Operation of cold drawn steel

① Necessary inspection of raw materials should be carried out before cold drawing. Steel with unknown steel number or without factory certificate shall be sampled for inspection. In case of irregular cross-section of oblate, barbed, hard, wet steel bars, shall not be used for drawing, so as not to damage the drawing die and affect the quality. The steel bar must be treated by rolling and rust removal before cold drawing. The rust removal device can use the reel of the wire drawing machine and the rod rotating frame, in which 3 to 6 one-way staggered or staggered staggered with grooves shell wheel, the steel bar can be repeatedly bent up and down left and right to remove rust. The rust can also be mechanically removed by using a waste wire drawing die of roughly the same diameter as the steel bar.
② In order to facilitate the steel bar to pass through the wire drawing die, the steel bar head should be rolled thin (150 ~ 200 mm long), rolled to the diameter of 0.5~ 0.8mm smaller than the wire drawing die hole, in order to smoothly pass through the die hole. In order to reduce the number of rolling head, the steel bar can be connected by butt welding method, but the convex joint at the weld should be smoothed and smoothed with a grinding wheel to protect the equipment and the drawing die.
③ Before operation, the equipment should be inspected and run without load once according to the routine. When installing the wire drawing die, distinguish between the front and the back. Tighten the fixing bolts after installation.
④ In order to reduce the drawing force and die hole loss, lubricant must be applied when drawing. Generally, a lubrication box is installed in front of the wire drawing die to make the steel bar viscous lubricant enter the wire drawing die.
⑤ The drawing speed should be controlled at 50~70 m/min. The steel bar should not be pulled more than 3 times. If it is necessary to pull again, the internal stress should be eliminated, and the steel bar should be softened by annealing at low temperature (600℃~800℃). After heating, it is taken out and buried in the sand, so that it is slowly cooled, and the cooling rate should be controlled within 150℃/h.
The finished product of wire drawing should be checked at any time for sand holes, grooving marks, skin and other defects in order to replace the wire drawing die or adjust the speed at any time.