Low-crack-sensitivity steel plate with yield strength of 960MPa and manufacturing method of low-crack-sensitivity steel plate

Abstract

The invention relates to a low-crack-sensitivity steel plate with yield strength of 960MPa, which comprises the following chemical components in percentage by weight: 0.06 to 0.10 percent of C, less than or equal to 0.20 percent of Si, 0.70 to 1.00 percent of Mn, 0.015 to 0.035 percent of Al, 0.015 to 0.025 percent of Ti, 1.15 to 1.35 percent of Cr, 0.001 to 0.005 percent of B, 0.0010 to 0.0050 percent of Ca, less than or equal to 0.015 percent of P, less than or equal to 0.003 percent of S, less than or equal to 0.0015 percent of O, less than or equal to 0.0030 percent of N, less than or equal to 0.00015 percent of H and the balance of Fe and inevitable impurity elements, and the carbon equivalent CEV is less than or equal to 0.54 percent. The production process comprises the following steps: electric furnace or converter steelmaking-gt; lF refining-gt; vD or RH high vacuum degassing-gt; continuous casting-gt; heating rolling-gt; carrying out online quenching-gt; and tempering. The steel plate structure is a fine tempered sorbite structure, and the grain size is smaller than or equal to 30 microns; the yield strength of the steel plate is larger than or equal to 960 MPa, the tensile strength of the steel plate is larger than or equal to 1000 MPa, and the ductility of the steel plate is larger than or equal to 10%; and transverse and longitudinal impact toughness Akv at-40 DEG C is greater than or equal to 30J.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, in particular to a low-crack sensitivity steel plate with a yield strength of 960 MPa and a manufacturing method thereof. Background technique [0002] High-strength steel plates with a yield strength of 960MPa are mainly used in key stress-bearing parts of construction machinery such as construction crane booms, crawler crane pull plates, and concrete pump trucks. Higher requirements. [0003] At present, there are two main production processes for high-strength steel plates with yield strength above 960MPa at home and abroad. The first is the off-line quenching and tempering process, that is, the steel plate is quenched and tempered off-line after hot rolling. For example, Chinese patent CN112126848A provides a high toughness quenched and tempered Q960 steel plate and a production method thereof. The C content of the steel plate is 0.16-0.18%, the Mn content is 1.30-1.40%, ...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide an ultra-high-strength steel plate with a yield strength of 960 MPa and its manufacturing method in view of the above-mentioned prior art. It adopts an alloy design with low carbon, low Mn and low carbon equivalent to solve the problem of quenching, cutting and welding of the steel plate. Cracking problem; through the online quenching process, solve the problems of long traditional quenching and tempering process, high energy consumption, and large amount of alloy addition; through optimizing the rolling process, solve the unevenness of the head and tail and transverse and longitudinal properties of the traditional controlled rolling + online quenching process steel plate The problem

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