The wall thickness of the cold-drawn pipe should be uniform, and there should be few defects on the inner and outer surfaces; it is necessary to equip the outer surface polishing and inner hole defect finishing equipment. Compared with the ordinary cold-drawn steel pipe, the cold-drawn pipe production increases the hot-rolled capillary pickling and re-inspection process. The main purpose is to ensure that the outer surface of the capillary tube has no defects such as folds and cracks, and to eliminate the capillary tubes with defects such as folds, serious scribes, and pockmarks on the inner surface.
Cold-drawn pipe is a very important process in the production of all cold-drawn pipes. The quality of annealing affects both the performance of the steel pipe and the removal of iron oxide scale. Cold-drawn pipes need to be equipped with non-oxidative bright annealing furnace equipment, pickling and cold drawing In the process of sulfuric acid pickling, the tube is easy to form "black slag" mainly composed of Fe2O3 and Fe3O4, which will form black spots on the surface in the subsequent production.
The smoothness of the cold drawn pipe should be made of resin as the lubricating agent. This smoothness is significantly different from phosphating and smoothing (saponification). The drawn steel pipe has the true color of the iron matrix, which has both high smoothness and cold rolling. Tube-like beautiful appearance shade.