Kipah-level bainite steel with ultrahigh yield ratio and manufacturing method of Kipah-level bainite steel

Abstract

The invention discloses a Gigaba-grade bainite steel with an ultrahigh yield ratio. The Gigaba-grade bainite steel comprises the following chemical elements in percentage by mass besides Fe: 0.12-0.24% of C, 0.12-0.24% of Si, 0.12-0.12% of Cr, 0.12-0.12% of Mo, 0.2 to 0.5 percent of Si; 1.3 to 2.0 percent of Mn; b: 0.001 to 0.004 percent of the total weight of the raw materials; cr is less than or equal to 0.4%, Nb is less than or equal to 0.06%, Ti is less than or equal to 0.1%, and Mo is less than or equal to 0.4%. In addition, the invention further discloses a manufacturing method and an annealing process for the steel. The annealing process comprises the following steps: (a) heating to a soaking temperature Ts of 840-900 DEG C at a heating rate of less than or equal to 50 DEG C / s in a heating section; (b) preserving heat for less than 5 minutes at a temperature Ts in a soaking section; (c) cooling to (Ts-80)-(Ts-140) DEG C at a first cooling rate of less than or equal to 15 DEG C / s in a slow cooling section; (d) cooling to (Ts-490)-(Ts-440) DEG C at a second cooling rate of more than or equal to (130-Q) DEG C / s in a rapid cooling section, Q = C * 180 + Si * 10 + Mn * 30 + Ni * 50 + Cr * 15 + Mo * 15 + B * 2000; the third cooling speed is larger than or equal to [(Q-80) / 12] and smaller than or equal to [(Q-80) / 8]; and (f) the strip steel is air-cooled to the room temperature in the air cooling section.

Description

Technical field [0001] The present invention relates to a steel species and a method of manufacturing the same, and more particularly to a geka-based Babystone steel and a manufacturing method thereof. Background technique [0002] Under "Green-Safety" new era concept, with the strength requirements of the car to structural parts and safety become higher and higher, JPP high-strength steel has become the most concerned car structural materials for major automakers. one. [0003] In recent years, more and more automotive structural parts (such as parts of the cabin and chassis system) require "zero deformation" to ensure the normal use of the car, which is proposed for the performance of the material. Quite high requirements require that their yield strength or flexor is higher than the higher. At present, high-yield strength or high-improvement is more and more extensive than the importance of automakers. [0004] The existing invention patent reflexive flexor is more than univer...

AI Technical Summary

Problems solved by technology

[0013] Therefore, how to obtain Gipa grade ultra-high-strength steel with a yield ratio ≥ 0.9 needs to break through a series of technical difficulties such as the above-mentioned first-level technical contradiction and the second-level technical contradiction, which cannot be realized in the existing patented technology

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