Mill Girth Gears

An appropriate mill grade of material in steels (alloy steels and carbon steels), irons (including graded irons, SG iron etc.) or bronze (generally phosphorus bronze) is selected based on the required mechanical properties in case the same is not specified by the client. We provide gears and pinions in cast and forged forms. Various international mill material standards are used including ASTM (USA), AISI (USA), BS (British), JIS (Japanese), GS (German), IS (Indian) standards.

Casting or forging under Gears Pinion Shafts Manufacturers, is produced keeping minimum necessary machining allowances on all relevant and required faces and surfaces. The casting/forging is volume heat treated in special enclosed furnaces with proper temperature controls for attaining the desired mechanical properties. Chemical testing is done using latest spectrometers, mechanical properties derived from test pieces using universal testing machines and hardness obtained using equotip type hardness testers. Non destructive testing to detect internal and surface flaws including Magnetic Particle Inspection (MPI) is carried out once after the casting is heat treated and ready for machining, where as, Ultrasonic Testing (UST) is carried out after proof machining of the job for accurate results.

Joint facing is carried out on all girth / split gears on each side of joints on the two halves on special horizontal floor borers (UNION, SKODA). Appropriate machining allowance is kept for finish machining in case further heat treatment is to be carried out that may create distortion on the job and hence variation in the sizes. In all such cases finish machining is done after the preliminary turning and heat treatment and in some cases even after one round of teeth cutting.