Extrusion limit diagram of IN 690 super-alloy tube based on hot processing map.

Extrusion limit diagram can be used to locate available deformation conditions for materials. The developed extrusion limit diagram of IN 690 (Inconel 690) tube was constructed through a new method by integrating analytic method, FE simulation and hot processing map. Extrusion force limit curve determined by the maximum extrusion pressure of the extruder, and temperature limit curve defined by the melting temperature of the material, which are two conventional curves for extrusion limit diagram, were obtained through FE simulations. Based on the hot processing map, high power dissipation efficiency limit curve calculated through analytical equations was firstly employed to construct the developed extrusion limit diagram. The overlap of reasonable regions bounded by these curves not only ensures smooth extrusion process, but also guarantees qualified products. Given that some special conditions were verified through FE simulations and one condition was validated through the on-site testing, the optimum region on the extrusion limit diagram is thus authentic and practical for the extrusion process of the IN 690 tube. [ABSTRACT FROM AUTHOR]