Mechanical testing of weld metal
Mechanical properties given in this catalogue refer
to typical values for test specimens taken from
all-weld metal material. They represent the average
obtained from a large number of tests, and for
established products they are based on the last five
years results from annual approvals check tests.
deformation and the yield strength is indicated with
the symbol Re and measured in units MPa.
Other weld metals e.g. stainless steel, do not show
the same well marked transition boundary and in
such cases the yield strength is defined as the point
when a specified permanent deformation remains
in the test specimen after the load is removed. The
catalogue values refer to a residual deformation of
0.2% and are designated Rp 0.2%.
Test plate preparation and specimen location for
all-weld metal testing is shown in the figure below.
Two types of test specimens are prepared – cylindrical test pieces for tensile testing and square Charpy
V-Notch test pieces for impact energy testing.
This is the maximum stress which the material under
test can be subjected to before fracture occurs and
is designated Rm.
The tensile test is used to determine:
• Tensile Strength
• Yield Strength
This is a measurement of the weld metal´s ability to
deform before fracture occurs. It is designated A5
and measured as a percentage of the original test
specimen length, which is normally five times the
The impact test is used to determine:
• Fracture toughness properties
Impact energy (fracture toughness)
Impact testing is used to determine weld metal
toughness at a given temperature, under impact
loading conditions, and is a measurement of the
material´s resistance to brittle fracture. Impact
energy is determined using a V-notch test specimen according to the Charpy-V method and is
measured in the unit joule (J). Fracture toughness
values are temperature dependant and decrease
with decreasing temperature. In general a weld
metal is “safe” against brittle fracture down to the
temperature which gives a minimum impact energy
value of 47 Joule.
The yield strength is the applied stress (load) at
which the material under test starts to yield plastically, producing a permanent deformation after the
load is removed.
Mild and carbon-manganese weld metals have a
clear transition point between elastic and plastic