The ratio of the pulling effort and the limit of the tug of the material should not cause ruptures in the part of the wire that has already passed through the filter, therefore, from one passage, a reduction in the diameter can only be obtained to 0.9 from the original (with soft steels).
This figure determines the number of passages according to the given initial and final diameters. The output of the material during drawing along the length (hood) is easily calculated by the ratio of the area of the initial and final sections, for example, when haul from 6 to 4 mm, the length increases 2.25 times with simultaneously strengthening by 60-80%.
Small their own installations for cold overthrow at the factories of prefabricated reinforced concrete parts are not complicated and consist of a dragging working tool (winning filters), “turntables” for unwinding a roller and a pulling device (motor, gearbox and winch). Cold sticking is preceded by pre -processing rollers to remove ward and rust from the surface of the metal, causing premature wear of the filters that violate the release process and give reduced quality and marriage of the material. When pre-processing, the katanka in skeins is consistently subjected to etching with a weak solution of sulfuric acid (concentration depending on the temperature, section and brand of steel) with heating up to 50-60 °, washing water, neutralizing the residues of the acid with lime water, heated up to 40-50 °, repeated final flushing with water and drying. A trafficking and dried katanka is passed sequentially through filtering with holes of 6.2; 5.7; 5.2; 4.7; 4.2 mm. To reduce friction, soap lubrication is used. Shown a scheme of a small simplified installation for drawing. Its performance depends on the specified drawing parameters and is from 2 to 3 g per day.
