Steel plate made of bainite structure high-strength toughness structural steel Q550D(E) and production method thereof

Abstract

The invention discloses a steel plate made of bainite structure high-strength toughness structural steel Q550D(E) and a production method thereof. The steel plate comprises the following chemical ingredients in percentage by mass: 0.05-0.15 percent of C, 0.10-0.40 percent of Si, 1.40-1.65 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.30 percent of micro alloying element (V+Nb+Ti+Mo+B), less than or equal to 0.050 percent of Als and the balance of Fe and residual elements. The production method comprises the following steps of: pretreating molten iron; smelting in a converter; refining in an LF (Ladle Furnace); carrying out VD (Vacuum Degassing); carrying out continuous steel casting; heating; carrying out TMCP (Thermo Mechanical Control Process) rolling; controlling cold; and stacking for slow cooling. In the invention, in the rectifying and reforming processes from molten steel treatment to steel plate stacking for slow cooling and rectification, a strict process point control standard is formulated and executed, thus the mass quality of a product is good, and the margin performance is larger, wherein the yield margin is 50-100MPa, the tensile margin is 30-60MPa, the elongation margin is 2-4 percent, and the impact property reaches the level of -60 DEG C; and the TMCP process is adopted for producing qualified products at a time without quenching and tempering, thus the production cost is greatly reduced.

Description

technical field [0001] The invention relates to steel products, in particular to a Q550D (E) steel plate of high-strength and toughness structural steel with bainite structure and a production method thereof. Background technique [0002] High-strength structural steel Q550D (E) is a low-alloy high-strength structural steel, which has the characteristics of high strength, good toughness, excellent low-temperature toughness, good processing performance and welding performance. Mainly used in engineering machinery, coal mining machinery, shipbuilding and steel structure and other fields. In recent years, the application of low-alloy high-strength steel has become more extensive, and there have been a lot of researches on this in China. However, the production cost of high-strength Q550D (E) steel plate remains high due to its difficulty in production and special requirements for process equipment. Some domestic steel mills use TMCP+RPC+T for production, and the process is com...

AI Technical Summary

Problems solved by technology

However, the production cost of high-strength Q550D (E) steel plate remains high due to its difficulty in production and special process equipment requirements. Some domestic steel mills use TMCP+RPC+T for production, and the process is complicated, and some steel materials are in quenched and tempered state. Delivery, the steel plate undergoes two heat treatment processes of quenching and tempering, which not only requires strict heat treatment equipment, but also increases the production cycle and production cost

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