Ultrahigh-strength welding structure steel plate and its manufacturing method

Abstract

The invention discloses an ultrahigh-strength welding structure steel plate. The steel plate comprises 0.11-0.19% of C, 0.20-0.50% of Si, 0.90-1.40% of Mn, 0.005-0.030% of Ti, 0.30-1.00% of Cr, 0.1-0.5% of Cu, 0.15-0.35% of Ni, 0.15-0.60% of Mo, 0.010-0.050% of Als, 0.020% or less of P, 0.010% or less of S, 0.025-0.070% of V, 0.005% or less of Zr, and the balance Fe and inevitable impurities. Quenching and tempering treatments of the steel plate are carried out after rolling, the reheating temperature is 860-930DEG C, the temperature insulation is carried out for 1.0-2.5min / mm, and water quenching is carried out to obtain a quenching martensite structure; and a tempering treatment is carried out at 500-600DEG C, the heat insulation time is 1.0-3.0min / mm, and air cooling is carried out.

Description

technical field [0001] The invention belongs to the field of metal materials, and in particular relates to a steel plate for an ultra-high-strength welded structure with a yield strength of more than 900 MPa and a manufacturing method thereof. Background technique [0002] At present, the development trend in the field of machinery manufacturing such as truck cranes, heavy-duty trucks, concrete pump trucks, semi-trailers, and containers is to develop in the direction of high parameters and large-scale, so more and more ultra-high-strength welded structural steels are used. It is to reduce the weight, improve the carrying capacity and save energy. At the same time, ultra-high-strength steel plates are required to have the characteristics of low cost, good welding performance, and high low-temperature toughness. [0003] Ultra-high-strength steel plates are manufactured by quenching + tempering (Q+T), direct quenching + tempering (DQ+T) after rolling, controlled rolling and c...

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Problems solved by technology

[0004] From the comparison of the above patents, we can see that the current patents for ultra-high-strength steel plates with a yield strength of about 900-1050 MPa have the main disadvantages: the steel contains B elements, and the low-temperature toughness is poor; the precious element Ni content in the steel plate is high, and the cost of the steel type is high.

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