Controlled cooling method of thick steel plates for machines

Abstract

The invention provides a controlled cooling method of thick steel plates for machines. The technological sequence of straightening first and then cooling is adopted, different cooling paths and cooling rates are used according to the difference of steel plate thicknesses H, and as for the steel plates with H is larger than or equal to 10mm and further smaller than 20mm, the technological path of straightening plus reverse laminar cooling is adopted; as for the steel plates with H is larger than or equal to 20mm and further smaller than 30mm, the technological path of straightening plus forwardlaminar cooling is adopted; and as for the steel plates with H is larger than or equal to 30mm and further smaller than 40mm, the technological path of straightening plus forward superfast cooling plus air cooling plus laminar cooling is adopted. Deformation stresses inside the steel plates can be released, the flatness of the steel plates is guaranteed, the plate shapes of the steel plates are effectively controlled, ferrite crystal grains are refined, the organization structure of each steel plate is improved, and evenness and stability of the steel plate properties are guaranteed. The method is simple and easy to implement, operation is convenient, energy consumption is small, production cost is low, and effects can be achieved immediately without any investment.

Description

technical field [0001] The invention belongs to the technical field of steel rolling technology, and in particular relates to a controlled cooling method of thick-gauge ultra-high-strength steel plates for machinery. Background technique [0002] At present, the development trend in the field of machinery is to use more and more high-strength and ultra-high-strength welded structural steels, and requires ultra-high-strength steel plates to have the characteristics of low cost, good welding performance, and high low-temperature impact toughness. Determined by the process flow, domestic medium and heavy plate manufacturers generally adopt the equipment layout form of rolling mill-laminar cooling device-leveler (of course, there are less than 10 domestic companies that have installed ultra-rapid cooling devices or online quenching devices. , but laminar flow cooling devices are generally used for production), so in the field of high-strength thick plate applications, for the st...

AI Technical Summary

Problems solved by technology

This production method has congenital defects such as insufficient cooling equipment capacity for high-strength mechanical steel plates with a thickness of more than 10mm, incomplete heat exchange of the steel plate, uneven temperature on the upper and lower surfaces of the steel plate, etc., which are reflected in the quality of the steel plate. Unstable pass rate

[0003] In order to overcome the above defects, some domestic medium and heavy plate production lines adopt the off-line quenching + tempering method to process and make up for it. However, due to the production process and procedures of this method, the energy consumption is large, and the production cost is high, the scope of use is limited, especially The scale used in large production is not large