In the process of high-frequency welding of steel pipe, the welding process and the control of process parameters, the location of the induction coil and the location of the resistance of the weld pipe weld quality have a great influence.
1) Control of the gap of the steel pipe，the steel strip enters the welded pipe unit and is formed by the forming roll. After the guide roller is oriented, the circular steel pipe tube with the opening gap is formed, and the extrusion amount of the squeeze roller is adjusted so that the gap gap is controlled at 1 ~ 3mm, and make both ends of the welding flush. Weld gap control too large, will weld poor welding and produce no fusing or cracking; weld gap control is too small, due to heat is too large, resulting in weld burning, melting metal splash, affecting the weld quality of welding.
2) The induction of high-frequency induction coil should be placed in the same center line with the steel pipe, the front end of the induction coil from the squeeze roller centerline distance, without burning the squeeze roller under the premise of steel pipe specifications should be As close as possible. If the induction circle is far from the squeeze roller, the effective heating time is longer, the heat affected area is wide, so that the strength of the steel pipe weld is not broken or not penetrated; otherwise the induction circle is easy to burn the squeeze roller.
3) The resistance of the position of the regulator is a tube or a group of special pipe, the cross-sectional area of the resistor should not be less than 70% of the cross-sectional area of the pipe diameter, the role is to make the induction coil, rods form an electromagnetic induction loop, resulting in proximity effects, eddy current heat concentrated in the vicinity of the edge of the pipe weld, so that the edge of the tube heated to the welding temperature. The resistor should be placed in the V-zone heating section and the front end is at the center of the squeeze roller so that the centerline coincides with the centerline of the tube. Such as the location of the resistance device is not good, affecting the welding speed and welding quality, so that steel pipe cracks.
4) High-frequency welding process parameters - the input heat control high-frequency power input to the steel pipe weld part of the heat is called the input heat.
