How to reduce delamination of low alloy steel plate

Low alloy steel plate has a broad application space in the market. In order to produce high-quality low alloy steel plates, many details need to be paid attention to in the production process. Delamination is one of the problems that often occurs in the production process of low alloy steel plate, but it is also possible to avoid delamination of low alloy steel plate by taking corresponding measures.

Smelting process. Reduce the impact of sulfides. The larger the size of the sulfide in the slab, the greater the harm to the low alloy steel plate. The size of the sulfide that affects the delamination of the medium and heavy plate is 5 μm. The sulfide smaller than this size is in a semi-fused state, and basically does not deform. Basically has no effect on stratification. To obtain fine sulfide inclusions, controlling the sulfur content in the steel and the shape of MnS is quite critical. When the sulfur content in the steel is reduced to 0.02% or even lower, it can effectively prevent delamination. In addition, the sulfide is fed to the calcium silicon wire to control the sulfide into a spherical or irregular angular particle shape. After rolling, it becomes an oval shape with less damage to delamination. Reduce the effects of component segregation. Reduce carbon content and manganese content, adopt low-phosphorus smelting process, reduce molten steel superheat, choose reasonable drawing speed and secondary cooling process system, adopt electromagnetic stirring and light pressure continuous casting technology to ensure good casting machine working condition, can effectively reduce segregation in the center of the casting slab.

Steel rolling process. During the rolling process, rolling with large reduction procedures is used to increase the stress and strain penetration rate, so that the defects generated in the slab are welded as much as possible, which is beneficial to reduce the delamination defects in the steel plate. Optimize the cooling process system of low alloy steel plate after rolling. When ACC water cooling, adjust the upper and lower water ratio reasonably, clean up the clogged nozzle, try to ensure that the low alloy steel plate is cooled uniformly, reduce the occurrence of abnormal structure, and reduce the internal stress of the low alloy steel plate. Ensure reasonable heating temperature and time of casting billet, and ensure sufficient solid solution of Nb, Ti and other elements.