Stainless Steel Mechanical Properties

The stress-strain relationship provided by EN1993-1-2 for stainless steel at elevated temperatures is applicable for heating rates between 2 and 50 K/min. The detailed mathematical formulae are shown in Figure 1.

Table 1, Table 2, Table 3, Table 4, Table 5 give the reduction factors, relative to the appropriate value at 20°C, for the stress-strain relationship of several grades of stainless steel at elevated temperatures as follows:

Slope of linear elastic range, relative to slope at 20°C:	kE,θ = Ea,θ / Ea
Proof strength, relative to yield strength at 20°C:	k0.2p,θ = f0.2p,θ / fy
Tensile strength, relative to tensile strength at 20°C:	ku,θ = fu,θ / fu
Correction factor for yield strength:	k2%,θ
Slope over proof strength, relative to slope at 20°C:	kE,θ = Ea,θ / Ea
Ultimate strain:	εu , θ

The correction factor for the yield strength k_2%,θ is for the use of simple calculation methods. It is assumed that the “effective” yield strength to be used in simple calculation methods should be between the values of proof strength f_0.2p,θ and tensile strength f_u as given by:

(1)

where the values of k_2%,θ for various grades of stainless steel, ranging from 0.19 to 0.47, are given in Table 1 to Table 5, respectively.

Figures 2, Figure 3, Figure 4, Figure 5, and Figure 6 illustrate the variation of the above mentioned reduction factors for various grades of stainless steel. It can be seen that EN1993-1-2 assumes the same reduction rate for the slope of the linear elastic range k_E,θ for all steel grades.