Cooling time t8/5

per EN 1011-2, Annex D

Input

V
A
cm/min
mm
°C

Result

Cooling time
t8/5 = 18.16s
Arc energy
E = 2.31kJ/mm
Heat input
Q = 1.85kJ/mm
Transition thickness
22.36mm
Heat flow
two-dimensional
The value lies within 10 to 25 s, the range EN 1011-2 quotes as usual for filler and capping passes in unalloyed and low-alloy steels.

The plate is thinner than the transition thickness. Shape factor applied: 1.00.

Shape factor per EN 1011-2, Table D.1.

Adjust factors

Leave empty to use the table values. Custom values make sense for processes, arc types or welding positions the tables do not cover — but the result is then no longer covered by the standard.

table value 0.80
table value 1.00
table value 1.00
Background and formulae

The cooling time t8/5 is the time a weld run and its heat-affected zone take to cool from 800 °C to 500 °C. It largely governs the mechanical properties of the joint.

Q governs, not E

Arc energy E is the energy supplied per unit length; heat input Q the share of it that reaches the workpiece: Q = η · E. The cooling time is governed by Q. That is why the third input path needs no welding process — Q already contains the efficiency.

t8/5 = (6700 − 5 T0) · Q · [ 1/(500−T0) − 1/(800−T0) ] · F3
t8/5 = (4300 − 4,3 T0) · 105 · (Q/d)2 · [ (1/(500−T0))2 − (1/(800−T0))2 ] · F2

Limits of the method

  • The concept applies to joints of equal plate thickness. For unequal thicknesses it gives an indication only.
  • The cooling time is a window, not a lower limit: cooling too fast hardens the material, too slow costs toughness.
  • This calculation does not replace a welding procedure test.

Sources

  • EN 1011-2:2001+A1:2003, Annex D
  • EN 1011-1:2009, Table 1