Engineering steel with excellent low-temperature impact toughness and lamellar tear resistance in core and production method thereof

Abstract

The invention relates to a production method of an engineering steel material with excellent core low-temperature impact toughness and lamellar tearing resisting performance. The engineering steel material comprises the following main components in percentage by weight: 0.030-0.010 percent of carbon, 1.20-1.60 percent of manganese, 0.10-0.35 percent of silicon, 0.015-0.03 percent of niobium, 0.005-0.020 percent of titanium, 0.020-0.040 percent of total aluminum, and not less than 0.10 percent of calcium / total aluminum; the engineering steel material also comprises the following residual components in percentage by weight: not more than 0.006 percent of nitrogen, not more than 0.004 percent of oxygen, not more than 0.015 of phosphorus, not more than 0.006 percent of sulfur, not more than 0.04 percent of arsenic, not more than 0.03 percent of stannum and not more than 0.02 percent of antimony; and except the main components and the residual components, the balance is ferrum. According to the engineering steel material and the production method provided by the invention, without adding nickel, vanadium and other expensive alloying elements and without adopting offline quenching and tempering treatment and other expensive equipment, the steel material with the yield strength of not less than 420 Megapascal and the excellent core toughness and lamellar tearing resisting performance can be obtained by only adopting a niobium and titanium micro-alloyed low carbon-manganese-niobium-titanium component system and fitting with an online quenching and tempering process.

Description

technical field [0001] The invention relates to a metallurgical steel material, more specifically, the invention relates to an engineering steel material with a low C-Mn-Nb-Ti composition system and a production process thereof. Background technique [0002] With the development of my country's industrial economy, the requirements for high-grade and high-performance steel grades are gradually increasing, which drives the research and development of domestic high-performance steel into a new stage. Among them, bridge structures, high-rise buildings, offshore platforms, and ship hull structures usually use low-alloy high-strength steel with a yield strength of 420MPa; and because the application of the above-mentioned structures requires the steel plate to bear a certain stress in the thickness direction, such as the impact of the center of the steel plate and Poor tear resistance in the laminar state is likely to cause structural damage. Therefore, these harsh engineering env...

AI Technical Summary

Problems solved by technology

[0011] In terms of alloying, various processes use a large amount of microalloying elements. In addition to Nb and Ti, Cu, Ni, Cr, V, B, etc. are also added, which increases the cost of steelmaking, and the addition of a large number of microalloying elements affects the billet. Surface quality, such as the addition of Cu will cause cracks in the steel plate; the addition of Ni will cause the iron oxide scale to be difficult to remove. When Ni is contained in the steel, if oxidation occurs, the concentrated part of Ni will bulge, and the interface shape will be uneven, causing the scale to peel off. sexual deterioration

[0012] In terms of technology, either use complex pure steel technology, such as rare earth treatment, Zr treatment, etc., but it is difficult to achieve; or use normalizing heat treatment, but in order to compensate for the strength loss of the structure change after normalizing heat treatment, a large amount of microalloying elements need to be added; or Offline quenching and tempering process is adopted, but because offline quenching and tempering treatment requires expensive equipment such as quenching machines, two processes of reheating and quenching are added, which increases the production cycle and production cost accordingly, and for steel mills that are not equipped with offline quenching and tempering production lines unable to produce

This not only restricts the development and progress of the majority of iron and steel production enterprises, but also is not conducive to the research and development of 420MPa strength grade steel products.

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