Non-preheating welding Q690D steel plate for coal mine machinery and preparation method of non-preheating welding Q690D steel plate

Abstract

The invention discloses a non-preheating welding Q690D steel plate for coal mine machinery, and relates to the technical field of steel smelting. The non-preheating welding Q690D steel plate for coalmine machinery comprises the following chemical components of, in percentage by mass, 0.05% to 0.06% of C, 0.20% to 0.25% of Si, 1.7% to 1.8% of Mn, less than or equal to 0.010% of P, less than or equal to 0.005% of S, 0.4% to 0.5% of Cr, 0.008% to 0.012% of B, 0.01% to 0.03% of Ti, 0.01% to 0.03% of Zr and the balance Fe and inevitable impurities. According to the non-preheating welding Q690D steel plate for coal mine machinery, on the basis that Nb and Mo elements with high cost are not added, an online quenching process is adopted, and on the basis that the alloy cost is reduced and the process route is simplified, the steel plate finally meets the requirement for the preheating-free welding performance at the temperature of 0 to 20 DEG C through simple rolling and online quenching processes.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a Q690D steel plate for non-preheating welded coal mine machinery and a preparation method thereof. Background technique [0002] With the technological progress of the coal mining machinery industry, the demand for the strength grade of steel plates for related mechanical equipment is getting higher and higher, and at the same time, strict requirements are put forward for its performance. In order to prevent the cold crack tendency of Q690D steel plate used for high-strength coal mining machinery under the existing conditions of use, the corresponding welding process needs to be preheated before welding at a temperature above 100°C, which leads to a more time-consuming actual production process and directly reduces production. efficiency. At the same time, it is difficult to use high-efficiency robot welding during the pre-welding preheating process, which limit...

AI Technical Summary

Problems solved by technology

In order to prevent the cold crack tendency of Q690D steel plate used for high-strength coal mining machinery under the existing conditions of use, the corresponding welding process needs to be preheated before welding at a temperature above 100°C, which leads to a more time-consuming actual production process and directly reduces production. efficiency

At the same time, it is difficult to use high-efficiency robot welding when performing the pre-welding preheating process, which limits the effective implementation of efficient and intelligent manufacturing processes in the coal mining machinery industry

[0003] Chinese patent document CN104018085A discloses a thick gauge Q690D high-strength and high-toughness steel plate and its production method. In the composition design, Nb, V, Ti, Cr and Mo are added, and the quenching and tempering process is adopted. The product meets the mechanical properties requirements, but does not mention whether it meets the requirements of room temperature no preheating welding process

[0004] Chinese patent document CN107058898A discloses a Q690D low-carbon bainite steel and its production method. Nb, Ti, Cr and Mo are added to the composition design, and a two-stage rolling process is adopted. The product meets the basic mechanical performance requirements , the same, it does not mention whether it meets the requirements of room temperature no preheating welding process

This patent involves the specific production method of high-strength steel without preheating, which can meet the requirements of basic mechanical properties and welding process requirements without preheating at room temperature. Fire technology, the product manufacturing cost is high, and the minimum welding temperature without preheating is 5°C. In order to meet the temperature requirements of the coal mining machinery industry in winter use, the lower limit temperature is still insufficient

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