Tempering heat treatment equipment and technique for bainite high-strength finish-rolled thread steel bars

Abstract

The invention discloses tempering heat treatment equipment and technique for bainite high-strength finish-rolled thread steel bars and belongs to the technical field of metal heat treatment equipment and techniques. The tempering heat treatment equipment and technique are used for conducting batched tempering heat treatment on the bainite high-strength finish-rolled thread steel bars. According to the technical scheme, the tempering heat treatment equipment adopts the structure of a double-station trolley and a double-station heat preservation hood. Alternate loading heat treatment can be achieved through the double-station trolley, the heat preservation time in a heat treatment furnace within a certain temperature range can be shared by the double-station heat preservation hood, the heat treatment efficiency of the heat treatment furnace is greatly improved through the alternate heat treatment process, energy resources are saved, and batch production of products is achieved. According to the heat treatment technical method, on the basis that uniform biphase structures and reasonable strength and toughness matching of the bainite high-strength finish-rolled thread steel bars are guaranteed, and the residual stress of the structures and the sensitivity of a hydrogen-induced crack are reduced, small-batch production can be organized, heat treatment of short materials is achieved with a certain fixed length range, and the application is wide and flexible.

Description

technical field [0001] The invention relates to batch tempering heat treatment equipment and a process method for bainitic high-strength finish-rolled threaded steel bars, and belongs to the technical field of metal heat treatment equipment and processes. Background technique [0002] At present, there are two kinds of production steel types and processes for high-strength finish-rolled threaded steel bars (including PSB830, PSB930 and PSB1080 grades), which are widely used in large-scale projects such as high-speed railways, bridges and super high-rise buildings. The 40Si2MnV steel grade is widely used in China, and the production process of on-line quenching and tempering is used to produce high-strength finish-rolled threaded steel bars. The production process of this steel grade is complex, with high requirements for production equipment and strict requirements for production process control. The other is to properly adjust its composition on the basis of 30Mn2Si steel a...

AI Technical Summary

Problems solved by technology

The 40Si2MnV steel type is widely used in China, and the production process of on-line quenching and tempering is used to produce high-strength finish-rolled threaded steel bars. The production process of this steel type is complicated, and it has high requirements for production equipment and strict requirements for production process control.

The other is to properly adjust its composition on the basis of 30Mn2Si steel and add V, Cr, Ti and other alloying elements to produce high-strength finish-rolled threaded steel bars. This technology has no special requirements for production equipment, and it can be achieved by air cooling after rolling. requirements, the process control is simple, but the high-strength finish-rolled rebar produced by this technology is air-cooled after rolling to obtain a multi-phase structure of bainite + martensite. Brittle fracture occurs, therefore, the high-strength finish-rolled rebar must undergo subsequent stress-relief heat treatment

Existing heat treatment and tempering equipment and processes are not satisfactory for batch tempering heat treatment of bainitic high-strength finish-rolled rebars, which directly affects the performance of bainitic high-strength finish-rolled rebars, and urgently need to be improved

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