A low-segregation gas valve steel continuous casting slab and its manufacturing method

Abstract

The invention discloses a low segregation gas valve steel continuous casting billet and a manufacturing method thereof, and belongs to the field of low segregation continuous casting billet manufacturing. The manufacturing method of the low segregation gas valve steel continuous casting billet comprises the following steps that refined liquid steel is transported to a rotary table first, a tundishcovering agent is added after passing through a tundish, the liquid steel is then led into a crystallizer and casting powder of the crystallizer is added, the liquid steel is casted by a continuous casting machine after preliminary solidification and crystallization, and the casting speed of the during casting by the continuous casting machine is controlled at 1.00-1.50m / min. according to the manufacturing method, the cogging technology is simple, the production cost is reduced, special casting powder of the crystallizer, electromagnetic mixing and weak cold drawing steel process reduce the segregation of the continuous casting billet, finished free ferrite, network carbide and carbide particle size are improved, the thermal stress and structure transformation stress of the continuous casting billet are eliminated by slow cooling annealing, the continuous casting billet is prevented from cracking, and the percent of pass of the continuous casting billet is improved. In addition, the invention further relates to a low segregation gas valve steel continuous casting billet which is a material special for manufacturing high quality gas valves for internal combustion engines such as automobile engines.

Description

technical field [0001] The invention relates to the field of low-segregation continuous casting billet manufacturing, in particular to a low-segregation gas valve steel continuous casting billet and a manufacturing method thereof. Background technique [0002] The phenomenon of uneven distribution of the constituent elements in the alloy during crystallization is called segregation. During the solidification and crystallization process of molten steel, due to the fast cooling rate, the chemical components in the solidified metal have no time to diffuse, resulting in uneven distribution and segregation. [0003] 42Cr 9 Si 2 The steel contains 0.35-0.50% C, 2.0-3.0% Si, 8.0-10.0% Cr, the steel is a martensitic heat-resistant steel, has high thermal strength, microstructure stability and oxidation resistance and is tempered It has a small brittle tendency and is a special material for the manufacture of internal combustion engine gas valves, mainly used for the manufacture o...

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Problems solved by technology

[0004] In the prior art, 42Cr 9 Si 2 Billet production adopts die casting + 825 blooming mill to open the billet, which has many procedures, long cycle time and high cost, and the casting and cooling conditions of the die cast ingot steel ingot are limited. At the same time, the temperature range of the solid-liquid two-phase line of 42Cr9Si2 steel is wide, and the composition of the ingot is segregated during the solidification process. Large, it is difficult to improve in the subsequent processing, resulting in large segregation of the finished product, free ferrite, network carbide and carbide particle size exceeding the standard, etc.

[0005] At present, there are few relevant researches on the manufacturing method of low-segregation gas valve steel continuous casting slabs in China. The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art

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