Preparation method of nano-structure strip martensitic ultra-high-strength steel plate

Abstract

The invention discloses a preparation method of a nano-structure strip martensitic ultra-high-strength steel plate. The steel plate comprises the following chemical components by weight percentage: 0.28 to 0.32 percent of C, 1.5 to 1.8 percent of Si, 1.5 to 1.7 percent of Mn, 1.0 to 1.3 percent of Cr, 0.9 to 1.1 percent of Ni, 0.6 to 0.8 percent of W, less than 0.02 percent of P, less than 0.02 percent of S, and the balance of Fe and inevitable impurities; the method comprises the following steps: smelting alloy steel with the chemical components through a vacuum induction furnace, casting the alloy steel subjected to smelting into steel ingots, slowly cooling the steel ingots to room temperature, heating and performing heat preservation to the steel ingots, performing hot rolling to the steel ingots after the steel ingots are discharged from the furnace, spaying water to cool the steel ingots to a supercooled austenite temperature zone, then rapidly performing one-pass rolling to the steel ingots, rapidly spraying water to cool the steel ingots to room temperature, and performing tempering on the steel ingots, so as to obtain the nano-structure strip martensitic ultra-high-strength steel plate. The method has the advantages that the preparation process is simple, the method is easy to realize on a plate rolling production line, the production efficiency is high, the cost is low, the tensile strength of the plate reaches 1850 to 2050MPa, and the percentage of elongation is 10 to 15 percent.

Description

technical field [0001] The invention relates to a method for preparing a steel plate. Background technique [0002] The main strengthening method of steel used in large quantities as a structural material is quenching to obtain a martensitic structure. Martensite in steel usually has two forms: one is lath martensite, and its internal substructure is dislocation; the other is needle lamellar martensite, and its internal substructure is twin. Lath martensite has high strength and high toughness, that is, it has good comprehensive mechanical properties, while needle-like martensite has high hardness and high strength, but its toughness is very low. Therefore, it is very meaningful to control the microstructure of lath martensite for components that require impact resistance and withstand high loads. Usually, the steel is quenched to obtain martensite accompanied by a small amount of retained austenite. Then, the thickness of lath martensite and the morphology, quantity and ...

AI Technical Summary

Problems solved by technology

However, the alloy composition claimed in the patent does not contain Mo or W, which is easy to cause temper brittleness; the Si content is low (<1 wt.%), which is not conducive to improving ferrite strength and tempering stability, and inhibiting carbide precipitation ; The process steps require more precise control of the finish rolling temperature to ensure that dynamic recrystallization occurs to refine the austenite grains, so as to obtain austenite with a grain size of <10 microns; no tempering treatment, the level of plasticity and toughness is still improved Space