CONV value is usually the film coefficient, and value 2 (below) is usually the overall temperature. If VALUE = -N, the film coefficient may be a function of temperature, which is determined by the HF characteristic table of material N [MP]. The temperature used to evaluate the membrane coefficient is usually the average value between body temperature and wall temperature, but for some elements, it can be defined by the user. l

The above is the content of abaqus help document. Personally, it means

(1)hf is the Convection or modulus coefficient of the material, and the value of conv is generally the value of the membrane (or convection) coefficient. If the value is -n, the HF value of the material is selected, which means that the original text is helpful. To put it bluntly, the value of CONV can be the convection or modulus coefficient of the material, or it can be other values.

(2) Theoretically; These two values are usually related; That is; Hf should be equal to conv；; But there are exceptions; At this time; There may be differences between them; Therefore; Two quantitative definitions are set to make the program more flexible;

I didn't simulate overheating convection. You can look for it in the simulation forum.