Thermal analysis of a step-like test block in superduplex material
subjected to a solution annealing heat treatment and water quenched. Aim of the present work is to follow the thermal evolution of a step-like superduplex test block during the solution annealing heat treatment and the subsequent water quenching. Experimental phase has been coupled to a numerical simulation using the software Magmasoft®, in order to set the software on the basis of the result obtained by empirical tests. Once software has been calibrated it is possible to use to predict in a reliable way the behavior of the treated pieces realized in the same material. Time-temperature curves obtained by experimental analysis have been used to calibrate the software, thus obtaining a very good approximation between real and simulated values.
Obtained curves have been superimposed to CCT curves of A995 J93404 in order to evaluate the intersection of them with precipitation fields (sigma 1%, sigma 5%) on the basis of different cooling rates. A step-like test block has been cast in A995 J93404 SDSS. Test block is composed by 4 steps with increasing thicknesses (70, 140, 210, 280mm), and each step has been drilled up to mid-thickness in order to insert a 3mm Inconel coated K-type thermocouple to follow the thermal history of the
treated piece. At the end of the experimental phase, test block has been sectioned in 4 different parts, corresponding to each step, and samples for mechanical, corrosion, metallographic tests have been machined from mid thickness of each step. Tests carried out on each single thickness have to satisfy Norsok
requirements and the analysis of each metallographic sample have the aim to reveal the correspondence between evaluations obtained by the observation of CCT curves and the real presence of intermetallic phases.