Heat input


EN 1011-1 or CEN/TR 14599

Heat input, energy introduced into the weld region during welding per unit length.

AWS A3.0

Heat input. The energy applied to the workpiece during welding.
Heat input rate. The heat input per unit length of weld.

The heat input during welding can be viewed as a main influencing factor on the
properties of ferritic and ferritic-austenitic stainless steel welds in particular. This
influences the time/temperature cycle occurring during welding.


EN 1011-1 2009, Section 8.7


Thermal efficiency factor k are in accordance with Table 1 of EN 1011-1 : 2009.


ASME IX 2017


What is the difference between arc energy and heat input?

Arc energy is the energy supplied by the welding arc to the workpiece before the efficiency of the process is considered.

Code EN 1011 ASME IX
Heat input = arc energy x k arc energy
Refer to k factor, see Table 1 of EN 1011-1 see QW-409.1 a)

Essential variables (WPS)

BS EN ISO 15614-1 : 2017

ASME Section IX 2019


Equipement usage

Other tool as instructed in topic Inspection Tools for Welding Inspector


  1. Heat input calculator here.
  2. EN ISO standards: BSI Standards for welding inspector

ASME Heat Input Variables
Interpretation Number BPV IX-19-16