Manufacturing procedure

A heated billet is brought into contact with tapered revolving rolls in such a way that the billed is pulled into the space allowed between the rolls. The mandrel is placed in the space. The soft center of the billet makes it possible for the rolls to draw the billet over the mandrel, producing a hollow shell. When the billet has entirely passed over the mandrel, it is in the form of a thick walled seamless tube. The heavy walled tube is then passed to a rolling mill which reduces the tube to piping of proper outside diameter and wall thickness. Depending upon the process condition (temperature), seamless tube/pipes is termed as Hot Finish Seamless or cold drawn seamless as the term implies.

Advantages

• Cold-Drawn Seamless Tubing: Cold drawn tubing inherently possesses a high strength-to-weight ratio and can be processed to provide a combination of desired characteristics, dimensional accuracy, good surface quality, excellent micro-structure uniformity, good machinability and high tensile properties. It is also suited for such post-treatments as carburizing and heat treating.
  
  
• Hot-Finished Seamless Tubing: This type of tubing is normally used in applications where precise dimensions and surface quality are secondary considerations, or where finish and final mechanical qualities can be obtained through machining and heat treatment.

Standards

ASTM A519
Specification for seamless carbon and alloy steel mechanical tubing

Standard Steel Grades

1008, 1010, 1017, 1020, 1026, 1035, 1040,
1516, 4130, 8620 , ST 52.3

Others available upon request