Weld hole refers to the cavity formed by the gas remaining in the weld pool before the solidification of the metal during welding. The gas may be absorbed by the molten pool from the outside, or it may be generated by the reaction in the welding metallurgy process.
First, the reason for the production of air holes in the welded pipe weld
1. Whether the groove surface of the welded part is clean;
2. Is the welding current too large;
3. Whether the welding voltage and arc are too high;
4. Is the welding speed too fast;
5. Whether the humidity of the welding environment is too large;
6. Is the purity of argon insufficient?
Second, the preventive measures for the weld hole generated by welded pipe welding:
1. Flux composition. When the solder contains an appropriate amount of CaF2 and SiO2, it absorbs a large amount of H2 and generates HF which is highly stable and insoluble in the liquid metal, thereby preventing the formation of hydrogen pores.
2. The deposition thickness of the flux is generally 25-45mm, the flux particle size is large, the density is small, the stacking thickness takes the maximum value, and the minimum value is taken; the large current and the low welding speed stacking thickness take the maximum value, and vice versa, the minimum value, in addition, summer Or when the air humidity is high, the recovered flux should be dried before use.
3. Surface treatment of steel plates. In order to avoid the inclusion of iron oxide skin and other debris falling off the unwinding, the surface cleaning device shall be provided.
4, steel plate edge treatment. Rust and burr removal devices should be installed on the side of the steel plate to reduce the possibility of generating air holes. The position of the cleaning device is preferably installed after the edge milling machine and the disc cutter. The structure of the device is a two-side active wire wheel with adjustable clearance on one side, and the upper and lower sides of the plate are pressed.
5. Weld appearance. The forming coefficient of the weld is too small, the shape of the weld is narrow and deep, and the gas and inclusions do not easily float out, and the pores and slag are easily formed. Generally, the weld bead forming coefficient is controlled at 1.3-1.5, the thick-walled welded pipe takes the maximum value, and the thin-walled pipe takes the minimum value.
6. Reduce the secondary magnetic field. In order to reduce the influence of magnetic partial blow, the connection position of the welding cable on the workpiece should only be far away from the welding terminal, and the partial welding magnetic cable can be prevented from generating a secondary magnetic field on the workpiece.
7, the process. The welding speed or current should be appropriately reduced to delay the crystallization rate of the weld pool metal to facilitate gas escape. At the same time, if the strip delivery position is unstable, adjustment should be made in time to prevent fine adjustment of the front axle or rear. The bridge remains shaped, making gas escape difficult
Plastic Coated Composite Pipe
Plastic coated composite pipe is on the inner wall of the steel melts to dissolve a thickness of 0.5 ~ 1.0 mm layer of polyethylene (PE) resin, ethylene - acrylic acid copolymer (EAA), epoxy (EP) powder, non-toxic polypropylene (PP) or non-toxic polyvinyl chloride (PVC) and other organic matter and constitute a steel-plastic composite pipe material.
Advantage
Plastic coated composite steel pipe is protected by plastic coating both inside and outside. In the middle, it is used to strengthen the composite structure of welded steel pipe or seamless pressure steel pipe, which overcomes the defects of easy rust, corrosion, high pollution, low strength and deformation of plastic pipe, and integrates the common advantages of steel pipe and plastic products. it not only has steel tube high strength, easy connection, water resistance and other advantages, also overcomes the steel easy to corrosion, under the influence of water pollution, scale and strength of plastic pipe is not high, poor fire performance shortcomings, design life of 50 years.
Packaging Details
Plastic caps on both ends, Steel bundle, Woven bag or acc. to customers' request.
Delivery Time
15 days after receiving deposit
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Plastic Coated Composite Pipe
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