Precision seamless tube

Precision seamless tube is a tube material producing by a cold drawn process with high precision and high-quality finish.

CDS is popular in the hydraulics, being used to make hollowed chrome plated telescopic cylinders and hydraulic rods. It is also popular for large bore, heavy walled, high pressure hydraulic cylinders. Cold Drawn Seamless tubes also find uses in heavy equipment manufacturing such as cranes and garbage trucks.

Due to the characteristics of high-precision, in precision machinery manufacturing, auto parts, hydraulic cylinders, construction (steel sleeve) industry has a very wide range of applications.
General process of cold drawing

A considerable proportion of the seamless tubes and pipes manufactured through the cold roll piercing technology undergo subsequent cold forming. The principal reasons behind cold drawing are:
Achievement of closer wall thickness and diameter tolerance
Improvement in surface finish
To enhance serviceability
No premature failure
Suitable for critical forming Such as 180˚ Bends
Enhancement of mechanical properties of the tube
Expansion of product mix towards the lower end of the OD and wall thickness scales.

THERE ARE THREE BASIC PROCESSES EMPLOYED FOR THE COLD DRAWING OF TUBE:
Hollow drawing
Stationery drawing or floating plug drawing and
Drawing over a mandrel (also known as drawing on-the-bar)

Annealing
After the goods are cold drawn to sizes, the tubes are put on annealing furnace for heat treatment and normalizing.

Straightening
Post annealing, the goods are passed through a seven roller straightening machine to achieve proper straightening of the tubes.

Eddy current
Post straightening, each tube is passed through eddy current machine to detect for surface cracks and other defects. Only the tubes that pass eddy current are fit for delivery to customers.

Finishing
Each tube is either oiled with corrosion resistant oil or varnished for surface protection and corrosion resistant as per customers’ requirement, each tube end is covered by plastic end caps to avoid damage in transit, the marking and specs are put and the goods are ready for dispatch.