Investigation of Thermophysical Properties of Three Barrel Steels

Abstract

In this paper, thermal diffusivity and heat capacity measurements were performed for three types of barrel steel, 38HMJ (1.8509), 30HN2MFA, and duplex (1.4462). Thermal diffusivity tests as a function of temperature were performed in the range of room temperature (RT) to 500 °C, and specific heat in the range of RT to 1000 °C. All tests were carried out using NETZSCH specialized measuring stands: LFA 467 light flash apparatus and DSC 404 F1 Pegasus differential scanning calorimeter. In the measurements of thermal diffusivity, the reference material Inconel 600 was used. This made it possible to determine thermal conductivity and specific heat as a function of the temperature of barrel steel. The results of specific heat tests of the 38HMJ and the 30HN2MFA steels show a ferrite–austenite phase transition in the 750–810 °C temperature range. This transition was not observed in the duplex steel.

Investigation of Thermophysical Properties of AW-2024-T3 Bare and Clad Aluminum Alloys

“…Subsequent heating and cooling processes did not differ from each other and also led to a linear relationship of thermal diffusivity as a function of temperature; this was the same for both alloys. Measurements of thermal diffusivity of bare and clad AW-2024-T3 alloys were performed simultaneously with measurements of thermal diffusivity of the reference material (POCO graphite), which allowed the temperature characteristics of specific heat and thermal conductivity for both tested alloys to be determined by the comparative method [ 38 ]. The results are illustrated in Figure 13 , Figure 14 and Figure 15 (cf.…”

Numerical Study of Heat Transfer in a Gun Barrel Made of Selected Steels

“…The maximum temperature limit of the barrel bore in operation is dictated by the thermophysical properties of the steel grade of the barrel. In the steel grades under consideration in our paper, a temperature above 800 • C causes allotropic changes connected with the reconstruction of the crystal lattice of the alloy [11,12]. The kinetics of change is well described by the dilatometric curve characteristics for the individual steel grades [11][12][13].…”

“…In the steel grades under consideration in our paper, a temperature above 800 • C causes allotropic changes connected with the reconstruction of the crystal lattice of the alloy [11,12]. The kinetics of change is well described by the dilatometric curve characteristics for the individual steel grades [11][12][13]. The effect of temperature on the barrel bore alters the volume of the surface layer, giving rise to a typical mesh of cracks.…”

“…Currently, this process is being replaced by nitriding. In any case, the protective coating is corroded by the structural transformations in the steel layer, which are directly related to the phase transition between ferrite and austenite [3,12,14]. At present, research is being conducted on the implementation of new steel grades with a higher allotropic transition temperature into the production of gun barrels [12].…”

“…In any case, the protective coating is corroded by the structural transformations in the steel layer, which are directly related to the phase transition between ferrite and austenite [3,12,14]. At present, research is being conducted on the implementation of new steel grades with a higher allotropic transition temperature into the production of gun barrels [12]. It is about shifting the ferrite-austenite phase transition towards a higher temperature or using steels in which this transition does not take place [11].…”