Non-post-heat treated steel and non-post-heat treated steel member
AssigneeNippon Steel & Sumitomo Metal Corporation
InventorsNaoyuki Sano, Tatsuya Hasegawa
Life of this patent
Estimating the term…
Abstract
Non-post-heat treated steel contains: in mass %, C: 0.27 to 0.40%, Si: 0.15 to 0.70%, Mn: 0.55 to 1.50%, P: 0.010 to 0.070%, S: 0.05 to 0.15%, Cr: 0.10 to 0.60%, V: 0.030% or more and less than 0.150%, Ti: more than 0.10%, not more than 0.200%, Al: 0.002 to 0.050%, and N: 0.002 to 0.020%, and optionally one or more of Cu≦0.40% and Ni≦0.30%; the balance being Fe and impurities, wherein [Ti]−3.4[N]−1.5[S]<0, and 0.60<[C]+([Si]/10)+([Mn]/5)+(5[Cr]/22)+(33[V]/20)−(5[S]/7)<0.80. The steel can be used to make a high fatigue strength connecting rod for automobile engines which is fracture-split from a hot forged shape. The non-post-heat treated steel member can have vERT of 1.0 to 7.0 J/cm2, and σw≧450 MPa.
Claims4
Non-post-heat treated steel having a chemical composition comprising:
- in mass %, C:
- 0.27 to 0.40%, Si:
- 0.15 to 0.70%, Mn:
- 0.55 to 1.50%, P:
- 0.010 to 0.070%, S:
- 0.05 to 0.15%, Cr:
- 0.10 to 0.60%, V:
- 0.030% or more and less than 0.150%, Ti:
- more than 0.100%, not more than 0.200%, Al:
- 0.002 to 0.050%, and N:
- 0.002 to 0.020%;
- the balance being Fe and impurities, wherein Et represented by Formula <1> is less than 0, and Ceq represented by Formula <2> is more than 0.60 and less than 0.80:
- Et=[Ti]−3.4 [N]−1.5[S] <1>
- Ceq=[C]+([Si]/10)+([Mn]/5)+(5[Cr]/22)+(33[V]/20)−(5[S]/7) <2>
- where a symbol of each element enclosed by [ ] in Formulas <1> and <2> denotes a content in mass % of the element in the steel.
Dependencies are inferred from the claim text.