16-03-2017 дата публикации
Номер: US20170073792A1
A hot-formed steel sheet member having a chemical composition includes, in terms of mass %, from 0.08 to 0.16% of C, 0.19% or less of Si, from 0.40 to 1.50% of Mn, 0.02% or less of P, 0.01% or less of S, from 0.01 to 1.0% of sol. Al, 0.01% or less of N, from 0.25 to 3.00% of Cr, from 0.01 to 0.05% of Ti, from 0.001 to 0.01% of B, and a reminder consisting of Fe and impurities, wherein a total volume fraction of martensite, tempered martensite, and bainite is 50% or more, and a volume fraction of ferrite is 3% or less, an average grain size of prior γ grains is 10 μm or less, and a number density of residual carbides which are present is 4×10per mmor less. 1. A hot-formed steel sheet member having a chemical composition consisting of , in terms of mass % , from 0.08 to 0.16% of C , 0.19% or less of Si , from 0.40 to 1.50% of Mn , 0.02% or less of P , 0.01% or less of S , from 0.01 to 1.0% of sol. Al , 0.01% or less of N , from 0.25 to 3.00% of Cr , from 0.01 to 0.05% of Ti , from 0.001 to 0.01% of B , from 0 to 0.50% of Nb , from 0 to 2.0% of Ni , from 0 to 1.0% of Cu , from 0 to 1.0% of Mo , from 0 to 1.0% of V , from 0 to 0.005% of Ca , and a remainder consisting of Fe and impurities ,wherein a total volume fraction of martensite, tempered martensite, and bainite is 50% or more, and a volume fraction of ferrite is 3% or less,an average grain size of prior γ grains is 10 μm or less, and{'sup': 3', '2, 'a number density of residual carbides which are present is 4×10per mmor less.'}2. The hot-formed steel sheet member according to claim 1 , wherein the chemical composition comprises one or more selected from the group consisting of claim 1 , in terms of mass % claim 1 , from 0.003 to 0.50% of Nb claim 1 , from 0.01 to 2.0% of Ni claim 1 , from 0.01 to 1.0% of Cu claim 1 , from 0.01 to 1.0% of Mo claim 1 , from 0.01 to 1.0% of V claim 1 , and from 0.001 to 0.005% of Ca.3. The hot-formed steel sheet member according to claim 1 , wherein a value of a cleanliness level of ...
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