40Mn2B alloy structural steel material

Abstract

The invention discloses a 40Mn2B alloy structural steel material, which is used for manufacturing alloy structural steel with high hardenability and low hardening break sensitivity. The 40Mn2B alloy structural steel material comprises the following chemical components in percentage by weight: 0.37-0.42 percent of C, 0.17-0.37 percent of Si, 1.40-1.70 percent of Mn, 0.20-0.60 percent of Cr, 0.0010-0.0035 percent of B, 0.015-0.045 percent of Ti, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, less than or equal to 0.06 percent of Mo, less than or equal to 0.15 percent of Ni and less than or equal to 0.25 percent of Cu. The hardness of the 40Mn2B alloy structural steel material can reach J13 / 50-60 HRC, the tempering hardness of 217-269 HB can be reached in a normalized condition, the effective hardened layer depth of 10-16mm can be achieved for shaft type parts, the cost is lower than that of the 42CrMo material, the hardening break sensitivity is low, and the thermal treatment processibility is good.

Description

technical field [0001] The invention relates to the technical field of metal material preparation, in particular to an alloy structural steel material suitable for manufacturing high hardenability and low quenching crack sensitivity. Background technique [0002] At present, among the medium-carbon alloy structural steels used for auto parts in China, 40MnB, 40Cr, and 42CrMo steels are mainly used. 40MnB and 40Cr steels have low hardenability, and it is difficult to achieve an effective hardening layer depth of more than 10mm for induction quenching with a diameter of φ60-80. , there is the defect of insufficient hardenability, which cannot meet the technical requirements of high-level deep induction hardening; 42CrMo steel has high hardenability, and the effective hardened layer depth can reach the requirements of more than 10mm, and its hardenability meets the high-level deep induction hardening technology. Requirements, but the cost is high, and Mo steel has the risk of e...

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Problems solved by technology

[0003] In order to overcome the lack of hardenability or easy cracking of medium carbon alloy steel in the production of automobile parts, the purpose of the present invention is to provide a 40Mn2B alloy structural steel material, which is improved on the basis of the original 40MnB , not only greatly improves the hardenability and meets the requirements of induction hardening layer depth, but also the quenching cracking sensitivity is significantly lower than 42CrMo, and the cost is low