Preparation method of ultra-high strength 40CrMnSi2Ni2MoVA ultra-large size forging billet

By combining vacuum induction furnace smelting and vacuum arc remelting furnace processes, the problems of chemical composition and microstructure uniformity of ultra-large forging billets have been solved, enabling high-performance production of ultra-high strength 40CrMnSi2Ni2MoVA ultra-large forging billets, meeting the requirements of load-bearing structural components for large aircraft.

CN117867361BActive Publication Date: 2026-06-30FUSHUN SPECIAL STEEL SHARES +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
FUSHUN SPECIAL STEEL SHARES
Filing Date
2023-12-21
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

Existing technologies cannot effectively produce ultra-high strength 40CrMnSi2Ni2MoVA ultra-large forging billets that meet the requirements of load-bearing structural components for large aircraft, especially due to the problems of large ingot size, inclusions, and severe chemical composition segregation.

Method used

The process combines vacuum induction furnace smelting and vacuum arc remelting furnace smelting. Through precise batching, low-temperature casting, vacuum welding and staged heating control, the uniformity of chemical composition and microstructure is ensured, inclusion segregation is reduced, and the utilization rate and mechanical properties of steel ingots are improved.

Benefits of technology

It achieves comprehensive metallurgical quality standards for ultra-large forging billets that are comparable to those for smaller sizes. The inclusions and grain size in the steel are superior to existing technologies, meeting the high strength and toughness requirements of load-bearing structural components for large aircraft and reducing production costs.

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Abstract

This invention discloses a method for preparing ultra-high strength 40CrMnSi i2Ni i2MoVA ultra-large-sized forging billets, achieving comprehensive metallurgical quality that fully meets the technical specifications for small-sized round bars. Vacuum induction smelting precisely controls the carbon, manganese, sulfur, and titanium content in the steel, reducing the generation and accumulation of inclusions; refining employs low-vacuum stirring to continuously improve the purity of the molten steel; during casting, low-temperature, low-segregation protective casting technology is used to achieve uniform chemical composition in the ultra-large-sized electrode billets; it enables two materials from one ingot, improving the ingot utilization rate; and a high-expansion-low-low-low control technology is used for the ingot to obtain a uniform fine-grained structure. The beneficial effects of this invention are: solving the problems of low-magnification microstructure uniformity, chemical composition, and inclusion segregation in large-sized ingot forging billets; achieving excellent metallurgical quality in all directions (longitudinal, transverse, and high-axis), fully meeting the technical specifications for small-sized bars, while significantly increasing the service life of the forging billets.
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