| Abstract: | Heat treatment with mixed martensite-bainite transformation of austenite is optimized in terms of strength and fatigue-crack
resistance. For the manufacture of components in impact mechanisms, the best combination of strength, hardness, and crack
resistance is obtained for steel in which 40% martensite is formed on intermediate cooling, while isothermal heating converts
the residual supercooled austenite to lower bainite. This increases the strength by 200–250 N/mm2 in relation to quenching + tempering + isothermal quenching (with comparable crack resistance) and increases the resistance
to fatigue-crack propagation by a factor of 1.3–2 (with analogous strength). |
