Our choice of machinery relates directly to the stages of production and the quality control process. We have a full-fledged Laboratory comprising all the analytical equipment required to determine the right quality & composition of raw materials. All furnace additions are duly analyzed and pre-treated here. Special molding techniques have been developed to improve upon the roll quality for chill as well as the other rolls. The high-quality scrap (with controlled sulfur & phosphorus and other raw materials), once tested, moves to the latest designed Induction Melting Furnace for a clean and homogeneous melt of proper composition.
Proper temperature control during the course of the heat and at the time of pouring of the roll is exercised with the help of Immersion and Optical Pyrometers. A bath sample of each melt is analyzed for composition and determination through the latest model of a German Spectrometer. Every possible precaution is taken to minimize hydrogen. The process guarantees a uniform structure & mechanical properties over the particular zone. Rolls then move to our large Machine-Shop, where each roll first passes through a series of heavy Roll-Turning Lathes for Proof Machining.
At this stage, various tests are carefully carried out to determine if the roll is zero-defect and qualifies for further processing. Hardness Testing and a series of Metallographic and Mechanical tests monitor the structural homogeneity and ensure that rolls are free from cracks, blowholes, gas holes, etc. Hardness is measured using the Equitop Hardness Tester.
The rolls meeting all the stringent tests to our complete satisfaction are then sent to the rest of the machine-shop, comprising High Precision Lathes, Radial Drill Machines, Boring Machines, Wobbler Milling & Grinding Machines, etc.
Meanwhile, all the steel rolls require heat treatment. The Hardening and Tempering furnaces are provided with Temperature Control Microprocessors, and the required rolls are subjected to various heat treatment cycles. Stress Relieving of Acicular S.G. Rolls is also done here.
Metallurgical tests in respect of grain size and microstructure are carried out after heat treatment, and eventually, Ultrasonic Testing is done, where required, to ensure the overall internal soundness of the roll. Hollow rolls are dynamically balanced at different RPMs to ensure their friction-free movement. Finally, the rolls, as required, are tested by means of Non-Destructive Testing methods like Ultrasonic, Magnetic Particle Inspection, and Dye-Penetration Tests to ensure the best possible quality of roll without surface and internal defects.
For large or critical rolls, samples are removed from the rolls to carry out Tensile, Impact, and Microstructure tests to ensure optimum properties in service.
Roll material and groove design are major factors affecting rolling performance and roll life. It is after these series of tests and quality control processes that we finally present our rolls for the ultimate inspection, approval, and delivery. Rolls are always dispatched with the identity number engraved on the drive-end wobbler face.