Spiral steel pipes are formed by extrusion of strip steel coils at room temperature, but during the extrusion welding process, the gap between the welds on both sides is not smooth or the gap is too large, which affects its appearance and quality. Therefore, the production of the joints of spiral steel pipes is very important. Common problems and solutions for spiral steel pipe joints.
1. Bubbles.
Bubbles mostly occur in the center of the weld of spiral steel pipes. The main reason is that hydrogen is still hidden in the weld of spiral steel pipes in the form of bubbles. The solution to this problem is to first remove rust, oil, water, and moisture from the welding wire and weld, and then dry the flux well to remove moisture. In addition, increasing the current, reducing the welding speed, and slowing down the solidification speed of the molten metal is also very effective.
2. Sulfur cracks (cracks caused by sulfur).
When welding plates with strong sulfur segregation bands, sulfides in the sulfur segregation band enter the weld metal of the spiral steel pipe and cause cracks. The reason for this problem is that the sulfur segregation band contains low-melting iron sulfide and hydrogen in the steel. The solution to this problem is to use semi-killed steel or killed steel with less sulfur segregation band. Secondly, it is also necessary to clean and dry the weld surface and flux.
3. Thermal cracks.
In the submerged arc welding of spiral steel pipes, thermal cracks can occur in the weld of spiral steel pipes, especially in the arc pits of arc starting and arc extinction. To eliminate such cracks, pads are usually installed at the arc starting and arc extinction, and at the end of the coil welding, the spiral steel pipe can be reversed and welded into the stick welding.
4. Slag inclusion.
The spiral steel pipe includes a part of the slag remaining in the weld metal. Remove the slag on the edges and between the layers of the strip.
5. Poor penetration.
The inner and outer weld metals of the spiral steel pipe do not overlap enough. Adjust the welding current and welding voltage, and adjust the welding speed.
6. Undercut.
The undercut of the spiral steel pipe is a V-shaped groove on the edge of the weld along the center line of the weld. Undercut is caused by improper welding speed, current, voltage, and other conditions. A too-high welding speed is more likely to cause undercut defects than an inappropriate current. Adjust the position or angle of the welding wire, the welding current should not be too large, and fix the welding head.
Post time: May-15-2025