Forged part of steel and a method of manufacturing thereof
AssigneeArcelorMittal
InventorsFrancois-Xavier Hoche, Didier Forgeoux, Victor Bordereau, Bernard Resiak
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Abstract
A steel for forging mechanical parts including of the following elements 0.04%≤C≤0.28%; 1.2%≤Mn≤2.2%; 0.3%≤Si≤1.2%; 0.5%≤Cr≤1.5%; 0.01%≤Ni≤1%; 0%≤S≤0.06%; 0%≤P≤0.02%; 0%≤N≤0.015%; 0%≤Al≤0.1%; 0.03%≤Mo≤0.5%; 0%≤Cu≤0.5%; 0.04%≤Nb≤0.15%; 0.01%≤Ti≤0.1%; 0%≤V≤0.5%; 0.0015%≤B≤0.004%; the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel having microstructure including in area fraction, 55% to 85% of Martensite, 20% to 45% of Auto-tempered Martensite, 0 to 10% Residual Austenite and, wherein cumulated amounts of Auto-tempered martensite and martensite is at least 90%.
Claims18
A steel for forging mechanical parts having a composition comprising the following elements, expressed in percentage by weight:
- 0.04%≤C≤0.28%;
- 1.2%≤Mn≤2.2%;
- 0.3%≤Si≤1.2%;
- 0.5%≤Cr≤1.5%;
- 0.01%≤Ni≤1%;
- 0%≤S≤0.06%;
- 0%≤P≤0.02%;
- 0%≤N≤0.015%;
- and optionally one or more of the following elements
- 0%≤Al≤0.1%;
- 0.03%≤Mo≤0.5%;
- 0%≤Cu≤0.5%;
- 0.04%≤Nb≤0.15%;
- 0.01%≤Ti≤0.1%;
- 0%≤V≤0.5%;
- 0.0015%≤B≤0.004%;
- a remainder of the composition being iron and unavoidable impurities caused by processing,
- a microstructure of the steel consisting of, in area fraction, 55% to 80% of Martensite, 20% to 45% of Auto-tempered Martensite, 0 to 10% Residual Austenite and, wherein a cumulated amount of Auto-tempered martensite and martensite is at least 90%.
Dependencies are inferred from the claim text.