The welding tests are usually performed as butt-welding with MAG-, MMA- or laser welding. The used filler materials are normally of different types and strength levels. Different heat inputs and number of passes are sometimes used. The welding parameters are carefully registered and documented.

The welding trials are submitted to visual- and non-destructive testing. Welded joints that do not fulfil the requirements in SS-EN-ISO 15614-1:2004 are not tested.

Mechanical testing
To evaluate the weldability specimens from the welding trials are submitted to mechanical testing. The mechanical testing is to a great extent performed in accordance with SS-EN-ISO 15614-1:2004.

Tensile testing
The tensile testing is conducted transverse to the welded joint. Testing is performed both with and without weld reinforcement. For more information about tensile testing click here.

Hardness testing
The method used to evaluate the hardness is Vickers. Indentations are made in the weld metal, HAZ and the parent metal for measuring and recording the range of values in the welded joint. The distance between the indentations is normally in the range of 0,3 - 0,5 mm. The measured maximum value for HAZ and weld metal is documented.

Steelfacts fusion welding

A Parent Metal
B Hardness indentations
C HAZ


Figure 1: Typical example of hardness testing 

Impact toughness testing
To evaluate the impact toughness of the welded joint the Charpy-V method is used. The specimen is machined transverse to the welded joint and the V-notch is cut perpendicular to the surface of the weld. Five different locations (A-D) in the weldment are tested, see figure 2. The different temperatures tested are in the range of 0 ºC to - 60 ºC. SSAB is normally testing impact toughness from a plate thickness of 6 mm. A reduced specimen is used for steels between 6 - 10 mm. The absorbed impact energy in the test is recalculated to J/cm2 due to the use of a specimen with reduced size, see example in figure 3.

Steelfacts fusion welding

a - centre of weld metal
b - fusion line
c - fusion line + 1 mm
d - fusion line + 3 mm
e - fusion line + 5 mm
1 Parent Metal
2 Weld
3 HAZ

Figure 2: Locations in the weldment where the notch is placed

Example

Steelfacts fusion welding

A Reduced size

If the read value on the impact toughness machine is 80 J, the recalculated impact energy for the reduced size specimen to J/cm2 is:

   (100/(5 x 8)) * 80 = 200

Answer: 200 J/cm2

Figure 3: Recalculation of impact energy (J) to J/cm2