Characterisation of EN 1.4136 stainless steel heat-treated in solar furnace

The paper presents a study concerning the characterisation of EN 1.4136 stainless steel heat-treated by means of concentrated solar energy in orde to improve some mechanical properties. In addition to the standard chemical composition, this steel was alloyed with nickel (Ni 1.5%wt) and copper (Cu 0.30%wt). Nickel was added to increase corrosion strength in acids, oxidising or non-oxidising environments, also facilitating an improved tenacity of the material. The addition of copper allows an increasing atmospheric corrosion strength (for copper content over 0.20%), at the same time intensifying the austenitising effect of nickel. The obtained steel was subjected to a solution heat treatment (hyper-hardening) with a heating time up to a austenitisation temperature (TA = 1050 °C) for 20 (lot A) and for 33 min (lot B), respectively. The maintaining duration for austenitisation was 7 (lot A) and 21 min (lot B), respectively, followed by cooling in water. After the heat treatment in the solar furnace, the specimens were analysed from the structural point of view as well as to their behaviour when subjected to tribological stress, in accordance with the operational requirements for these types of steels. The analysed characteristics were the dynamic friction coefficient (CoF), the wear rates and the hardness (HRC) tests. Based on the collected data, a specific characterisation was made for EN 1.4136 stainless steel heat-treated in a solar furnace. By applying the thermal treatments in the solar furnace, the hardness values have been increased (of about 55%) and the average wear rates have decreased compared to the base material.