The cold-drawn cylinder is made of hot-rolled tube. The selection of the material, specifications and quality of the hot-rolled tube directly affects the drawing process and the quality of the finished product. Pay attention to the following points when selecting materials:
(1) In the selection of materials, generally with low strength and good plasticity, when the strength is guaranteed;
(2) The specifications of the steel pipe should be selected according to the specifications of the finished product to ensure that the elongation is between 20% and 40%; the elongation is too small, the strength of the surface of the finished product cannot be guaranteed, and it is too large, making drawing difficult ;
(3) There should be no serious defects such as pits, cracks, cracks, folds, scars, ellipses on the surface of the material;
(4) It is best to select 0.5 ~ 2a steel pipe after hot rolling. The time is too short, the surface of the steel pipe is shallow and thin, the time is too long, and the surface of the steel pipe is too deep. .