Heat treatment process of low alloy high-strength steel with yield strength of 690 MPa

Abstract

The invention provides a rapid heat treatment process of low alloy high-strength steel with yield strength of 690 MPa. The contents of alloy elements in the steel (percentage by weight) are as follows: the content of Mn (Manganese), Cr (Chromium), Ni (Nickel), Cu (Copper) and Mo (Molybdenum) is 2.05-2.6% while the content of Nb (Niobium) and Ti (Titanium) is 0.045-0.085 %. The heat treatment is carried out through rapid heating and quenching; and the method comprises the steps of heating the steel to 960 DEG C at a heating speed of no more than 50 DEG C / min, wherein the austenitizing heat preservation time is 3-5 minutes; and then hardening the steel to the room temperature at a cooling speed of 30-300 DEG C / s. The rapid heat treatment process of the low alloy high-strength steel with yield strength of 690 MPa, provided by the invention, has the following advantages that: the heating and heat preservation time of the heat treatment is reduced through increasing the heating speed and preserving the heat for a short time at a higher austenitizing temperature while the mechanical property of the steel is assured to the benefit of saving energy consumption and improving the productionefficiency; and references can be also provided to the heat treatment of low alloy high-strength steels with other strength levels.

Description

technical field [0001] The invention provides a rapid and high-efficiency heat treatment process for low-alloy high-strength steel with a yield strength of 690 MPa, and belongs to the technical field of metal material heat treatment. Background technique [0002] Improving the mechanical properties of alloy steel through heat treatment is a common method in the field of metallurgy. Heat treatment can affect the structure and mechanical properties of steel. [0003] The quenching of steel is to heat the steel to the critical temperature (Ac 3 or Ac 1 ) above, after holding for a certain period of time to make it austenitized, it is a process of cooling at a cooling rate greater than the critical cooling rate. The main purpose of quenching is to obtain as much martensite as possible in the austenitized workpiece and tempering at different temperatures to obtain various required properties. For the quenching process, in order to achieve quenching, the steel must first be hea...

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Problems solved by technology

[0009] The above-mentioned patents (applications) generally have the following deficiencies: 1. the process is complicated

② Long heating and holding time during heat treatment, high energy consumption and low production efficiency

Therefore, although improving the mechanical properties of alloy steel through heat treatment is a common method in the field of metallurgy, how to choose appropriate heat treatment conditions and obtain good heat treatment effects is still a big problem.