Tough ultra-strength stainless steel and method for manufacturing the same

Abstract

The invention discloses a high-flexibility high-strength stainless steel and a method for making the same, wherein the method comprises the following steps of: 1) preparing parent alloy, the chemical compositions by weight percentage of which are: less than or equal to 0.03 percent of C, less than or equal to 0. 10 percent of Mn, less than or equal to 0.10 percent of Si, less than or equal to 0.002 percent of S, less than or equal to 0.006 percent of P, 6.0 to 13.0 percent of Cr, less than or equal to 0.05 percent of Al, less than or equal to 0.10 percent of Cu, less than or equal to 0.05 percent of Ti, the balance Fe and unavoidable impurities; 2) melting an electrode with a vacuum induction furnace, in which the parent alloy is prepared with pure iron, nickel, and other metal material for melting the electrode; 3) vacuum consumable remelting, at a melting speed of between 180 and 220 Kg / h; 4) forging, in which steel ingots are heated at a temperature of 1180+-20 DEG C, with the temperature maintained for 3 to 6 hours, and are upset and drawn twice, and the forging temperature is above 850 DEG C. The stainless steel of the invention has matched combination properties including 1800Mpa strength, 1400 Mpa yield strength, 50J impact ductility, more than 100 Mpa fracture toughness.

Description

Technical field [0001] The invention relates to stainless steel material technology, in particular to strong and tough ultra-high-strength stainless steel and a manufacturing method thereof. Background technique [0002] At present, domestic and even international aerospace advanced precision machines have many parts (such as high-load bearing parts, rolling element parts, high-pressure shells, fasteners, etc.) that are matched with ultra-high strength and sufficient toughness. High-strength steel. [0003] The mechanical properties of high-strength structural steel can meet the requirements, but the rust resistance and stress corrosion fracture toughness are very poor, which seriously affects the storage and service life of steel and parts. Such materials include low-alloy, medium-alloy and high-alloy structural steels. The chromium content of various materials does not exceed 5%, and there is no corrosion resistance. [0004] High-strength stainless steel, mainly precipitation ...

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to provide a kind of strong toughness ultra-high strength stainless steel and its manufacturing method, by adopting the technical measures of optimizing chemical composition design, strengthening double vacuum smelting to improve purity and large forging ratio forging, solving the existing American similar material AFC -77 Low toughness and CSS-42L low yield ratio make the strength reach 1800Mpa; the yield strength reaches 1400MPa; the impact toughness reaches 50J;

Images