/ 0.65 | 0.75 max | Cu 0.50 max |
| WS 1.4125 M-17C Chronifer X 105 CrMo17 Z100 CD 17 | 0.95/ 1.2 | 1.0 max | 1.0 max | 0.015 S max | 16.0/ 18.0 | 0.8 max | – | – |
Mechanical Properties
| Material | Condition | Yield Strength 0.2% (MPa) | Ultimate Tensile Strength (MPa) | Elongation 2″% | Reduction of Area | Brinell Hardness |
| Alloy 440C | Hardened 1900°F, oil quench, tempered 600°F | 1896 | 1965 | 2 | 10 | 580 |
Specifications
| UNS S42000 | 440C Vac Melt |
| AMS 5618 Bars / wire / forging (VM) | AMS 5630 Bar, Wire, Forgings |
| AMS 5880 Bars / wire (bearing apps) | QQ-S-763 |
| ASTM A276 / ASME SA276 | ASTM A314 / ASME SA314 |
| ASTM A473 / ASME SA473 | ASTM A484 / ASME SA484 |
| ASTM A493 / ASME SA493 | ASTM A756 / ASME SA756 |
| ASTM A580 / ASME SA580 | AISI 440C |
| WS 1.4125 | AFNOR Z100CD17AFNOR Z100CD17 |
| X105CrMo17 | UNS S44004 |
| RBO 160-064CF13 | – |