| 摘要 |
PROBLEM TO BE SOLVED: To provide an age hardening type bainitic non-heat-treated steel capable of obtaining a higher fracture toughness value compared with a conventional one.SOLUTION: An age hardening type bainitic non-heat-treated steel includes, by mass%, C:0.06-0.35%, Si:0.01-2.00%, Mn:0.10-3.00%, S:0.001-0.200%, Cu:0.001-2.00%, Ni:0.40-3.00%, Cr:0.10-3.00%, Mo:0.10-1.00%, V:0.10-1.00%, s-Al:0.001-0.100%, and the balance Fe with inevitable impurities; and has such a composition that a value in Expression (1) of 3×[C]+10×[Mn]+2×[Cu]+2×[Ni]+12×[Cr]+9×[Mo]+2×[V] satisfies 20 or more and a value in Expression (2) of 1.66×[C]+0.18×[Si]+0.27×[Mn]+0.09×[Ni]+0.32×[Cr]+0.34×[Mo]+0.44×[V] satisfies 0.82 or more. (In expression (1) and expression (2), [ ] represents the content of the element of [ ] in mass%.) |
