| 摘要 |
The invention relates to a steel part, the composition of the steel of which comprises, the contents being expressed by weight: 0.040%≦C≦0.100%; 0.80%≦Mn≦2.00%; Si≦0.30%; S≦0.005%; P≦0.030%; 0.010%≦Al≦0.070%; 0.015%≦Nb≦0.100%; 0.030%≦Ti≦0.080%; N≦0.009%; Cu≦0.100%; Ni≦0.100%; Cr≦0.100%; Mo≦0.100%; and Ca≦0.006%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the microstructure of the steel consisting of at least 75% equiaxed ferrite, martensite in an amount not less than 5% but not exceeding 20%, and bainite in an amount not exceeding 10%. |
