Steel bar for high heat input welding high-speed rail engineering and production technology of steel bar

Abstract

The invention discloses a steel bar for high heat input welding high-speed rail engineering. The steel bar comprises the following components: 0.21-0.23 percent of C, 0.11-0.13 percent of Si, 1.81-1.83 percent of Mn, 0.003-0.005 percent of P, 0.004-0.006 percent of S, 0.037-0.039 percent of Als, 0.007-0.009 percent of Nb, 0.06-0.08 percent of V, 0.045-0.047 percent of Ti, 0.02-0.04 percent of Ni, 0.03-0.05 percent of Cu, 0.1-0.3 percent of Cr, 0.33-0.35 percent of Mo and the balance of Fe and unavoidable impurities. The steel bar for the high heat input welding high-speed rail engineering is provided with a large quantity of fine dispersed inclusions; the quantity of composite inclusions containing Ti oxide and nitride is several times greater than that of the composite inclusions in a conventional 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, and in particular relates to a steel bar for large-energy-input welding high-speed rail engineering 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...

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.