Stainless steel welded pipe production characteristics below phi 219mm stainless steel pipe is welded by the continuous roll forming and longitudinally welded pipe similar phi 219mm above the pressure forming (UOE or spiral weld (see spiral welded pipe) diameter 4.76mm following the drawing after welding production of capillary. Welding method has high frequency welding, tungsten inert gas arc welding (TIG or argon arc welding) laser welding, electron beam welding, etc.. High frequency welding can not guarantee the welding quality, but the welding speed is high, suitable for the production of general structure and decorative stainless steel welded pipe. And the vast majority of stainless steel welded pipe production using argon arc welding or argon arc welding and plasma welding combination. Decorative stainless steel welded pipe requires the appearance of grinding and polishing treatment. Chemical machinery, boiler heat exchanger with stainless steel welded pipe requires the formation of internal welding. Weld quality monitoring and non destructive testing system for welding seam structure through solid solution treatment. Argon arc welding of stainless steel welded pipe production process is as follows:
Plate roll slitting a strip a decoiling straightening flat all the butt welding of head and tail a loop forming argon arc welding to weld the outer gill (to welding thorn) a cooling size a eddy current flaw flying saw cutting
After cut off the stainless steel pipe according to the use of products and points the following 3 kinds of circumstances:
1 does not require heat treatment and drawing pipe by straightening a flat pressure check packaging storage elbow;
2. Need to heat treatment of welded pipe by defatting bright heat disposal a straightening straight a ultrasonic flaw detection in a flat head pressure for a check a packaging storage;
3 need to draw the welded pipe through the skim a forging tip one anneal one straightening a lubrication of a drawing all the first skim a bright anneal a finishing one check a packaging a warehousing;
A new technology of stainless steel welded pipe, using a plurality of electrodes (usually a three electrode) torch welding can also be is a combination of argon arc welding and plasma welding. Multi torch welding is fit for wall thickness greater than 2mm pipe, welding speed is 34 times higher than the single torch, the welding quality can also be improved. In addition, argon adding 5% ~ 10% hydrogen, using high frequency pulse welding power, welding speed is increased; in order to ensure the welding quality by the torch on the weld automatic tracking device, the arc voltage automatic control system (AVC computer control of welding process. Clear welding thorn method: 1 wall gas supporting technology, wall filled with certain pressure of inert gas to boosting the molten liquid drops, do not make the sagging, so as not to form a bonding thorn; the inner wall of the hammer technology for diameter 30mm pipe; 3. The inner wall of the rolling technology for more than 50mm in the welded tube; decorative tube to be equipped with a high efficiency of grinding and polishing equipment to improve stainless welded pipe appearance bright and clean level.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)