Environmental Friendly Controlled Cooling of Forgings - Potential Replacement to Normalizing and Iso-Annealing
Potential Replacement to Normalizing and Iso-annealing.
Udayan Pathak1, Vikas Shingade2
Tata Motors Limited, Pune, Maharashtra, India
Abstract
Forgings are often Normalized or Iso annealed to achieve consistent hardness in controlled hardness band and impart good Machinability. The controlled cooling rate after trimming can give the similar results as normalizing. The Microstructure obtained by controlled cooling is predominantly coarse grain and consists of pearlite plus ferrite matrix. Coarse grain structure results in improved machinability. The reduction in CO2 emission is possible to the tune of 250 Kg / ton forge weight. This needs specially designed tunnel to control cooling rate.
This paper will give details of properties achieved for a carburising grade of steel, refinement of steel specifications and process control required to replace normalizing / iso annealing by control cooling. The cycle & cooling rates established to achieve these results will be discussed.