spiral welded steel pipe wv Semi-automatic FCAW downward welding is operated under different process parameters, and there are three droplet transition phenomena.Namely short circuit transition, large particle transition, fine particle transition.
spiral welded steel pipe wv
High quality assured sprial welded steel fluid transport price list available pipe for sale
Thickness: Length 6-30m
ASTM A500, BS1387,GB3091,ASTMA53, B36.10, BS EN1029, GB/T9711 etc
API 5L, ASTM A53 GrA,GrB; STKM11,ST37,ST52, 16Mn,etc.
Plain ends, cutting, etc
1. PVC,black and color painting
2. Transparent oil,anti-rust oil
3. According to clients requirement
Bundle;Bulk;Plastic bags ,etc
We can do special orders as customer's requirement.
We also can provide all kinds of steel hollow pipes.
All the production process are made under the ISO9001:2008 strictly
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|Chemical Composition%||Mechanical Property|
|C%||Mn%||S%||P%||Si%||Yield Point (Mpa)||Tensile Strength(Mpa)||Elongation |
What Semi-automatic FCAW is？
Semi-automatic FCAW downward welding is operated under different process parameters, and there are three droplet transition phenomena.Namely short circuit transition, large particle transition, fine particle transition.Comprehensive process parameters are commonly used in all - position downward welding process of pipeline.This parameter is suitable for vertical welding. The horizontal welding is relatively low and the overhead welding is relatively high.In small parameters, such as low arc voltage, low thrust current, wire feeding speed and other mismatched parameters, for short circuit transition.As the voltage is low and the arc length is shortened, the droplet will come into contact with the metal in the molten pool before the neck is shrunk. Under the action of surface tension and gravity, the transition, explosion and re-arcing will be completed and the impact force will be generated, causing the molten pool to be thrown diagonally above.The larger particles will fall into the molten pool, and the smaller particles of liquid metal will fly out of the welding zone, forming a splash.
At the medium parameters, the transition of large particles will occur.As the voltage increases, the arc length becomes longer and the droplet grows larger at the wire end.When the droplet moves in the direction of the melting pool more than the resistance in the direction of its movement, the droplet will break away from the end of the welding wire and generally fall into the melting pool freely along the path slightly deviating from the axis of the welding wire.In the case of strong parameters, namely large current and high voltage welding, the transition of fine particles will occur.At this time, the droplet size is uniform, the transition path is non-axial transition, the arc root diameter is larger than the welding wire tip droplet diameter, and the arc root covers the bottom surface of the droplet.At this point, the necking between the end of the wire and the droplet is accelerated, and the droplet size is reduced.The transition of fine particles will easily result in the widening of the weld,
the thinning of the weld, the welding undercut of the cover surface, the loss of self-protection of the weld pool, the formation of pores or the rapid condensation of the metal, and the hydrogen in the weld without enough time to discharge the pores and other phenomena.
Edit by Ms. Vicky of CSPG
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