With the acceleration of global industrialization and informatization, the increasing demand for energy has accelerated the pace of construction of long-distance pipelines in China, and forced the pipelines for long-distance pipelines to move toward high-grade steel, large-diameter and thick-walled. Driven by this trend, traditional electrode arc welding is gradually being replaced by semi-automatic welding and automatic welding methods. The welding method has also gradually evolved from traditional up-welding to all-position down-welding, which is promoted and driven by it. The continuous innovation and development of materials for long-distance pipeline welding construction.
I. Development status of welding materials for down welding of long distance pipelines at home and abroad
At present, with the continuous change of welding methods and long-distance pipelines (material, wall thickness and pipe diameter), the demand for welding materials for long-distance pipelines is: reasonable strength and toughness, high deposition rate And welding speed, better all-position down-welding ability and better field welding operation performance, lower spatter rate and harmful smoke rate and higher requirements in environmental protection, etc. The research and development put forward higher requirements.
China's welding materials for the downward welding of long-distance pipelines have only been developed by children's manufacturers in recent years. At present, only the Sichuan Atlantic CHE425GX ψ3.2/ψ4 is mature in the high-fiber type welding electrodes for down-welding. 0mm welding rod, and SRE425Gψ3.2/ψ4.0mm welding rod developed by CSIC 725, SRE505Gψ4.0mm welding rod, SRE555Gψ4.0mm welding rod. In terms of iron powder low-hydrogen welding rods, there are no mature products listed in China. The flux cored wire is only Tianjin Jinqiao JC-29Nilψ2.0mm and JC-30Ni2ψ2.0mm self-shielded flux cored wire. For the solid welding wire, only Jinzhou Jintai JM-58 (ER70S-G) ψ1.2mm, JM-68 (ER80S-G) ψ0.9/ψ1.0mm welding wire is currently used in long-distance pipeline welding construction.
Foreign countries have developed and applied the welding materials for pipeline down welding earlier, and the product performance is basically stable. At present, the well-known welding consumables companies include American Lincoln/Haubbert welding consumables, Austria Bole welding consumables, Swedish ESAB welding consumables, and Italian RMS. /SAF welding consumables, South Korea Pohang welding consumables and Japan Kobelco welding consumables. Welding consumables include high cellulose type electrodes (E6010, E8010, E9010), iron powder low hydrogen type electrodes (E8018, E9018, E10018), self-protecting/gas-shielded flux-cored welding wire (E71T8, E81T8), and gas protection Core wire (ER70S, ER80S, ER90S, ER100S), etc. Among them, Bole/Lincoln cellulose type and low hydrogen type welding materials, Lincoln/Habert's self-shielded flux cored wire and Bole gas shielded solid wire are prominent.
In general, there are too few and incomplete welding consumables for domestic pipelines. There are still no samples of iron powder low-hydrogen welding consumables. Gas-shielded solid welding wire is only used for low-grade steel pipe welding and high-cellulose welding. Materials and self-shielded flux-cored wire are still in the improvement stage, and their scale, branding and market recognition still take a long time. Foreign large welding consumables manufacturers have their own well-known brands for pipeline welding construction, and currently have their own main products monopolized part of the market. In fact, China's key long-distance pipeline projects that have been built and are under construction in recent years are almost all foreign brand welding consumables. The corresponding domestic welding consumables are unstable due to the performance of mass production and performance. Pipeline construction owners still use less.
