“…The experimental material used in this study was API X80 high strength low alloy pipeline steel containing (wt.%): 0.058 C, 0.218 Si, 1.699 Mn, 0.007 P, 0.001 S, 0.226 Cr, 0.218 Ni, 0.247 Mo, 0.006 Cu, 0.029 Al, 0.073 Nb, 0.003 Ca, 0.014 Ti and Fe balanced. For low alloy steels with carbon content less than 0.6 wt.%, the calculation formula of austenite transformation temperature A c1 and A c3 is: 14) A ... (2) where ω refers to the percentage of the mass of elements. Through calculation, the values of A c1 and A c3 are 714°C and 869°C, respectively.…”