Summarized the current pipeline construction welded pipe process are the following categories:
A cellulose electrode manual welding to the next, more serious when the hydrogen sulfide corrosion of the pipeline or in cold environments pipeline, set to the low hydrogen type electrode welding.
Because the flexibility of manual welding and welding equipment ask for much other reasons, the current outdoor pipe welding, manual metal arc welding of work still accounts for 40-50%, such as China's Shaanxi Province to Beijing in recent years, the pipeline project purchased from Bio-Rad a variety of cellulose electrodes 1,000 tons, the pre- Measured the next few years China's oil and gas pipelines in the amount of bits required to electrodes 3-5 tons, and there is an increasing trend.
2 set to cellulose backing welding electrodes, CO2 gas shielded welding fill surface.
Because CO2 welding, high productivity, low cost, the method in recent years has been the promotion and application, but oil and gas pipeline welding, to achieve the all-position welding must be in a smaller current range, with short transitional form to complete, and with short circuit transfer mode prone to bottoming welding defects such as lack of penetration , So a primer set to achieve single-sided welding cellulosic electrodes, forming the back, and then use the high efficiency of the CO2 gas welding fill surface, the more common applications of this technology.
3 self-shielded flux cored wire semi-automatic welding
Self-shielded flux cored wire semi-automatic welding particularly suitable for outdoor windy situations, it does not use the CO2 produced by the cored gas, wind, and can be used to pipe high deposition rate of all-position welding, currently Lincoln self-shielded flux cored wire production to countries recognized by its brand Are: NR-207, NR-204-H, NR-208-H and other, applicable to X70, X80 and other pipeline set to welding. But there are also backing the method of soldering is not prone to fusion weld root defects.
4 high-performance CO2 gas shielded welding of semi or fully automatic welding.
CO2 gas welding due to short-circuit transition process control technology in-depth research results, have now produced abroad, the welding current and voltage waveforms for timely control or power control of the output characteristics of high-performance power supply, above the surface of the U.S. Lincoln's STT Tension Transfer
Welding
Access technology on the part of the waveform control areas. Based on the improvement of welding equipment performance, making the pipeline to achieve semi-automatic and fully automatic CO2 gas welding can be properly achieved, which greatly increased welding efficiency and welding quality. In addition, the plant is also used within the automatic pipe welding TIG welding .The method of good quality, but low productivity.
