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Welding technology of natural gas pipeline welding
Date:2020-08-27      Views:241Time      Label:Welding technology of natural gas pipeline welding

(1) Material requirements: materials and specifications must comply with the design requirements, with a factory certificate and retest report.

(2) Welding rod requirements: the coating has no defects such as cracks. Pores, etc. The arc should burn stably, melt uniformly, and have no lumps and fall off during welding. The user needs to be dried.

(3) Preparation before welding: the inner wall of the nozzle should be cleaned and flush, the amount of misalignment should not be more than 1mm, the welding device is solid, and necessary measures should be taken to prevent welding stress and deformation.

(4) Welding equipment: AC welding machine, a DC welding machine, angle grinder, drying box, heat preservation barrel.

(5) Welder requirements: Welders must hold a welding certificate and be trained and assessed before commencing their job. The work site has safety protection to prevent burns, electric shock, and collapses.

(6) Welding process: Derust the pipeline before welding, and brush anti-rust paint after exposing the metal color. Use reasonable welding method and sequence when welding pipes to ensure the quality of arc beginning and ending points. Multi-layer welding joints should be staggered, and slag and spatter should be removed after each layer is welded. If there gets some defect, use an angle grinder to remove and re-weld. Single-sided manual arc welding is used for welding, and each layer is polished with a handwheel before welding the succeeding layer. To reduce welding deformation and welding stress, symmetrical or segmented welding methods can be utilized. All welds should be visually inspected. The height of weld reinforcement is 1mm, and the width of the weld should cover the groove by 2mm. No cracks on the weld surface: seams, pores, slag inclusion. The weld seam should reach 100% qualification of Class II.