Technology of Steel Tube Making

Abstract

The manufacture of steel tubes which are used for a wide range of applications, involves large variety of prod-uction processes. Depend-ing upon the end use and econ-omics, different processes used for steel tube making can be classified broadly into two distinct groups: (a) Welded, and (b) Seamless Under the category of welded tubes, the two main processes available are (i) Electric Resistance Welding (ERW/HFIW) and (ii) Furnace Butt Welding (HFW/Fretz Moon). Electric Resistance Welded tubes are manufactured using direct or high frequency induced current in formed circular hot or cold rolled steel. strips. This process has also undergone remarkable advan-cement in the technology in terms of both production and quality, in the recent past. Furnace Butt Welding is effected by pressure welding, where the entire strip is heated in a tunnel furnace and the edges are further heated to a temperature near fusion point & then pressed together. This process is also called as Fretz Moon Process. Under the category of seamless process, the three main stages involved are piercing, elongation and sizing/ stretch reducing. Over the years considerable developments have taken place in the area of seamless tube making to improve the process with respect to yield, wall thickness tolerance, diameter to thickness ratio and towards manu-facturing tubes of larger variety of steel grades.