Classification of European standards are smaller, highly targeted features in the applications pay attention to the preconditions, such as using manual arc welding electrode during welding structural steel standards EN499, EN757, EN499 Material yield strength for the strength of the structure ≤ 500Mpa steel, and EN757 for material yield strength> 500Mpa the strength of structural steel. In addition, while in the development of European standards, academic institutions or authorities by established norms or the use of many materials, procedures, materials developed for cold or hot processing technology regulations are based, such as Germany's iron and steel material specification SEW088 (melting of materials Welding of manufacturing procedures.) If it were not special orders, then the time of manufacture of the material in the weld can be SEW088 to develop welding.
Next to the welding technology development and progress depends on the welding electrodes ,clamp, wire feeder, running gear and other equipment of the technological maturity and the stability of welding process performance. Pipeline projects under a variety of welding technology mainly to two factors. 4.1 Project environmental conditions
Poor environment in some areas, limiting the application of advanced welding technology. For example, some water network areas, due to air humidity, drying of welding consumables, storage, use of demanding multi-site welding arc welding with welding rods, because the fiber electrode with low hydrogen type electrode than in the pores under the same conditions produced tendency to small. On the other hand, the construction site water network zone, automatic, semi-automatic welding equipment use more difficult, and manual welding the welding clamp is small, flexible operations, the mechanical properties to meet the premise of the weld can be selected based on practical welding field conditions methods. 4.2 The technical condition of tooling equipment Advanced automatic, semi-automatic welding equipment will greatly improve the welding efficiency, despite the huge investments required to renew their equipment, but in the long-distance pipeline construction peak time, the market rate of return is substantial. Only have the technology, only with the market.