Black Pipe

The welding process of the erw pipe is to use the skin-receiving principle generated by the high-frequency current to heat the edge of the hot-rolled coil to a molten state, and then perform welding by a mechanical extrusion method. The steel pipe produced by the process will have a white fusion line at the center of the weld, and the heat-affected zone on both sides of the fusion line will have a metal flow line extending from the middle to the inner and outer surfaces. Since the erw pipe is made of a base material as a welding material, the performance of the weld seam has a great relationship with the performance of the base material. In ordinary materials, the ductile-brittle transition temperature curve of the weld and the base metal. In ordinary materials, the difference in absorbed energy values between the weld and the base material in the Charpy impact test is small. On the contrary, there is a big difference in the high toughness material, and the weld impact toughness is obviously inferior to the base metal, but it is obviously superior to the weld of the ordinary material.

A square tube is a long bar of steel that has a hollow interior. It got its name from its square cross-section. Since it's made of steel, it's highly durable. It's likewise resistant to corrosion, rust, and stains. These tubes can even withstand acid, salt water, and chemical exposure.

This type of tube is divided into two categories — seamless steel pipes and welded steel pipes. As its name suggests, a seamless steel pipe has a smooth and unobstructed composition and lacks any welds on the surface. Meanwhile, a welded steel pipe has a bent steel plate that is welded into a square shape, creating a seam on the pipe’s body.