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PRODUCT DATA of AISI 440B
MaterialAISI 440B
Product Datasheet440B
General InformationThis is a high carbon martensitic stainless with moderate corrosion resistance good strength and the ability to obtain and keep excellent hardness (Rc 58) and wear resistance.

Data for hardened and stress relieved

PrecautionsCracking may occur on heating, cooling, pickling or after welding. These steels are particularly subject to decarburization because of their high carbon content. Use of protective, on-decarburizing atmospheres in heat treatments is recommended. This steel is subject to severe embrittlement by gaseous hydrogen
Chemical CompositionFe-17Cr-0.85C
PHYSICAL PROPERTIES
Crystal StructureFace centered cubic (fcc)
Specific Gravity7.65
Magnetic PropertiesFerromagnetic
ELECTRICAL PROPERTIES
Electrical Volume Resistivity6e-7 ohm.m
THERMAL PROPERTIES
Thermal Conductivity24.2 W/m.K
Thermal Expansion Coefficient10.1 μstrain/°C
Melting Range1370 to 1510 °C
Specific Heat0.46 J/g.K
RELEVANT PROPERTIES FOR USE IN SPACE COMMUNITY
General Corrosion StatusRequires specific corrosion protection
Stress Corrosion StatusLow Resistance to SCC: Table 3
Data Quality: Design Data
EMF vs SCE-0.23 V
Remark: Measured in 3.5% NaCl solution. Passive condition
Data Quality: Design Data
Bimetallic CorrosionCan 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
MachinabilityBest machined in the annealed condition. Tough, stringy chips can be best handled by the use of chip breakers. Carbide or ceramic tooling is recommended
WeldingThis alloy is not commonly welded due to its tendency to air harden.
FLUID SYSTEMS COMPATIBILITY
Low Pressure Hydrogen (LOH2)Fails mechanical impact
High Pressure Hydrogen (HIH2)Fails mechanical impact
SPECIAL RECOMMENDATIONS
Special RecommendationsCracking may occur on heating, cooling, pickling or after welding. These steels are particularly subject to decarburization because of their high carbon content. Use of protective, on-decarburizing atmospheres in heat treatments is recommended.