The Research On The Pipeline All-position Self-protective Fuse-wire

In the light of the actual situation that advanced welding technology, i.e.semi-automatic welding with top-notch, efficient solder wire has been widely usedon pipeline welding construction in foreign industrial countries, and in order to catchup with the advanced technology on foreign pipeline welding construction and tomake China Petroleum Pipeline Bureau (CPPB) more competitive on pipelinewelding construction in international market, CPPB introduced a set of fuse-wireproduction line to go on the research and development of fuse-wire. However, therehave been some problems with the quality of the product such as dripping slag,heavy splash, unstable low-temperature impact values in welding. Therefore, ascience research program has been set up for more reliable and stable wire. In view of the defects of the imported product of the self-protective fuse-wire onall-position pipeline welding by the Russian formula, a great deal of adjustment andresearch have been done and the formula has been optimized with a view to solvingthe problem of the impact on the wire under low temperature. Various fluorides work as both gas-making agent and slag-making agent in thefuse. As a result, the protective property of gas by different fluorides has been widelyresearched in recent years. It is assumed that fluorides such as BaF2 , CeF2 , LiF, K2ZrF6 , Na2 SiF6 and the like have a low boiling point and could be easily gasified,thus have a positive effect on the improvement of the protective property of gas andhelp improve the toughness of welding seam, but excessive amount may result inunstable electrical arc and more splash. The original formula with K2 ZrF6 and Na2SiF6 added in and adjusted amount of fluorides could produce less Al-Mg alloy andreduce the aluminum content. It is confirmed that rare earth could purify welding seam, denature slag inclusionand result in slight alloying which are favorable to improve the low-temperaturetoughness and high-temperature strength as well as the corrosion resistance ofwelding seam, but so far it could not be quantified. The experimental formula hasbeen supplemented with rare-earth fluorides of different amount respectively on thebasis of the original one to conduct fusing metal welding experiment. In view of theimported linear pulling Russian fuse-wire production line, production technology hasbeen reasonably adjusted to determine the production quality guarantee system aswell as quality control system and to meet the demand of industrialized production. Stable, reliable and qualified solder wires which can meet the need of pipelineconstruction could be finally manufactured through above-mentioned research toreplace the imported wire to perform all-position pipeline welding with domesticself-protective wire.