Titanium welded pipe processing generally has the following four methods:
1. Sheet-welded
titanium tube: Compared with the multi-slit "shrimp" type, this titanium tube has fewer welds, but the more complicated the sheeting process, it requires a large number of molds, consumes more materials and processes, and has fewer welds. It will also affect the corrosion resistance, and the 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 rolled into multi-section unfolded material under the plate, and then rolled and welded. This method has a lot of leftover material and a large amount of weld seam. Because the welding seam 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 pipeline transmission resistance and increases the erosion corrosion of the back and reduces the service life.
3. Stamped titanium welded pipe: The appearance of this titanium pipe seems to be the same as that of the push-made titanium pipe, but the processing technology is to stamp the tube blank in the stamping die on the song dynasty. During the forming process, the back of the titanium pipe is pulled, and the back is forced to pull thin, the inner pipe wall is thickened due to pressure, resulting in uneven wall thickness or wrinkling, and the back of the titanium pipe is subjected to erosion and corrosion during use. Because the back wall is thin and easy to wear early, 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) cannot match the pipe wall thickness (2mm~4mm), which increases the transmission resistance, and the surface finish is poor. More importantly, there are internal A large number of defects such as pores caused by manufacturing seriously affect the corrosion resistance and service life.
The above several titanium tubes are far from meeting the current requirements. The reason why the push-made titanium tube is quickly accepted and welcomed by users is because the push-made titanium tube has its own characteristics.
The processing of titanium welded pipe is to use the seamless titanium pipe as the billet, and the billet whose pipe diameter is smaller than the finished product is used to push and extrude the billet on the special push extrusion machine. During the forming process, the pipe billet expands. Stress analysis shows that the stress in different parts is different, but under bidirectional compression, that is, under axial compression, radial compression and circumferential tension, the stress is always in tension.
