This predictive method is base on the following paper.

N. Yurioka: Perdition of weld metal strength, IIW Doc. IX-2058-03

This method first predicts the weld metal hardness, Hv from weld metal chemical composition (C, Si, Mn, Cu, Ni, Cr, Mo, V, Nb, Ti[wt%]) and the welding cooling time (t85[s]).

Hv = (HM + HB)/2 - (HM-HB) arctan(x)/2.2

x = 4log(t85/tM) / log(tB/tM) - 2

HM = 884C + 294

tM(s) = exp(10.6CEI - 4.8)

CEI(wt%) = C + Si/24 + Mn/(2.88(1 +Mn)) + Ni/30 + Cr/16 + Mo/8

HB = 145 + 130 tanh(2.65CEII - 0.69)

CEII(wt%) = C + Si/24 + Mn/(2.16(1 + Mn)) + Cu/10 + Ni/45 + Cr/10 + Mo/5 +2V + 2.2Nb/(1 + 5Nb) + Ti/10

tB(s) = exp(6.2CEIII + 0.74)

CEIII(wt%) = C + Mn/(1.68(1 + Mn)) + Ni/15 + Cr/10 + Mo/8

Then, Hv thus obtained is converted to the weld metal tensile strength, TS.

TS(MPa) = 3.0Hv + 22.3