Welding and Operating Procedures for Stainless Steel Gas Pipelines
Release time:2024-02-26
1、 Construction process flow
1. Construction preparation
2. Material entry inspection
3. Material cutting and installation
4. Valve inspection
5. Pipeline welding
6. Gas flushing
7. System pressure test
2、 Welding process of stainless steel pipe
·Welding base material: stainless steel pipe, wall thickness 2-3mm.
·Welding material: stainless steel welding wire, diameter 2.0-3.0mm.
·Welding method: automatic argon arc welding, with argon gas protection throughout the pipeline.
·Tungsten electrode specification: diameter 2.0mm.
·Welding machine parameters: current 60-160A, argon flow rate 9-20ml/s.
·Argon flow rate inside the tube: Adjust according to the welder's operating technique.
Quality standards:
·The appearance of the weld seam is level with the parent body, resembling a fish scale.
·No defects such as oxidation, pores, cracks, bumps, poor fusion, or misalignment.
·The width of the weld seam is about twice the thickness of the base metal.
·Single sided welding achieves double-sided forming.
·The inner wall is smooth and level with the inner wall of the mother body.
Welding inspection and quality control:
1. Weld appearance inspection to ensure no defects.
2. The edge of the weld seam smoothly transitions with the base metal, resulting in an aesthetically pleasing shape.
3. It is strictly prohibited to strike an arc or test the current on the welded parts.
4. When welding multiple layers, the joints should be staggered and the arc should be stopped to fill the arc pit.
5. Argon arc welding is guaranteed to be completed in one go.
6. Remove the weld seam and spatter after welding.
3、 Operation process
1. The end face should be polished flat, vertical, and free of perspective lines.
2. Secure spot welding at multiple points and add blockages to form cavities.
3. Adjust the inflation and welding machine pressure to ensure the flow state.
4. After clearing the air inside the pipe, start welding.
5. Fill the pipeline with argon gas and weld it after the purity meets the standard, with a flow rate of 0.3-0.5 liters per minute.
4、 Welding Operation Overview
The argon arc welding nozzle swings smoothly and runs almost tangential along the circumferential weld seam, with the tungsten electrode tip within 5mm of the pipe surface.
5、 Post weld treatment
1. Gas flushing: Clean with a polishing pad after welding, and passivate or polish the surface.
2. Pipeline pressure test: After installation, conduct a pressure test. The pressure gradually increases to 1.2 times the normal operating pressure, and if there is no leakage or deformation after stabilizing for 30 minutes, it is considered qualified. Reduce to work pressure, stabilize for 2 hours, and if the pressure stabilizes, the tightness test is qualified.