Gradual solidification forming method for large steel ingot or steel billet

Abstract

The invention provides a gradual solidification forming method for a large steel ingot or steel billet. The gradual solidification forming method is based on the dispersed and accumulated principle ofadditive manufacturing; the large steel ingot or steel billet is subjected to divisional dispersed casting; and a steel ingot or a steel billet of the required shape and size is formed through gradual solidification and accumulation. The gradual solidification forming method comprises the following specific steps that molten metal is injected step by step by using different-tonnage casting ladlesinto crystallizers of different sizes for solidification; a steel ingot solidified in the previous step is adopted as an ingot core before solidification in the next step; an ingot core wrapping layer is continuously cast on the periphery of the ingot core; and the steel ingot of the target size is formed through circulating reciprocating gradual solidification and accumulation. By the adoption of such a technology, the production flexibility can be achieved; diversified products including a round billet, a square billet and other regular billets as well as irregular billets of which the diameters vary in the axial direction can be formed; the near-forming casting of shaft parts and the solidification forming of different-steel-grade steel ingots or steel billets can be achieved; the steel ingot property and quality can be improved, and the use can be expanded; and besides, the quantity and the extent of defects in a steel ingot or a steel billet can be remarkably reduced through gradual solidification, the follow-up processing can become relatively easy, the post-processing is even not needed, and the near forming can be achieved.

Description

technical field [0001] The invention relates to a progressive solidification forming method of a large steel ingot or billet, and belongs to the technical field of metal material forming. Background technique [0002] In recent years, China's heavy equipment manufacturing industry has developed rapidly, and the demand for large forgings is also very strong, especially in nuclear power equipment, which represents the highest level of large forgings. The steel used in such products is generally produced by large steel ingots through billeting and forging processes, and its quality is closely related to the quality of the steel ingots. In order to obtain high-quality forgings, the inherent quality defects in steel ingots such as segregation, shrinkage, and inclusions must be controlled. [0003] The traditional large steel ingot is formed by pouring molten metal into the ingot mold at one time, and then cooling and solidifying for a long time. The as-cast structure often has c...

AI Technical Summary

Problems solved by technology

For example, if the net weight of the generator rotor in electric power equipment is about 100t, it is necessary to prepare a huge steel ingot of 150t~300t with a diameter of about 3000mm to manufacture, and the metal utilization rate is very low.

In addition, for heavy steel ingots, due to the local concentration of non-metallic inclusions in the core of the steel ingot, the risk of scrapping the steel ingot is particularly high

However, there are certain limitations in improving the internal defects of these slabs by relying on electroslag metallurgy and electromagnetic stirring technology

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