One, the production and manufacturing of hot-rolled seamless tubes generally employ fully automatic tube-rolling mills. Surface defects of solid billets are inspected and eliminated, length requirements are trimmed, and safety is ensured on the end faces where the billet may crack. Afterward, the billet is heated in a heat treatment furnace and cracking is guaranteed on the cutting machine. As the hole breaks continuously rotates forward, under the action of the hot rolled strip steel and the top edge, the internal cavity of the billet slowly forms, known as a rough tube. A second cold rolling is conducted on the fully automatic tube-rolling mill. Subsequently, the entire tube is uniformly sized using wall thickness and sizing machines to meet the specifications and models. Using a rotating tube-rolling mill to produce hot-rolled seamless tubes is a good production method.

For smaller diameter, higher quality seamless tubes, it's essential to opt for cold rolling, cold drawing, or a combination of both. Cold rolling is typically performed on a two-roll extrusion machine, where seamless steel tubes are cold rolled within a ring die that consists of a variable cross-sectioned circular slot and a stationary conical top edge. Cold drawing operations are usually carried out on a multi-strand or double strand cold drawing machine with a force range of 0.5 to 100T.

The extrusion method involves placing a warm tube blank into a sealed extrusion cylinder and using an extrusion die to perform a workout, forcing the extruded piece out through a smaller die hole. This invention can produce small-diameter seamless steel tubes.

The main applications of seamless tubes are extremely diverse. General seamless tubes are mainly cold rolled from plain carbon steel, low-alloy tool steel, or alloy tool steel, with high production capacity, primarily used as pipelines for conveying liquids or structural components.

Based on different primary uses, there are three types of supplies: a) supplied by composition and physical properties; b) supplied by physical properties; c) supplied by compression test. Seamless tubes supplied at grade a or b are also required to undergo a compression test when subjected to liquid pressure.

Professional uses mainly include seamless pipes for heating furnaces, geological environments, crude oil, and more.

Seamless pipes can be categorized into various types, such as hot-rolled, cold-rolled, cold drawn, extruded, and others, based on different production and manufacturing processes.

Based on the classification of appearance design, there are circular tubes, special-shaped tubes, etc. In addition to rectangular square tubes, there are also stainless steel round tubes, semi-circular tubes, triangular tubes, hexagonal tubes, convex tubes, plum blossom-shaped tubes, and more.

According to different materials, they are categorized into ordinary carbon structural pipes, alloy structural steel pipes, carbon structural pipes, aluminum alloy structural pipes, and stainless steel structural pipes, etc.