In the year 2008, we added Electric Resistance Welded Stainless Steel Tubes in our product range, and began to effectively serve diverse applications in various industries. These tubes are manufactured from high grade steel procured from Steel Authority of India Ltd. (SAIL), a government of India undertaking. At the well equipped manufacturing facility, our team carries out the following processes to craft this excellent product. The production process is as follows:
The mother tube is formed on the tube mill, using quality stainless steel strips. To ensure excellent quality of welding, TIG multi-electrode welding technique is used. This welding process involves 100% fusion along with argon purging, and no filler metals are added during this operation.
These tubes are solution-annealed in a continuous annealing furnace at a temperature range of 1060-1100OC. As soon as these are removed from the furnace, the tubes are quenched in a coolant to eliminate any chromium carbide precipitation that may be formed on the tubes. The annealing process facilitates:
- Removal of stress induced during tube forming and cold drawing
- Sufficient ductility and softness for cold drawing
- Transformation of the weld zone to austenitic nature
- Re crystallization of metallic grains to original form and thereby improving corrosion resistance
In the annealing process, scales are usually formed on the surface. These scales are removed by pickling the tubes, and then dipping the tubes in a hot pickling solution made of nitric acid, sulphuric acid hydrofluoric acid.
After dipping, a coating of appropriate lubricants is applied on the tubes, which are cold drawn on a drew-bench afterwards. This is done for the following reasons:
- To vary the metallurgical structure and restore the properties to the parent material
- To achieve a tube having closer dimensional tolerances
- To produce tubing of smaller size and wall thickness
- To reorient the grain structure of weld portion with that of the parent material
- To remove/minimize the internal bead
After the drawing process, the tubes are annealed and pickled, which allow the tubes to retain the properties of the parent material. Then, the tubes are treated to provide corrosion resistance properties. The last stage involves the electric marking of the tubes, indicating material grade, size and manufacturing standard.
Their application areas include dairy & food products, boilers, railway coaches and ships. This range successfully serves industries such as:
- Pharmaceutical
- Chemical
- Sugar
- Metallurgical
- Oil & Gas
- Instrumentation
- Pulp & Paper
- Automobile
- Fertilizer
