Specific requirements for construction of stainless steel welded pipes for engineering | stainless steel pipe knowledge
The specific requirements for the construction of stainless steel welded pipes for engineering 2017-12-28 1. Welders must hold a certificate and are qualified to work after being approved by ABS. Their welding work should be consistent with the welder qualification approval items. During the welding construction process, the pipe assembly, the quality of tack welding and surface cleaning, whether the use of welding materials meets the specified requirements, and whether the performance indicators and instruments of the welding equipment are in good working condition must be carefully checked. 2. The stainless steel electrode must be baked as required, and then stored in an incubator at 120°C, and taken as needed. After the welding rod is taken out, it should be put into the incubator to avoid moisture. 3. When the welder is on duty, he should clarify the welding process requirements and check whether the welding consumables are consistent with the process requirements to avoid incorrect use. 4. The welder should check the shape of the cut and the cleanliness of the surrounding area before construction. 5. The gas filling device should be connected to the welded stainless steel pipe first, and the gas should be filled according to the 'argon filling method'. 6. Welding operation should be carried out under windproof and weatherproof conditions. 7. Before welding, adjust the shielding gas flow rate, and remove the air in the gas delivery pipe and the pipe to be welded for 1 to 2 minutes. The inlet for argon filling is arranged at the lower end of the pipe, and the pressure difference between the inlet and outlet is maintained at 0.02Mpa~0.05Mpa. 8. Before welding the stainless steel pipe, the two sides of the weld should be cleaned within 20~30mm as required. Because it is manual welding, chalk powder should be applied to the welding area to avoid the surface of the base metal from being damaged by splashed metal. 9. The welder should not start the arc at the non-weld seam, so as not to damage the base material and cause corrosion. 10. During manual arc welding operation, do not make lateral swing, narrow bead, fast, and control the interlayer temperature, the interlayer temperature of austenitic steel is less than 60℃. 11. All butt welds should be completely penetrated. Single-sided welding is adopted for double-sided forming. Whenever possible, the welding seam should be welded in the downward welding position. 12. Defects generated in welding. Such as cracks, end craters, pores and depressions should be removed in time. 13. When welding is interrupted, if the time is too long, the surface will be oxidized. When welding is continued, the end of the welding wire should be removed. When the arc is extinguished, the welding torch cannot be lifted immediately, and attention should be paid to the protective effect of the lagging gas on the weld. 14. After the weld is welded, it should be cooled for a period of time. When the temperature is less than 60°C (measured with a thermometer), the second layer of weld should be welded. 15. The welder should return the welding rod that has not been used up that day to the welding rod room. Before the next welding, the welding rod should be baked according to the regulations before use.