Marine reference pipe generally involves the ship crew drinking water security, and so on welding quality in the process of piping fabrication and installation quality is especially important To ensure the welding quality of pipeline and pipeline internal cleanliness, usually adopts argon arc welding backing or pure argon welding with argon arc welding of stainless steel, due to the affinity of oxygen and stainless steel is very big, if not weld protection measures, on the back of the weld metal is easy to oxidation in the process of welding, alloy elements burning loss, and easy to produce welding defects, caused by weld metal mechanical properties and corrosion resistance

When the argon arc welding of stainless steel pipe, to ensure the quality of welding seam on the back of the welding, effective protection measures must be taken Stainless steel pipe production process, generally USES the method of argon arc welding of tube, can prevent the oxidation of the welding seam on the back, make the weld mechanical properties and corrosion resistance of get effective guarantee Now the argon arc welding of stainless steel in argon protection and introduces the matters needing attention on the back

Blunt argon protection: a tube tube rushed argon method is to prevent the oxidation of the welding seam on the back of the argon methods mainly include the overall impact and argon and partial argon

1 whole blunt argon: for small diameter pipe or fitting group of pipe is relatively short, can be used as a whole argon and the method is simple Overall argon filling method is: will be sealed with adhesive tape (paper plate, etc.) on both ends, from one end of the tube filled with argon gas, the other end of the upper sealing on emissions of a 3 ~ 5 mm hole, mainly to prevent crater arc argon pressure when the tube is too big, cause arc difficult, produce the defects such as pits In addition to prevent the docking port clearance in argon discharge, paper and duct tape in advance can end nozzle, only leave a welder welding a continuous length, until the welding is complete

The argon gas protection effect judgment

Argon gas protection effect can be determine according to weld the color during the welding process, welding, shielding gas can be adjusted according to the color, to weld are good protection effect The color with silver, gold for the best Blue is good Red gray is better Gray bad black is the worst

The blunt argon protecting matters needing attention

argon arc welding seam on the back should be ahead of plenum, traffic, appropriate air after discharge, discharge are fully protected Another should pay special attention to the air after the net can be welded, affect the effect of charging - otherwise

Argon gas flow should be appropriate flow 2 is too small, protection is not good, the back weld easy oxidation; Vortex flow is too large, when welding the lead into the air, protect the effect will be worse, at the same time will cause defects such as weld root concave, affect the welding quality

the location of the argon gas entrance should be placed in the closed period of as low as possible, air outlet should be placed in the closed period of high Because air, argon gas wall from the low position filled with argon gas, easy to be protected for higher concentration argon protection effect is better

in order to reduce the loss of tube from the end clearance of argon protection effect, increase the cost, can be along the joint gap paste paper tape before welding, just leave a welder to the length of the arc welding

In the actual welding process, according to the actual situation of the scene, the welder welding, and welding materials and the level of parent metal, adjust the welding process parameters, measures for the protection of welding seam on the back of the flexible choice, in order to achieve the best welding quality