Manufacturing method of aluminum-free low-alloy steel plate suitable for high heat input welding

Abstract

The invention relates to a smelting method of aluminum-free low-alloy steel suitable for high heat input welding. Through converter, LF refining and RH treatment, molten steel is obtained, and comprises the following components in percentage by weight of less than or equal to 15PPm of free [O], less than or equal to 0.008% of P, less than or equal to 0.30% of Cu, less than or equal to 0.30% of Ni, less than or equal to 0.06% of Mo, more than or equal to 4 * [N]-0.06% of V, less than or equal to 0.003% of S, less than or equal to 0.0008% of B, less than or equal to 0.30% of Cr, less than or equal to 0.007% of Alt, 0.03-0.07% of C, 1.30-1.60% of Mn, 0.15-0.30% of Si, 0.011-0.022% of Ti, 35-60ppm of [N], 0.015-0.025% of Nb and the balance Fe and inescapable impurities in steel. A casting blank produced by taking the molten steel as a raw material can be used for rolling the thick steel plate for high heat input welding by using a TMCP process, the process is simple, the production continuity is good, the component control is accurate, and the high heat input welding performance of a finished product is reliable.

Description

technical field [0001] The invention relates to a method for smelting low-alloy steel which does not contain aluminum and is suitable for high-energy welding, and belongs to the field of low-alloy steel manufacturing. Background technique [0002] Welding is the most important connection method for steel structures. During the welding process of the steel plate, due to the action of the welding heat cycle, the microstructure and properties of the welding heat-affected zone will change, especially the low-temperature toughness will be greatly reduced. In order to ensure the quality of welded joints of steel structures, traditional structural steels generally need to strictly limit the welding line energy, implement weld bead layout, control interlayer temperature, and sometimes preheat before welding. Although the reliability of welded structural parts can be effectively guaranteed through strict standardized operations, it also greatly limits the efficiency of welding opera...

AI Technical Summary

Problems solved by technology

The problem is how to prevent various easily oxidizable elements from forming oxides in the liquid phase, polymerizing and floating, and at the same time, the formed oxides can exist in the steel in a finely dispersed state.

[0021] Although these manufacturing methods can obtain steel plates suitable for large heat input welding, the preparation methods of the above-mentioned prior art are difficult to stably obtain the so-called Ti-Ca-Mn-O-S and also contain RE oxides, which is conducive to the effective use of large heat energy welding. inclusions

And the welding performance of the prepared steel plate fluctuates too much, the performance is unstable, and the performance is unreliable

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