Manufacturing Procedure for Pipes / Tubes
HR Coils for production of pipes will be procured from SABIC/ JSW/ TATA or any other approved vender.
The steel shall be of fully killed, with grain size ASTM 7 or finer as per ASTM E 112.
Mechanical properties of HR Coil material shall confirm to TDC of raw material / applicable standard.
Slit is passed through horizontal and vertical forming rolls to receive a defined diameter open edge round pipe suitable for welding.
At the final stage of forming, rolls are provided with guide fins to have a proper proportionate gap & correct entry in welding roll.
The performed shape of pipe is finally passed through welding heads ‘V’ edges controlled by the seam guide. The welding process is ERW with high frequency induction welder.
The fusion takes place through five roll assembly set at the Mill which ensures proper welding.
Bead scarfing shall be done as per applicable standard & Client specification.
Welding parameters, like-current, voltage, welding speed and heat treatment temperature shall be monitored.
The welding temperature shall be adequate to form weld. By controlling various controlling parameters, desired welding quality is achieved.
Seam normalising is carried out on weld and HAZ after the welding. The normalising equipment is based on medium frequency. Seam normalising temperature is monitored by the non contact temperature indicator.
The water cooled pipe is passed through a set of sizing roll which controls the ovality and required dimensions stipulated in respective specification. This is finally verified by measuring gauge.
The pipes are cut to length by cut of carriage (COC) as per client requirement.
Cut cleanly and nominally square with the axis of the pipe and free from burrs.
Each pipe is transferred to end preparation stand where both ends of the pipe are bevelled at an angle 30,-0/+5 degree with root face 0.063” ± 0.031” (1.60mm, ±0.80mm).
Pipes are taken from mill as per plan. Clean the internal dia of pipe properly to avoid any chips and ID bead. The requirements (test pressure & holding time) are verified as per applicable standards.
Pipes are checked for any leakage during testing.
Dimension of pipe shall be measured by calibrated gauges and acceptance as per the applicable standard.
The relevant marking stipulated in applicable standard / specification shall be Paint / Inkjet stencilled on each length of the pipe.
Additionally, the pipes shall be bundled as per Client requirement and each bundle tagged with permanent & legible label at both end.
Sufficient care should be exercised while storing, packing and handling of products. While storing and transporting them, adequate ventilation should be provided. It is necessary to store galvanized pipes with space in between them.
Materials testing like Flattening Test, Tensile Test, Impact Test, Metallographic Test & Chemical analysis are carried out as per work instruction / applicable standard. Result of the same is recorded.