Method for reducing carbon segregation of medium carbon steel round billet

Abstract

The invention provides a method for reducing carbon segregation of a medium carbon steel round billet. Specifically, continuous casting process requirements are that the drawing speed is 0.7 to 0.75 m / min; the superheat degree is 15 to 25 DEG C; the M-EMS current is 170 to 180 A; the M-EMS frequency is 3 HZ; the F-EMS current is 400 to 420 A; the F-EMS frequency is 8 HZ; the electromagnetic stirring time at a solidification end is set to rotate forward for 8 seconds, stop for 3 seconds, and rotate backward for 8 seconds; and the specific water flow in secondary cooling is 0.25 L / Kg. Compared with the prior art, the carbon segregation range of the medium carbon steel round billet is reduced by exploring and optimizing the basic process of continuous casting without secondary cooling and electric stirring, so that the project input cost is low; relevant theoretical basis is provided for solving a strip structure of a rolled material; moreover, the method is simple in process route and facilitates operation in the field. Through the popularization of the technology, the carbon segregation of the medium carbon steel round billet is effectively reduced; and the product quality stabilityis improved.

Description

technical field [0001] The invention belongs to the field of metallurgy, and in particular relates to a method for reducing carbon segregation of medium-carbon steel round billets. Background technique [0002] The quality problems of continuous casting slabs include physical defects and chemical defects. Among these defects, the composition segregation of chemical defects is more difficult to control. The carbon segregation in the slab will be inherited to the subsequent processes such as rolling and heat treatment. There are different degrees of low-magnification segregation defects on the surface of the material, that is, the uniform distribution of chemical components. Such defects will affect machining, heat treatment, and dimensional stability, thereby affecting the performance and life of the finished product, and even scrapping. [0003] For the problem of carbon segregation, billets / rectangles are generally solved by online reduction technology or forced cooling t...

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Problems solved by technology

[0004] Many metallurgists have devoted themselves to the research on the formation mechanism and control measures of carbon segregation at the CET transition position of the bloom continuous caster. Although the mechanism of carbon segregation has been clarified for a long time, due to the different tooling of different enterprises, the adjustment direction is also very different. High-temperature diffusion is used to control carbon segregation, some increase secondary cooling electromagnetic stirring to control carbon segregation, some use strong cooling to increase columnar crystals to control carbon segregation, and some use weak cooling to increase equiaxed crystals to control carbon segregation, but most of them are concentrated in industry In the test stage, the cost is huge, especially in the screening and coordination of multiple control parameters, the test exploration cycle is long, and it is not easy to implement

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