The hardness of crank pin and main journal of crankshaft is of great importance for the satisfactory performance of the crankshaft. In case of low RPM diesel engine, the crankshafts are not hardened and the hardness is achieved by the metallurgical properties. In case of high RPM engine, crankshafts are hardened. The most common process followed by the manufacturers of crankshaft is to go for induction hardening.
Due to seizure of bearings, the temperature goes high and the hardness increases. The increase in hardness makes the crankshaft brittle resulting to the development of crack.
RA Power Solutions Pvt. Ltd. suggests that whenever seizure of bearings takes place it is important that crankshaft hardness is checked and presence of crack should also be checked either by dye penetrant process or Magnaflux.
Author is Managing Director of RA Power Solutions Pvt. Ltd. having almost four decades of hands on experience in providing consultancy, repair and supply of new and reconditioned crankshafts for high capacity diesel engine. More than 2000 crankshaft have been successfully repaired all over the world, some of which were even rejected by reputed engine manufacturers.