[en] Highlights: • A new heat treatment technique was introduced for the physical simulation of materials processing using a stationary arc. • Steady state temperature distributions can be achieved and maintained, for different holding times. • The technique can be used to simulate conventional heat treatment, welding, multi-step heat treatments, and etc. • Arc heat treatment was successfully applied on a super duplex stainless steel and temperature distribution was modelled. • The alloy showed the formation of secondary phases and microstructure sensitization in the temperature range 850–950 °C. This paper introduces a novel arc heat treatment technique to produce samples with graded microstructures through the application of controlled temperature gradients. Steady state temperature distributions within the sample can be achieved and maintained, for times ranging from a few seconds to several hours. The technique reduces the number of samples needed to characterize the response of a material to thermal treatments, and can consequently be used as a physical simulator for materials processing. The technique is suitable for conventional heat treatment analogues, welding simulations, multi-step heat treatments, and heat treatments with controlled heating and cooling rates. To demonstrate this technique, a super duplex stainless steel was treated with a stationary TIG arc, to confirm the relationship between generated steady-state temperature fields, microstructure development, hardness, and sensitization to corrosion. Metallographic imaging and hardness mapping provided information about graded microstructures, confirming the formation of secondary phases and microstructure sensitization in the temperature range 850–950 °C. Modelling of temperature distributions and thermodynamic calculations of phase stabilities were used to simulate microstructure development and associated welding cycles.