Method for enhancing low temperature impact toughness of steel plate applied to railway

Abstract

The invention provides a method for enhancing low temperature impact toughness of a steel plate applied to a railway. The method aims at the steel plate applied to a railway, wherein the steel plate is not added with a lot of alloy elements and a carbon equivalent of a composition system is kept lower than 0.45. Under nitrogen protection, heating is conducted with a radiant tube, medium-temperature tempering is conducted on the steel plate, and surface oxidation of the steel plate is avoided; through accurate control of tempering technological parameters such as a furnace temperature, a temperature rise rate and thermal preservation time, the steel plate can be heated uniformly, and non-carbide forming elements can be gradually enriched and nodulized, so former unstable carbides can be gradually replaced by more stable carbides; homogeneity of organizational properties is ensured; and stability of the organizational structure is effectively enhanced. In this way, low temperature impacttoughness of a rolled-state delivery thick plate can be effectively enhanced; a performance percent-of-pass index is increased; an amendment amount of steel plates caused by nonconforming performancecan be reduced; and cost control in batched production can be guaranteed.

Description

technical field [0001] The invention belongs to the technical field of iron and steel manufacturing, and in particular relates to a method for improving the low-temperature impact toughness of steel plates for railways. Background technique [0002] Most of the railway steel is delivered in the rolling state, and the stability of the performance and structure of the steel plate in the rolling state requires excellent production equipment and long-term production experience. In particular, low temperature impact toughness is a difficult point in performance control, and performance fluctuations often occur during mass production. There are mainly the following points: 1. The qualified rate of low temperature impact toughness is not controlled, and the performance of the steel plate does not meet the technical requirements, causing certain economic losses after the judgment is changed. 2. In order to improve low-temperature impact toughness, the addition of alloy content is i...

AI Technical Summary

Problems solved by technology

Especially low-temperature impact toughness is a difficult point in performance control, and performance fluctuations often occur during mass production

There are mainly the following points: 1. The qualified rate of low temperature impact toughness is not controlled, and the performance of the steel plate does not meet the technical requirements, causing certain economic losses after the judgment is changed

2. In order to improve low-temperature impact toughness, the addition of alloy content is increased, resulting in a sharp increase in production costs

3. The increase of alloy content leads to the increase of carbon equivalent in the composition system, which deteriorates the welding performance of the steel plate and affects the customer's subsequent processing and forming

Due to the particularity of railway steel, there is currently no means to effectively improve its low temperature impact toughness

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