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| PRODUCT DATA of AISI 440A |
| Material | AISI 440A |
| General Information | This is a high carbon martensitic stainless with moderate corrosion resistance good strength and the ability to obtain and keep excellent hardness (Rc 56) and wear resistance. |
| Use in Spacecraft | Ball bearings and races, gage blocks, molds and dies, valve components |
| Chemical Composition | 0.6-0.75C, 16-18Cr, rem Fe |
| EXPERIENCE IN PRACTICE |
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| Development Status | Commercial Product |
| Cost Range | Low |
| PHYSICAL PROPERTIES |
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| Crystal Structure | Face centered cubic (fcc) |
| Magnetic Properties | Ferromagnetic |
| ELECTRICAL PROPERTIES |
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| Electrical Volume Resistivity | 6e-7 ohm.m |
| THERMAL PROPERTIES |
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| Thermal Conductivity | 24.2 W/m.K |
| Thermal Expansion Coefficient | 10.2 ustrain/C |
| Specific Heat | 0.46 J/g.K |
| RELEVANT PROPERTIES FOR USE IN SPACE COMMUNITY |
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| General Corrosion Status | Requires specific corrosion protection |
| Atmospheric Corrosion | This alloy is not really stainless. Should be covered with oil or grease at all times. |
| Stress Corrosion Status | Low Resistance to SCC: Table 3 Data Quality: Design Data |
| Bimetallic Corrosion | Can be connected without any restriction to: Cr, Au, Ag, Gun-metal, P-bronzes, Sn-bronzes, Ti+alloys, Ni, Monel, Inconel, Ni/Mo alloys
Can be connected in a non-controlled environment to the above and Cd, austenitic cast iron, Cu, Brasses, Al-bronzes, Si-bronzes, Au, Pt, C, Rh, Sn-Pb alloys, Sn, Pb, 300 series stainless steels Can be connected in a clean room environment to above and Al-Cu alloys Needs specific measures: All others Test:ECSS-Q-ST-70C Rev.1 Table 5.1 Data Quality: Design Data |
| Machinability | est machined in the annealed condition. Tough, stringy chips can be best handled by the use of chip breakers. Carbide or ceramic tooling is recommended. |
| Welding | This alloy is not commonly welded due to its tendency to air harden. |