Development History of Types of and Manufacturing Equipment for Domestic Ultra Large-sized Hot-rolled Seamless Steel Tube

Described here in the paper is the development history of the types of and the manufacturing equipment for the domestic ultra large-sized hot-rolled seamless steel tube. Also analyzed are the characteristics of the manufacturing process of the said tube. It is regarded that although the extrusion mill is capable of producing the carbon steel tube, the alloy steel tube, the stainless steel tube, the hi-temperature alloy steel tube and the corrosion-resistant alloy steel tubes, the production costs are rather high;the 2-roll rotary rolling mill is capable of producing the carbon steel tube, and the alloy steel tube with high productivity and high product accuracy, however certain difficulties stay with such mill in case of rolling tubes of hi-alloy steel, stainless steel, hi-temperature alloy steel and corrosion-resistant alloy steel;and compared with the rotary rolling mill, the pilger mill is suitable for a rather wider steel tube type range, and features bigger rolling deformation, but the product accuracy is rather low. Accordingly, the billet-supply solutions for different rolling mills to make the ultra large-sized hot-rolled seamless steel tube is proposed.