High-toughness ultrahigh-strength D506A steel easy for rotary extrusion and easy to weld and preparation method thereof

Abstract

The invention relates to high-toughness ultrahigh-strength D506A steel easy for rotary extrusion and easy to weld and a preparation method thereof, belonging to the technical field of alloy steel. The steel comprises the following chemical components in percentage by weight: 0.32-0.38% of C, 0.50-5.50% of Cr, 0.5-3.5% of Ni, 0.2-2.20% of Si, 0.2-2.2% of Mn, 0.05-1.50% of Mo, 0-0.5% of V, no more than 0.2% of Nb and the balance of Fe and other inevitable impurity elements. Compared with the prior art, the steel has excellent comprehensive performance, high toughness (sigma b>=1800Mpa) and ultrahigh strength (KIC>=90MPam<1 / 2>), and also has excellent weldability, rotary extrusion performance and decarbonization resistance.

Description

technical field [0001] The invention belongs to the technical field of alloy steel, and in particular relates to a high-toughness, easy-spinning and easy-welding ultra-high-strength D506A steel and a preparation method thereof. with σ b ≥1800Mpa and K IC ≥90MPam 1 / 2 With high toughness and ultra-high strength, it has good spinning and welding processability. Background technique [0002] Prior to this, ultra-high-strength steel for high-pressure shells was a special type of ultra-high-strength steel. Due to the needs of the forming process, in addition to maintaining high strength and high toughness, it must be easy to obtain spheroidized structure, low carbon Equivalent and low volatile elements, in order to meet the spinning and welding process requirements. [0003] Early ultra-high-strength steels for high-pressure shells were concentrated on low-alloy ultra-high-strength steels due to cost issues, mainly including 30CrMnSi, 30CrMnSiNi2, 4130, D6AC, D406A, etc., but ...

AI Technical Summary

Problems solved by technology

[0003] Early ultra-high-strength steels for high-pressure shells were concentrated on low-alloy ultra-high-strength steels due to cost issues, mainly including 30CrMnSi, 30CrMnSiNi2, 4130, D6AC, D406A, etc., but the strength of these low-alloy ultra-high-strength steels is generally 1600MPa and below ; With the increase of pressure and the decrease of volume weight of high-pressure shell, maraging steel of higher strength level is widely used, the famous ones are C200, C250, C300, T250, etc., the strength is from 1600MPa to 2000MPa, but due to the price Advanced problems have not been able to promote the application

[0008] Although current low-alloy shell steels can provide σ b ≥1620Mpa, K IC ≥80MPam 1 / 2 However, compared with the current demand for components in the aerospace field, there is still a gap in the comprehensive performance of strength and fracture toughness. The strength and toughness are both low, which cannot meet the technical requirements.

Images