Table 6.

Values of the parameters in the NIST stress-strain model for structural, fire-resistive (FR), quenched-and-tempered plate (Q&T), and bolt steels

Parameter	Structural	FR	Q&T	Bolt	Units
r1	7.514	9.782	10.143	4.697
r2	1.000	1.000	1.000	1.000
r3	588	625	589	456	°C
r4	676	1334	837	2040	°C
r5	0.090	0	0	0
k1	7.820	9.832	9.753
k2	540	616	809		°C
k3	1006	5651	959		MPa
k4	0.759	15.339	0.766
n	0.503	0.446	0.344
m0	0.0108
m1	7.308
m2	613				°C
m3	0.126
ε0′	8.333×10−5				s−1
E0	206.0				GPa
e1	3.768
e2	1.000
e3	639				°C
e4	1650				°C