Characteristics And Process Flow Of Cold Working Steel Pipe

Cold steel pipe processing, including cold rolling, cold drawing, cold tension reducing and spinning, is the main method to produce precision thin-wall and high strength pipe. Among them, cold rolling and cold drawing are commonly used high efficient production methods of cold working steel tube.

Compared with hot rolling, cold processing has the following advantages: it can produce large-diameter thin-wall pipes; High precision of geometric dimensions; High surface finish; With the corresponding heat treatment system, it can obtain high comprehensive mechanical properties: it can produce all kinds of special-shaped and special-section materials and some materials with narrow hot-working temperature range, low high temperature toughness and good room temperature plasticity. The outstanding advantage of cold rolling is strong wall reduction ability. The performance, dimensional accuracy and surface quality of incoming material can be improved significantly. Cold drawing has lower pass reduction rate than cold rolling, but the equipment is simpler, the tool cost is less, the production is flexible, and the product shape and specification range is larger. Therefore, reasonable combination of cold rolling and cold drawing is needed on site. In recent years, cold tension reduction, cold processing of welded pipe and cold drawing process of super long pipe can improve the output of the unit. Expand the range of varieties, improve the quality of weld seams, provide suitable pipe materials for cold rolling and cold drawing. In addition, warm processing in recent years has been paid more attention to, usually induction heating to 200-400℃, so that the plastic tube billet. The maximum elongation of warm rolling is about 2-3 times that of cold rolling. Lukewarm break to blade shrinkage rate increased by 30%, so that some low plasticity, high strength metal may also be finished.

Although the specification range, dimensional accuracy, surface quality and microstructure of cold-processed tubes are better than those of hot-rolled tubes, there are four problems in their production: Cycle number is much, production cycle is long, metal consumption is big, intermediate processing process is complex, all sorts of steel pipe because its material is qualitative, technical condition, specification is different, its production craft flow and craft system also differ somewhat, but in general by the following main working procedure composition:

1) Pre-processing of cold working, including preparation of size, shape, microstructure and surface state;

2) Cold processing, including cold drawing, cold rolling and spinning, etc.

3) Steel pipe finishing, including heat treatment, cutting, straightening and inspection of finished products, etc