INDUSTRIAL VALIDATION OF PROCESSING MAPS OF 316L STAINLESS-STEEL USING HOT-FORGING, ROLLING, AND EXTRUSION

The development of microstructure in 316L stainless steel during indus trial hot forming operations including press forging (strain rate of 0 . 15 s(-1)), rolling/extrusion (strain rate of 2-8 . 8 s(-1)), and ha mmer forging (strain rate of 100 s(-1)) at different temperatures in t he range 600-1200 degrees C was studied with a view to validating the predictions of the processing map. The results showed that good col re lation existed between the regimes indicated in the map and the produc t microstructures. The 316L stainless steel exhibited unstable flow in the form of flow localisation when hammer forged at temperatures abov e 900 degrees C, rolled below 1000 degrees C, or press forged below 90 0 degrees C. All these conditions must therefore be avoided in mechani cal processing of the material. Conversely, in order to obtain defect free microstructures, ideally the material should be rolled at tempera tures above 1100 degrees C, press forged at temperatures above 1000 de grees C, or hammer forged in the temperature range 600-900 degrees C. (C) 1996 The Institute of Materials.