A lanthanum cerium rare earth alloy mold steel smelting process

Abstract

The invention relates to a lanthanum-cerium rare-earth alloy mold steel smelting process. The weight ratio of the composite rare earth is lanthanum:cerium=35:65; The method is to add the molten steel through the intermediate vacuum-sealed silo when the VD vacuum degree is less than or equal to 0.67mbr and keep it until the 18th minute; the condition for adding the compound rare earth is that the carbon weight percentage content of the initial refining steel is not less than 0.05%; according to The composition of refining slag in weight percent is CaO: 0.47‑58%, Al 2 o 3 =25‑32%, SiO 2 =8-10%; Dissolved oxygen before VD is not more than 5ppm, and the optimal control is below 3.5ppm; feed aluminum before VD, do not feed aluminum after VD, control the aluminum content to 0.015-0.025% according to the weight percentage, and can obtain low oxygen content , A more refined and evenly distributed inclusion control level, a finer structure control level, and can improve material properties, so that the impact toughness of ordinary die steel can be increased by 30%, meeting the requirements of high-quality die steel.

Description

technical field [0001] The invention belongs to the technical field of compound rare earth alloying smelting process design of die steel in iron and steel smelting, and specifically relates to a method that can obtain low oxygen content, a more refined and evenly distributed inclusion control level, a refined structure control level, and can Improve the performance of materials, especially the smelting process of lanthanum-cerium rare earth alloy die steel with impact toughness increased by more than 30%. Background technique [0002] Relying on the abundant rare earth resources in China, many metallurgical research institutes and steel plants are continuing to study the application of rare earths in iron and steel metallurgy. According to the current research results, the main role of rare earth in steel is to reduce the oxide content, purify molten steel, refine inclusions and structures, and promote their uniform distribution, thereby ultimately improving the performance ...

AI Technical Summary

Problems solved by technology

At present, a variety of rare earth alloys have been developed and applied in different steel types. However, in order to continue to improve the quality and performance of materials, the original technology has been difficult to continue to make breakthroughs. Therefore, it is very important to further study rare earth to improve the performance of steel. Beneficial, among them, on the basis of the original process technology of H13 die steel, research on the types of rare earths suitable for application, adding conditions of use and post-manufacturing technology can achieve obvious results, so it is urgent to design a set of rare earths that can improve impact energy and apply them to H13 die steel technical solutions in