Explanation

Refers to steel pipes with relatively small diameters, usually within the range of 0.1-5mm in diameter. The larger diameter capillary tube can be produced by cold drawing or cold rolling, while the smaller diameter capillary tube can only be produced by cold drawing. For example, stainless steel capillary tube tubes with a diameter of less than 1mm for injection needles are produced by cold drawing. The main processes of producing capillary tube tubes by cold drawing include: core threading, cold drawing, loosening, stripping and annealing treatment. The long mandrel is generally made of high-strength wire. Place the tube material on the long core rod. It is drawn together by the drawing die. After being pulled out, the rod is loosened by the rod loosening machine to create a gap between the steel pipe and the core, and then the core rod is taken out. Due to work hardening of materials during cold working, annealing and bating treatment shall be carried out before re drawing when the steel pipe still needs to be drawn before reaching the finished size. Because the steel pipe is small, it is not convenient to remove the scale with pickling, so annealing treatment usually uses non oxidizing heating or rapid electric heating methods.

Classification