AISI 4161 is a low-alloy steel of the chromium-molybdenum type; it contains nominally 0.61% carbon. It has relatively high hardenability and good resistance to abrasion, impact and fatigue. It is an oil-hardening grade and is recommended for moderately heavy-duty service. This steel has a relatively low tendency to develop temper embrittlement when tempered in the approximate range 850-1100 F. Among its many applications are springs, machine-tool parts, shafting, gears, bolts and heavy-duty hand tools. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-397. Producer or source: Alloy steel mills and foundries.