According to different production methods (or processes), seamless steel pipes can use steel ingots, continuous casting billets, rolling billets, forging or centrifugal casting hollows, etc. as blanks. Since the quality of the tube blank largely determines the quality of the seamless steel pipe, the preparation of the tube blank is particularly important.
Tube blank preparation includes the selection of tube blank types and specifications, chemical composition and organization inspection, surface defect inspection and cleaning, cutting, centering, etc.

1. Classification of seamless steel pipe billets
Seamless steel tube billets can be classified according to the treatment method, chemical composition, forming method, and use conditions of the steel tube. For example, according to the treatment method, it can be divided into electric furnace steel pipe billet, converter steel pipe billet and electroslag steel pipe billet; according to the forming method, it can be divided into steel ingot, continuous casting pipe billet, forged pipe billet, rolled pipe billet and centrifugal cast hollow pipe. According to chemical composition, it can be divided into carbon steel tube billet, alloy steel tube billet, stainless steel tube billet and corrosion-resistant alloy tube billet, etc.; according to the purpose and use conditions of steel tube, it can be divided into general structural tube and fluid conveying tube billet, boiler tube Pipe blanks, pipe blanks for petroleum drilling and geological drilling, pipe blanks for chemical and fertilizer plants, bearing pipe blanks, and other special-purpose steel pipes are broken.

2. Seamless steel tube billet selection
The selection of seamless steel tube(astm a106 steel pipe) billet includes the choice of steel grade, specification, smelting method and forming method.
The choice of steel grade, treatment method, and forming method is based on product standards or ordering technical conditions. The selection basis of the billet size is to find the corresponding billet size in the rolling table according to the size of the steel pipe.
Generally speaking, seamless steel pipe plants will use refined converter steel or electric furnace steel for continuous casting round billets.
When steel grades or specifications cannot be cast continuously, molten steel ingots or centrifugal casting are made into hollow round billets. When the size of the tube blank cannot meet the compression ratio requirements, a larger size tube blank can be selected to become a tube blank that meets the size requirements after rolling or forging. The calculation formula of compression ratio is as follows: K=F, 1F where K-compression ratio; F,-cross-sectional area of tube blank, mm'; F-cross-sectional area of steel pipe, mm'.
When there are strict requirements for the uniformity of the tube blank composition, the content of inclusions or the gas content, the electroslag tube blank or the tube blank smelted in a vacuum degassing furnace are generally used.

If the capacity of the piercing machine cannot meet the requirements of the piercing process, or the perforation is likely to be folded inward, mechanical processing can be used to drill a 460-200mm through hole along the center of the tube blank. The size of the center hole depends on the size of the tube blank and the capacity of the punching machine. The larger the diameter of the tube blank, the larger the center hole; the greater the capacity of the piercer, the smaller the center hole.