MAG Welding - MAG Welding Conditions for High-Strength Steel (Except 1500 MPa) Parts
1. MAG Welding Conditions for High-Strength Steel (Except 1500 MPa) Parts

If a high-strength steel part (340MPa or higher) is MAG welded, the welding wire used must have a tensile strength equal to, or greater than, the lowest tensile strength of the parts being welded. The wire below, or equivalent, may be used for 980 MPa or less (except butt welding for 980 MPa, which is prohibited) high-strength steel welding.

Welding Wire (Example)

Must use 0.8 mm (0.031 in) diameter wire with a tensile strength of 980 MPa or higher (142 ksi or higher) .

Tensile strength of steel plate and welding method
Tensile
Strength
(MPa)
Welding Method
MAG Weld
Plug
Butt
340
?
?
440
?
?
590
?
?
780
?
?
980
?
×
1180
?*
×
1500
?*
×
*: MAG plug welding is only allowed on these steel grades in selected locations as specified in the body repair manual. Welding instructions must be followed exactly as specified to ensure adequate weld strength.

Be sure to check the product specifications issued by the manufacturers for details on welding wire.

Plug Weld:
Drill plug holes according to the sheet thickness referring to the table shown at left.
To determine the thickness of the parts being welded, refer to the “Body Construction” pages in the “General Information”section of the model specific body repair manual.

Plug hole diameter (reference)
Thickness
mm (in)
Less than
1.0 (0.039)
1.0-1.5
(0.039-0.059)
1.6-2.3
(0.063-0.091)
Hole
diameter
? mm (in)
6.0 (0.24)
8.0 (0.31)
10 (0.39)
Plug Welding:
Start welding 1.0 mm (0.039 in) from the outer circumference of the edge of the plug hole.
Weld upper and lower plates completely around the edge of the hole.
Perform a trial weld to confirm welded finish using test parts. Then perform the actual welding.
Butt Welding:
Perform a trial weld using the same welding conditions as the actual welding you will be doing. Confirm that the bead protrudes from the back side of the weld.
To ensure adequate weld strength, grind the test weld flat and then perform the welding so that the bead will protrude from the back side of the weld.