The properties of thermal expansion, thermal conductivity and specific heat capacity of steel are dependent on steel temperature.

The coefficient of thermal elongation of steel Δl / l can be determined by:

(1)

where

l	is the length at 20°C;
Δl	is the temperature induced elongation;
θa	is the steel temperature [°C].

The variation of the thermal elongation with temperature is shown in Figure 1.

Figure 1 Thermal elongation of carbon steel as a function of temperature	Figure 2 Specific heat of carbon steel as a function of temperature

The specific heat of steel c_a [in J/kg•K] can be determined by:

(2)

The variation of the specific heat with temperature is shown in Figure 2.

The thermal conductivity of steel λa [in W/m•K] can be determined by:

(3)

The variation of the thermal conductivity with temperature is shown in Figure 3.

Figure 3 Thermal conductivity of carbon steel as a function of temperature