MATERIAL-TECHNOLOGICAL MODELLING OF CONTROLLED COOLING OF CLOSED DIE FORGINGS FROM FINISH FORGING TEMPERATURE

Mechanical properties of closed die forgings reflect their microstructure which is formed during the manufacturing process. There are a number of process factors at play which govern the final microstructural condition of the forged part. Besides the amount of working and the forging temperature, there is the post-forge cooling rate which has a decisive influence on the resulting microstructure. An important pre-requisite for dealing with these aspects is the definition of the input requirements and the boundary conditions. For instance, an input requirement may involve obtaining the desired microstructure within the entire forged part. Boundary conditions include the actual capabilities of the forge shop in terms of the control over the forged part's cooling. Hence, predicting the resulting properties of the forged part's material is a complex endeavour. In ordinary forge shops, there is no other way of finding these properties than by trial and error, which is rather demanding. It is time consuming and costly because a number of cooling routes must be tried in the plant. An alternative to this is material-technological modelling. It is a highly effective method of modelling the cooling of forgings without interfering with the production. By this means, the optimum manufacturing route can be found which, once implemented, delivers the desired microstructure of the forged part at minimized cost.