Causes and Solutions of Honing Pipe Pits

The pitted surface of the quilted tube is also called pitted surface, because the product surface is rough and uneven. Most of them are continuous, and some are locally or periodically distributed. The causes of pitting are:

1. The finished hole or the rolling groove of the front hole of the finished product is worn, or there is broken iron oxide scale stuck;

2. Broken iron oxide scale falls off after being pressed into the surface of rolled piece;

3. Roll corrosion;

4. The surface of the billet is seriously oxidized during heating.

The methods to remove the pits in the quilting tube are as follows:

1. When changing the roll, check the roll first, do not use the seriously rusted roll, and replace the worn roll or pass in time;

2. Improve the roll material, maintain good cooling of the rolling groove, and use process lubricant (see Plastic Machining Process Lubrication) to enhance the wear resistance of the rolling groove;

3. Control the billet heating operation to maintain positive pressure in the furnace and reduce oxidizing gas. For some alloy steels that are easy to oxidize and the oxide scale is not easy to fall off, the billet surface shall be covered with iron scale for protection and heating;

4. Remove the scale on the surface with high-pressure water, compressed air or iron brush before roughing mill.