The reasons why the surface of seamless steel tube has S shaped bending

The S bending of the surface of the seamless steel pipe is caused by two different colors of the spiral steel surface after grinding. There are many factors contributing to this situation. Let's take a detailed look below.

1. Precision seamless tube perforation tube is too long, in order to improve the life of the head, the inner cooling water will increase, but the capillary produces spiral and Yang surface, and the surface of the capillary is two obvious red and black temperatures, which is the cause of the difference in the size of the spiral diameter.

During the cold drawing and finishing mill, two kinds of red and black temperatures have been found on the surface of the steel tube, resulting in the uneven hardness of the steel. Therefore, when the metal extends, it will produce unsynchronized, black wall thickness, red wall thickness, black outer diameter, and red outer diameter. Generally wear precision seamless steel tube blanking 0.9-1 meters, so that the head cooling water control point, is conducive to the surface of the blank is not easy to appear Yin and Yang surface.

2. The hole at the front end of the perforator should be tightly pressed and there is no oscillation. Bite into the tube, the tube tail produce swinging, head piercing, swing, resulting in capillary wave uneven, and the uniformity of the wall thickness is not allowed, the same feeding diameter can not be too large, which will lead to the tube tail swinging. The general feeding diameter is 15 millimeters larger than the tube blank, so the tube billet is more stable when the tube billets bite.

3. Centering roll is adjusted. When the tube is close to the first centering roll, the tube is about to be opened so that the capillary enters the first centering roll, and then it is close to the centering roll and entering the centering roll. In this short time, the top rod will be unstable when the top is adjusted to the lower when the second centering rolls are adjusted to the lower. When the capillary is close to the first centering roll, open, the capillary will sink down, enter the centering roll, and the capillary will go up again, so a low one liter, the top here is also low and a liter, so that the capillary will produce uneven thickness of the wall.

The above is the cause of the S bending of the surface of the precision steel pipe. We concluded that the operation is not rigorous in the production process, so we need to strengthen technological processing.