Non-preheating welding method of 750MPa-grade high-strength steel medium-thickness plate for hydraulic support

Abstract

The invention provides a non-preheating welding method of a 750MPa-grade high-strength steel medium-thickness plate for a hydraulic support. The non-preheating welding method comprises the following steps: assembling parts into a hydraulic support structural part assembly; carrying out manual tack welding on all welding seams of the assembled hydraulic support structural part assembly; carrying out manual overall backing welding on the hydraulic support structural part assembly subjected to manual tack welding; carrying out overall backing welding on the hydraulic support structural part assembly subjected to manual overall backing welding through a welding robot; and carrying out filling welding and cosmetic welding on the hydraulic support structural part assembly subjected to overall backing welding through the welding robot one welding bead after the other through the welding robot. The non-preheating welding method of the 750MPa-grade high-strength steel medium-thickness plate for the pressing support has the advantages that the design is scientific, the preheating step is not needed, the welding quality can be guaranteed, and application and popularization are easy.

Description

technical field [0001] The invention relates to a welding method for a structural part for a hydraulic support, in particular to a non-preheating welding method for a 750MPa grade high-strength steel plate for a hydraulic support. Background technique [0002] As the main support equipment in fully mechanized mining equipment in coal mines, hydraulic supports have high requirements for pressure resistance and corrosion resistance due to the harsh underground service conditions. The structural parts of the hydraulic support are mainly composed of medium-thick plates of low-alloy high-strength steel. The thickness of the medium-thick plates is generally 20-50mm. These structural parts generally adopt a box-shaped structure, which has low assembly accuracy, large welding volume, and high material strength. , poor weldability, and high welding restraint. [0003] The strength grades of steel used for traditional hydraulic support structural parts are: Q355, Q460, Q550, Q690 and...

AI Technical Summary

Problems solved by technology

In recent years, although some Q690 steel plate welding methods without preheating have been developed in the industry, they are generally applied to medium and thin steel plates with a thickness of less than 30mm. However, the thicker the plate, the worse the welding restraint. The preheating welding method is applied to thick plates with a thickness of 35-50mm, which is very prone to defects such as cold cracks, hot cracks, and lack of fusion, which makes it impossible to be practically applied. Due to the disadvantages of high cost, unstable performance, and poor welding stability, etc., The above-mentioned non-preheating welding method has not been promoted in the industry

[0004] The medium-thick steel plate with a tensile strength of 750MPa is similar to Q690 in composition, and its weldability is poor when it is applied to a multi-box structure with concentrated weld seams and large restraint stress in hydraulic supports, and it is difficult to weld without preheating. In the industry, the research on the welding process of the medium and thick plates of this steel plate is even blank

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