Introduction to the key points of welding Hastelloy pipe
1. Hastelloy Pipe Welding Steps
Ⅰ. The white tape attached to the bottom and both sides of the groove during welding should be reversed; Otherwise, it should be cleaned with acetone before soldering.
2. Use less wire power when welding. The front end of the welding wire (heated end) must be in gas shielding state. The entire welding process must use short arc welding to control the temperature between passes. When the arc closes, the arc crater will be filled and the gas will be delayed for 30 seconds to stop and prevent the appearance of hot cracks.
three. The tungsten electrode should avoid contact with the molten pool and welding wire, shorten the arc length as much as possible, and prevent the weld from being filled with tungsten.
Four. Make sure the welding speed is appropriate. The speed is slow and the weld metal wire energy is high, resulting in greater combustion loss of weld metal alloy elements. The structure of the weld heat-affected zone is overheated, which increases the grain size. The physical properties of the welded joint decrease at high speed and the protection of the molten pool is poor. The metallurgical reaction is poor, the welding temperature is low, the welding edge is poorly fused, and crater-shaped cracks are likely to occur.
2. Welding construction managers should wear special gloves and fixed accessories for pairs. Carefully fill the arch crater when filling the arch to avoid cracks in the crater. A windshield must be placed in the welding position. The difference in width of the welding seam between the Windshield pairs and the windshield should be 1 to 2 mm. The highest requirements are 0 ~ 1.6mm, the weld surface must not have cracks, unfused undercuts, pores, slag inclusions and other surface defects, the weld must be visible on the X-flaw detector by lightning, fillet weld penetration, etc.
3. Weld quality conditions: All welds made on site have been inspected by radiographic flaw detection, and the first pass rate and weld surface quality inspection have met the qualification requirements.
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