High heat input welding high-intensity hot-rolled steel bar and production technology thereof

Abstract

The invention discloses a high heat input welded high-intensity hot-rolled steel bar which comprises 0.27-0.29 percent of C, 0.15-0.17 percent of Si, 1.11-1.13 percent of Mn, 0.007-0.009 percent of P, 0.001-0.003 percent of S, 0.057-0.059 percent of Als, 0.005-0.007 percent of Nb, 0.06-0.08 percent of V, 0.035-0.037 percent of Ti, 0.05-0.07 percent of Ni, 0.07-0.09 percent of Cu, 0.6-0.8 percent of Cr, 0.53-0.55 percent of Mo, 0.007-0.009 percent of B, 0.07-0.09 percent of lanthanum, 0.03-0.05 percent of cerium, 0.01-0.03 percent of praseodymium and the balance of Fe. According to the high heat input welded high-intensity hot-rolled steel bar, the intensity of the steel bar and the toughness of a welding heat affecting region can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of high-strength steel bars for welding, in particular to a high-strength hot-rolled steel bar welded with large input energy and a production process thereof. Background technique [0002] In the past, the welding line energy of steel in welding construction ≥ 50 kJ / cm can be called high-line energy welding, but current data show that the actual welding line energy of gas-electric vertical welding large-line energy welding has even exceeded 500 kJ / cm . Under such a large welding input energy, the heat-affected zone (HAZ) structure of traditional low-alloy high-strength steel (HSLA) will grow rapidly, the strength and toughness of the welded part will be greatly reduced, and welding cold cracks will easily occur question. In addition, for the traditional thermomechanical rolling (TMCP) technology, with the increase of the strength and thickness of the steel bar, the carbon equivalent must be increased to e...

AI Technical Summary

Problems solved by technology

Under such a large welding input energy, the heat-affected zone (HAZ) structure of traditional low-alloy high-strength steel (HSLA) will grow rapidly, the strength and toughness of the welded part will be greatly reduced, and welding cold cracks will easily occur question

In addition, for the traditional thermomechanical rolling (TMCP) technology, with the increase of the strength and thickness of the steel bar, the carbon equivalent must be increased to ensure the conventional performance, but the increase of the carbon equivalent will deteriorate the welding performance of the steel plate

Existing high-strength steel bars do not have the performance of high-energy-input welding resistance. When welding, high-energy-input welding methods exceeding 50kJ / cm cannot be used for welding. The construction efficiency is low, and the requirements for high-energy-input welding cannot be met, and the welding efficiency is low.