冷拔异型钢管矫直后，要进行初次检查吹灰以确定切头、尾长度。冷拔异型钢管切断的目的是清除具有裂纹、结、疤、撕裂和壁厚不均的端头，以获得要求的定尺冷拔异型钢管，另外切除经检查后不合格难于挽救的缺陷，如内折、内结疤、严重的壁厚不均一等。一般前者的切断在作业线上进行，而后者离线切断

After straightening the cold-drawn special-shaped steel pipe, the initial inspection of soot blowing is carried out to determine the length of the cutting head and tail. The purpose of cold-drawn special-shaped steel pipe cutting is to remove the ends with cracks, knots, scars, tearing and uneven wall thickness, so as to obtain the required fixed-length cold-drawn special-shaped steel pipe. In addition, the defects which are difficult to be remedied after inspection, such as internal folding, internal scarring and serious uneven wall thickness, are removed. Generally, the former is cut off on the operating line, while the latter is cut off off off off-line. 

冷拔异型钢管热处理时保温时间应保证炉内钢管能完全烧透，使其温度均匀，并完成应有的组织转变，从而获得均匀的组织和性能。一般提高加热温度可以适当缩短保温时间。在进行低温退火(包括软化、消除应力及再结晶退火)时，退火温度愈接近于下临界点A1，冷拔异型钢管的回复愈快，消除加工硬化的作用愈完全，因此，保温时间也可以适当缩短。

The heat preservation time of cold-drawn special-shaped steel pipe during heat treatment should ensure that the steel pipe in the furnace can burn through completely, make its temperature uniform, and complete the proper structure transformation, so as to obtain uniform structure and properties. Generally, increasing the heating temperature can appropriately shorten the holding time. When annealing at low temperature (including softening, stress relief and recrystallization annealing), the closer the annealing temperature is to the lower critical point A1, the faster the recovery of cold-drawn special-shaped steel pipe is, the more complete the effect of eliminating work hardening is. Therefore, the holding time can also be appropriately shortened.