High carbon high silicon martensite stainless steel billet and preparation method thereof

Abstract

The invention provides a high carbon high silicon martensite stainless steel billet. The steel billet is characterized by comprising the following components by weight percent: 0.41-0.47% of C, 2.80-3.20% of Si, 0.50-0.80% of Mn, 8.50-9.20% of Cr, 0.30% or less of Ni, 0.028% or less of P, 0.005% or less of S, 0.20% or less of W, 0.20% or less of Mo, 0.15% or less of V, 0.015% or less of Nb, 0.015% or less of Ti, 0.010% or less of Al and the balance Fe and inevitable impurities. The invention also provides a preparation method of the high carbon high silicon martensite stainless steel billet. The method comprises the following steps: performing primary smelting with an electric arc furnace (EAF), performing argon-oxygen decarburization (AOD) smelting, refining with a low frequency (LF) furnace, performing continuous casting, annealing and rolling. The method of the invention has simple operation, can stably control the quality of the continuous casting billet, completely suppresse cracks, overcome the defect of concentration of stress and increase the casting yield and quality stability of the martensite stainless steel.

Description

technical field [0001] The invention relates to a method for smelting and casting stainless steel in the metallurgical industry, in particular to a method for smelting and billet continuous casting of high-carbon and high-silicon martensitic stainless steel. Background technique [0002] Continuous casting slabs can be divided into slabs, blooms, billets, round billets, special-shaped billets, etc. according to the cross-section, among which billets (referring to section size ≤ 180×180mm 2 Continuous casting slab) The casting slab produced by continuous casting is mainly used for rolling into bars, wires, section steel, flat steel, pipes and other varieties. Stainless steel is a common high-alloy steel. From the perspective of metallographic structure, it can generally be divided into austenitic stainless steel, ferritic stainless steel, martensitic stainless steel and duplex stainless steel. [0003] 4Cr9Si series steel belongs to high-carbon martensitic stainless steel, w...

AI Technical Summary

Problems solved by technology

[0006] In order to reduce the hidden danger of cracks and alleviate the central porosity and segregation, only a reasonable cooling rate for this steel type can be found, and the safety range of this cooling rate is very narrow, which is very prone to production accidents and quality accidents

At present, for ordinary high-carbon steels, the method of "low-temperature rapid casting" is mostly used to reduce the center porosity and segregation. It causes large fluctuations in production and is prone to cracks. Therefore, it is difficult to stabilize the control and the effect is often not obvious

[0007] For martensitic billets, the problem of cooling stress concentration in the rapid solidification of continuous casting slabs must be solved. The method of slow cooling (24 hours or more) of red billets is generally used on site, but for medium-high carbon martensite In other words, it also has a problem of time-effect stress. If the continuous casting slab is produced for a long time after being slowly cooled, and then heated and rolled, it is also prone to cracks

[0008] Due to the above factors, there are very few reports on similar production of martensitic valve steel 4Cr9Si series billet continuous casting, and no similar production patent technology can be found.

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