In the construction of the national economy, hot-rolled seamless steel tubes are a crucial category of steel products, serving as an irreplaceable and highly secure basic raw material in key sectors such as oil and gas drilling and extraction, as well as equipment manufacturing.
The production process of hot-rolled seamless steel tubes is characterized by two typical features. Firstly, the deformation resistance during the piercing and rolling of solid billets is significant, necessitating the completion of the forming process at a higher deformation temperature than other hot-rolled steel products. Secondly, the steel tubes are cooled in the air after rolling, lacking effective control over the cooling path.
Surface defects on billets, including scabs, pits, grooves, cracks, etc., are typically inspected visually by personnel (or through non-destructive testing methods if specific requirements are present). Afterward, these defects are thoroughly cleaned. To prevent missed inspections, surface inspections and cleaning can also be conducted after the billet has undergone pickling or shot blasting (sandblasting) to remove surface mill scale.
There are three primary methods for cleaning billet surface defects: flame cleaning, grinding with abrasive wheels, and turning. For carbon steel billets with low crack sensitivity, flame cleaning is employed. For steel grades with higher crack sensitivity, such as high-alloy steel billets, grinding with abrasive wheels is used. For some special steel grades, including stainless steel and corrosion-resistant alloy billets, surface turning or peeling is necessary for cleaning.
