Titanium welded pipes generally have the following four processing methods:
1.Sheet welded titanium pipe: Compared with the multi-slit "shrimp" type, the titanium pipe has fewer welds, but the sheeting process is more complicated, requires a lot of molds, consumes more materials and processes, and welds Corrosion resistance is also affected and appearance is not ideal.
2.Multi-weld type (commonly known as "shrimp waist" type) titanium tube: its processing technology is complicated. Usually, the tube is cut into multi-section oblique openings, welded or formed into multi-section unfolded materials under the plate, and then rolled and welded. The method has a lot of leftover material and a large amount of welds. Because the weld will greatly reduce the corrosion resistance, it is easy to leak, and the appearance is not good. The inner surface is a folded surface, which increases the transmission resistance of the pipeline and increases the erosion corrosion of the back and reduces the service life.
3.Stamped titanium welded pipe: The appearance of this titanium pipe does not seem to be different from the push-made titanium pipe, but the processing process is to stamp the tube blank in the punching die. During the forming process, the back of the titanium pipe is pulled and forced to pull the back. Thin, the inner tube wall is thickened under pressure, resulting in uneven wall thickness or wrinkling, and the back of the titanium tube is subject to erosion and corrosion during use. Because the back wall is thin and prone to premature damage, the overall life of the tube is greatly reduced.
4.Cast titanium tube: Although it is a seamless titanium tube, the wall thickness (at least 5mm) and the pipe wall thickness (2mm~4mm) cannot match, thus increasing the transmission resistance, and the surface finish is poor. More importantly, there are a large number of internal Defects such as pores caused by manufacturing seriously affect the corrosion resistance and life.
The above titanium tubes are far from meeting the current requirements, and the advent of push-made titanium tubes is quickly accepted and welcomed by users because push-made titanium tubes have their own characteristics.
The processing of the titanium welded pipe uses the seamless titanium pipe as the blank. On the special push extrusion machine, the blank with the pipe diameter smaller than the finished product is used for extrusion molding. During the forming process, the pipe blank expands. Stress analysis shows that the stress in different parts is different, but under bidirectional compression, namely axial compression, radial compression and circumferential tension, the stress is always in tension.