High-frequency arc pulse

In recent years, the GTAW welding power source, also known as high-speed switching, has caused arc pulses to exceed 10,000 Hz. Customers of steel pipe processing plants benefit from this new technology. The high-frequency arc pulse causes the downward pressure of the arc to be five times greater than that of the traditional GTAW. The representative improvements brought about also include: the blasting strength is improved, the welding line speed is faster, and the waste is reduced.

The customer of the steel pipe production plant soon discovered that the weld profile obtained by this welding process needs to be reduced. In addition, the welding speed is still relatively slow.

Laser welding

In all steel pipe welding applications, the edges of the steel strip are melted, and when the steel pipe edges are squeezed together using the clamping bracket, the edges solidify. However, the unique property of laser welding is its high-energy beam density. The laser beam not only melts the surface of the material but also creates a keyhole so that the weld seam is very narrow.

If the power density is lower than 1MW/cm2, such as GTAW technology, it will not produce enough energy density to produce a keyhole. In this way, the welding profile obtained by the keyhole-free process is wide and shallow. The high precision of laser welding brings more efficient penetration, which in turn reduces grain growth and brings better metallographic quality; on the other hand, GTAW's higher heat input and slower cooling process lead to a Rough welding structure.

Generally speaking, people think that the laser welding process is faster than GTAW, they have the same rejection rate, and the former brings better metallographic properties, which brings higher blasting strength and higher formability. When compared with high-frequency welding, the laser processing material does not oxidize, which results in a lower rejection rate and higher formability.

The influence of spot size: In the welding of stainless steel pipe factory, the welding depth is determined by the thickness of the steel pipe. In this way, the production goal is to improve formability by reducing the welding width while achieving higher speeds. When choosing the most suitable laser, one must not only consider the beam quality, but also the accuracy of the tube mill. In addition, before the dimensional error of the pipe rolling mill takes effect, it is necessary to consider the limitation of reducing the light spot.