High strength bolting steel with excellent delayed fracture resistance and cold working performance

Abstract

The name in religion belongs to the alloy steel domain, mainly is suitable above tensile strength 1200MOa, has good bears the detention break and cold finishing the performance high strength bolt steel. The steel concrete chemical composition (weight %) is: C0.25~~0.4%, Si is smaller than is equal to 0.1%, Mn0.4~~1.4%, P is smaller than is equal to 0.01%, S is smaller than is equal to 0.008%, Cr0.1-0.5%, Mo0.15~~0.35%, B0.0005~~0.003%, Ti0.01~~0.1%, RE0.005~~0.04%, Al0.005~~0.05%, N0.004~~0.01%, -odd is Fe. The steel concrete chemical composition (weight %) center also may join 0.01~~0.1% Nb, in Zr any a kind of or two kind of sums. The invention and the existing technology compare, this steel not only tensile strength very high, moreover bears the detention break and cold finishing the performance fine, the cost is low.

Description

technical field

[0001] The invention belongs to the field of alloy steel, and is mainly suitable for high-strength bolt steel with a tensile strength above 1200MPa and good delayed fracture resistance and cold working performance. Background technique

[0002] High-strength bolts are widely used in machinery, automobiles, bridges, construction and other industries. When the tensile strength of bolts made of quenched and tempered low-alloy steel exceeds about 1200MPa, the problem of delayed fracture becomes very prominent. Therefore, the tensile strength of high-strength bolts actually used at present is generally lower than 1200MPa. With the development of various production departments, higher and higher requirements are put forward for the materials used in the manufacture of various fasteners (such as bolts, screws, nuts, etc.). Some bolts for automobiles and construction machinery even require strengths above 1400MPa. In recent years, the research and development of st...