Carbon steel pipe welding technology

Abstract

The invention discloses a carbon steel pipe welding technology. The welding technology includes the following steps that groove machining is conducted, the pipe groove form and groove size of a pipe should meet the stipulation of a design document or a welding technology card; grouping is conducted, paint, dirt, burrs and zinc coatings arranged at the position, within the range of being larger than or equal to 10 mm, of a groove and the surfaces of the inner side and the outer side of the groove should be cleaned completely before welding piece grouping is conducted, when the inner-wall alignment tolerance of the pipe or a pipe fitting is 10% smaller than the pipe wall thickness when the pipe or the pipe fitting is in butt joint with a connector; first-time preheating is conducted on welding piece pairs before welding, and the preheating temperature ranges from 100 DEG C to 200 DEG C; positioning welding is conducted on welding assemblies generated after first-time preheating is conducted, the welded assemblies with defects are removed immediately, second-time preheating is conducted after reposition is conducted, and the welding is conducted again. By means of the principle, the alignment tolerance of the inner wall is accurately mastered, the groove is processed accurately, the processing process is optimized, and the mechanical strength of the welding seam position is improved.

Description

technical field [0001] The invention relates to the field of steel pipe welding, in particular to a welding process for carbon steel pipes. Background technique [0002] At present, with the development of science and technology, all walks of life are increasing the number of conveying pipeline products in the machinery industry. For example, in the oil exploration industry, a large number of large-diameter and high-performance conveying pipes are required. In low and medium pressure boilers Steel pipes, carbon steel pipes are also used in high pressure boiler steel pipes. The welding quality requirements of carbon steel pipes are relatively high, and the existing steel pipe welding process has poor welding mechanical properties at the welds of carbon steel pipes, which can no longer meet the applications in some fields that require high mechanical properties at the welds. Today, some steel pipe manufacturers use submerged arc welding to weld carbon steel pipes and stainles...

AI Technical Summary

Problems solved by technology

The welding quality requirements of carbon steel pipes are relatively high, and the existing steel pipe welding process has poor welding mechanical properties at the weld seam of carbon steel pipes, which can no longer meet the applications in some fields that require high mechanical properties at the weld seam.

Today, some steel pipe manufacturers use submerged arc welding to weld carbon steel pipes and stainless steel pipes in order to solve this problem. However, this method uses a single steel plate production method, resulting in a production volume that is far from meeting the market demand.

In addition, in today's steel pipe welding process, the improper grasp of the amount of misalignment of the inner wall and the inadequate treatment of the groove further aggravate the weak strength of the welding mechanical properties of the carbon steel pipe weld.

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