1.单面焊双面成形技术的概念（1. Concept of single-side welding double-sided forming technology）.docVIP

1.单面焊双面成形技术的概念（1. Concept of single-side welding double-sided forming technology） The concept of single side welding double - side forming technology One-side welding of forming technology is to use ordinary electrode, under the condition of without any auxiliary measures, is located in assembling welding groove root, should according to the different operation methods to set aside in the welding gap, in the front of the groove welding, and are in breach of the back on both sides can get uniform neat, forming good, meet the requirements of the quality of weld. This method is mainly suitable for plate butt joint, tubular butt joint and saddle pipe joint. Is the boiler, pressure vessel welder should be skilled in the operation skills [1]. 2. Welding defects of single side welding are common 2.1 defects in size The size error of welding structure and poor weld shape are included. Rugged and corrugated poor weld appearance, uneven weld width, too wide or too narrow, the weld residual high too low or too high, the fillet weld leg size ranging from belong to the weld dimension and shape is not in conformity with the requirements. These defects not only make the weld forming not beautiful, but also easily cause the stress concentration, affect the bonding strength of the weld and the mother material. 2.2 structural defects Including stomata, slag, non-metallic inclusions, fusion bad, unsoldered, edge, crack, surface defects etc. These defects are the most obvious defects in the welding process. The defects of the weld effective area, reduces the mechanical properties of welded joint, and easy to cause stress concentration, cause cracks, cause structural failure, make welding structure cannot work under normal load. 2.3 defects in nature The defects including mechanical properties and chemical properties of the welding parts are not met. Mechanical properties refer to tensile strength, yield point, elongation, hardness, impact absorption work, plasticity, fatigue strength,