Reasons and Prevention Measures of Welds Hole Fissure

Weld seam weld pores not only affect the tightness of erw pipe welds, resulting in pipeline leaks, and will become the trigger point of corrosion, severely reduce the weld strength and toughness.

Welds produce stomatal factors: flux in the water, dirt, scale and iron filings, welding composition and coverage thickness, the surface quality of steel and steel plate edge treatment, welding and steel pipe forming process.

Relevant control measures are:

1. Flux composition. Welding with a suitable amount of CaF2 and SiO2 reacts to absorb a large amount of H2, resulting in highly stable HF-insoluble liquid metal, which prevents the formation of hydrogen voids.
2. Flux accumulation thickness is generally 25-45mm, flux particle size, the density of a small accumulation of thickness take the maximum value, and vice versa to take the minimum; high current, low welding speed accumulation thickness take the maximum value, otherwise take the minimum, in addition, the summer or air humidity is large, the recovered flux should be dried before use.
3. Steel surface treatment. In order to avoid decontamination off the iron oxide scale and other debris into the molding process, the board should be set to clean the device.
4. Steel plate edge treatment. Rust and burr removal devices should be installed on the edge of the steel plate to reduce the possibility of producing stomata. It is best to remove the device installed in the milling machine and disc shears, the device structure is one side of the upper and lower position adjustable gap active wire wheel, the upper and lower pressure plate edge.

5. Weld morphology. Weld forming coefficient is too small, narrow and deep weld shape, gas and inclusions are not easy to emerge, easy to form pores and slag. General weld control coefficient of 1.3-1.5, thick-wall steel pipe to take the maximum, take the minimum thin-walled.

1. Reduce the secondary magnetic field. In order to reduce the influence of partial magnetic blowout, the connection position of the welding cable on the workpiece should be kept away from the welding terminal to avoid that some welding cables generate the secondary magnetic field on the workpiece.
2. Process aspects. Should be appropriate to reduce the welding speed or increase the current, thereby delaying the weld metal melting pool speed, in order to facilitate the gas escape at the same time, if the strip delivery position is unstable, should be promptly adjusted to eliminate frequent adjustments through the front axle or after Bridge to maintain shape, resulting in gas escape difficulties.

A worker from a steel pipe company, which is located in China.