## 1 Introduction
[14] proposed a non-destructive method to determine the effects of heat treatment of Usibor(r) 1500 steel, by measuring the thermal diffusivity of the material. The proposed thermographic procedure allowed, among other things, to determine the correlation between UTS and the thermal diffusivity of steel, achieving a commendable fit [15]. Single-point incremental forming (SPIF) is a less common sheet metal processing technology compared to conventional deep-drawing (CDD) processes [16]. Due to the long processing time, the use of SPIF is cost-effective in short-run production [17]. Despite this disadvantage, the technological advantage of SPIF is the ability to obtain much larger sheet deformations compared to CDD processes [18]. In SPIF, the rotational tool performs sliding movements according to a specified tool path strategy. The sheet is gradually deformed as a result of the interaction of biaxial tensile stresses [19]. Incremental sheet-forming (ISF) techniques are characterized by part-shape-independent tooling and higher process flexibility compared to CDD methods [20]. In SPIF, there are many parameters that determine the possibility of forming sheet metal, including tool rotational speed [21; 22], feed rate [18], vertical step size [21; 23], tool shape and dimensions [24], tool materials and coating [25], lubrication conditions [26], tool path strategy [27] and forming temperature [28]. In [29], the change in the structure and hardness of the AZ31 alloy was analysed, among others, depending on the temperature of the deformed material, which is a direct effect of the friction of the forming tool against the sheet metal surface. It was found that the increase in temperature in the material above 200 \({}^{\circ}\)C contributes to a decrease in the grain size and an increase in the hardness of the material after forming, in comparison to the base material. The 6000 series aluminium alloys were tested for the optimisation of the SPIF conditions. However, the testing of the EN AW-6082 grade is limited. [PERSON] et al. [30] investigated correlations among material formability and other mechanical properties (i.e., elongation, strain hardening coefficient, ultimate tensile stress) of the SPIFed EN AW-6114-T4 aluminium alloy. It was found that material formability in SPIF is most dependent on the percentage elongation and strain hardening coefficient. When forming EN AW-6451 aluminium alloy, [PERSON] and [PERSON] [31] found that the critical factors affecting SPIF are material thickness, drawpiece shape and incremental step size. [PERSON] et al. [32] investigated the effects of friction on forming load, surface finish and the formability of SPIFed EN AW-61111 aluminium alloy sheet when using the oblique roller ball tool. The advantages of the newly developed roller-based tool included higher formability and better surface finish of drawpieces compared to the SPIF with a rigid tool. [PERSON] et al. [33] proposed a pre-aged hardening SPIF process. Different wall angles during the process of EN AW-6061-T6 aluminium alloy were analysed to study forming limits. It was concluded that transformation strengthening contributes to a substantial increase in the hardness of the formed drawpiece. [PERSON] et al. [34] investigated the surface roughness of components formed by the SPIF process for the EN AW-6063 aluminium alloy. They found that the parameter that has the utmost effect on surface roughness is lubrication. [PERSON] et al. [35] investigated the effect of plunge depth, rotational speed and feed rate on the formability of EN AW-6061 alloy friction-stir-welded blanks. Analysis of joining material direction revealed that the blanks fabricated via diagonal direction had highest formability. [PERSON] et al. [36] investigated the effect of heat treatment on formability of EN AW-6061 aluminium alloy in SPIF. The considered approaches include solid solution/SPIF/ageing, solid solution/ageing/SPIF, and annealing/SPIF/solid solution/ageing.