In order to obtain a seamless steel pipe with excellent surface quality, the surface defects of the pipe must be cleaned. Although there are many ways to clear up defects on the tube blanks, the main methods used are flame spade cleaning, manual grinding wheels, automatic grinding wheels and belt cleaning, and turning and cleaning.
(1) Fire cleanup. The equipment is simple, efficient and economical. It is mainly suitable for the surface defect removal of seamless steel tube blanks with a carbon content less than Q.4%. This is because when the tube is cleaned with flame, the tube blank is locally heated, so thermal stress occurs. For billets with high carbon content, hot cracks may occur after the billet is cleaned, even after it has been placed for a period of time, and the quality of the seamless steel tube billet is affected. In severe cases, the billet may be scrapped.
(2) Air shovel cleaning. The equipment is simple, but it is labor-intensive and inefficient. It is not limited by steel. It is suitable for the cleaning of local defects on the surface of bone blanks.
(3)) Manual grinding wheel and automatic wheel cleaning. Mainly used for seamless steel tube blanks that are not suitable for flame cleaning. The manual grinding wheel equipment is simple, the investment is saved, and the operation is flexible, but the labor intensity is large; the automatic grinding wheel cleaning efficiency is high, and currently it is used more.
(4) Using turning or abrasive belts, wheel cleaning. This method of overall grinding and cleaning the surface defects of seamless steel pipe blanks is suitable for the cleaning of surface defects of all kinds of steel pipes, but has low efficiency, high metal consumption, high cost, and is mainly used for high added value and high quality requirements. The surface defects of the first billet (such as stainless steel blanks) are cleaned. It should be pointed out that the surface defects of continuously cast round blanks are generally not removed by the turning method because the fine grained areas of the outer surface layer of the continuously cast round blanks may be turned away, leaving the large columnar crystals exposed. Seamless steel pipe blanks are likely to cause perforated hairs to produce external fold defects when they are pierced.
In short, the inspection and inspection of the quality of the tube blanks and the elimination of the surface defects of the tube blanks are the basic prerequisites for ensuring that the blanks used in the production of seamless steel tubes meet the quality requirements.
