Heat treatment process for improving strength and low-temperature impact toughness of anti-corrosion steel casting

A technology of low temperature impact toughness and steel castings, which is applied in the field of production of corrosion-resistant steel castings for bridge supports, can solve the problems of yield strength not reaching 400MPa level, tensile strength not reaching 550MPa level, etc. Effect

CN106834636AActive Publication Date: 2017-06-13RAILWAY ENG RES INST CHINA ACADEMY OF RAILWAY SCI +4
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2017-06-13

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Abstract

The invention provides a heat treatment process for improving the strength and low-temperature impact toughness of an anti-corrosion steel casting. A hardening and tempering process is adopted for treatment. The heat treatment process comprises the steps that 1, cast steel is subjected to high-temperature quenching in a heating furnace, the quenching temperature ranges from 880 DEG C to 950 DEG C, heat preservation is carried out for 4-6 h, the cast steel is put into water to be cooled, and the in-water time is smaller than or equal to 1 min; and 2, tempering treatment is carried out, the tempering temperature ranges from 660 DEG C to 710 DEG C, heat preservation is carried out for 4-6 h, and then the cast steel is subjected to air cooling to the room temperature. The heat treatment process has the beneficial effects that the steel casting obtained through the heat treatment process is high in strength, plasticity and impact toughness; and the plasticity index is not lower than the widely-used ZG270-500 requirement, meanwhile, the yield strength is larger than or equal to 400 MPa, the tensile strength is larger than or equal to 550 MPa, and the impact toughness of -40 DEG C exceeds 30 J.
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Description

technical field

[0001] The invention belongs to the technical field of production of corrosion-resistant steel castings for bridge supports, and particularly provides a heat treatment process for improving the strength and low-temperature impact toughness of corrosion-resistant steel castings with a Cr content of 3-5%. Background technique

[0002] The bridge bearing is an important structural component connecting the superstructure and substructure of the bridge. It can reliably transmit the reaction force and deformation (displacement and rotation angle) of the superstructure of the bridge to the substructure of the bridge. Therefore, the national standard has clear requirements on the mechanical properties of steel castings for bridge supports, and its material is generally ZG270-500. The mechanical properties of cast carbon steel parts for general engineering in GB / T 11352 are shown in Table 1, but because The strength of cast carbon steel parts in the standard is low, w...

Examples

Embodiment Construction

[0026] Preferred embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the application and are used together with the embodiments of the present invention to explain the principles of the present invention.

[0027] See Tables 2, 3, and 4 for the main chemical components, heat treatment process, and mechanical properties of the embodiments of the present invention and comparative examples.

[0028] Each embodiment of table 2 and comparative example main chemical composition (%)

[0029] test steel C Si mn P S Cu Cr Ni Al V Mo Example 1 0.10 0.50 1.38 0.005 0.006 0.39 3.14 1.44 0.12 - 0.04 Example 2 0.15 0.21 0.87 0.007 0.004 0.35 4.65 0.39 0.23 - - Example 3 0.08 0.65 0.79 0.008 0.005 0.57 4.90 0.58 0.06 0.04 - Example 4 0.12 0.46 0.98 0.006 0.005 0.62 3.54 0.73 0.18 - ...