How are seamless steel pipes made? What are the theoretical weight specifications of seamless steel pipes?
   A steel pipe made of a whole piece of metal with no seams on the surface is  called a seamless steel pipe . Seamless steel pipes have a  hollow cross-section and are widely used as pipelines for conveying fluids, such  as pipelines for conveying oil, natural gas, coal gas, water and certain solid  materials. According to the cross-sectional shape, seamless steel pipes are  divided into round and special-shaped ones. Special-shaped pipes have square,  oval, triangle, hexagon, melon seed, star, winged pipes and many other complex  shapes. The following is a complete table of theoretical weights of seamless  steel pipes, seamless steel pipe sizes and allowable deviation tables.    How are seamless steel pipes made?    1. Main production process of hot-rolled seamless steel pipes (△ Main  inspection process):    Pipe blank preparation and inspection△→Pipe blank heating→Pipe  perforation→Pipe rolling→Steel pipe reheating→Sizing (reducing) diameter→Heat  treatment△→Finished pipe strai...