Fiat 500 Collision Awareness Manual page 44

44 COLLISION INFORMATION
Preparation
CAUTION: All NVH foam must be removed from the repair area of the vehicle, as material is flammable.
• Prior to making repairs with STRSW, weld coupons must be created for testing. The test joint must be an exact
duplicate of the original joint, including layering and adhesive application. The testing is required to ensure the repair
restores the vehicle to its originally produced condition using the minimum weld nugget requirement chart.
• To correctly identify the material being welded or tested, the technician must posses an accurate material thickness
gauge
• No "improvements" to the vehicle design are allowed as this could have a negative impact on the vehicle as a whole.
The repair should mirror what was used on the vehicle at the assembly plant.
• Note, the weld is affected by more than just the thickness or number of panels being welded, but also material coat­
ings. Zinc based anti­corrosion coatings (i.e., galvannealing, galvanizing), sealers, adhesives, and E­coat will affect
welder performance. Any sandwich type coatings will increase weld time (and current in some types of STRSW
welders) required to accomplish an acceptable weld nugget.
• When preparing an E­coated panel for STRSW the E­coat must be removed from both of the mating flanges within
25mm. (1in.) of any flange. Corrosion protection is required anytime you remove E­coat. A scuffing disc should be
used to remove the E­coat without damaging other sheet metal coatings
• If the panel originally had structural adhesives it should be reapplied prior to welding. The adhesive should have a
corrosion inhibitor and cover all bare metal.
• Prior to creating weld coupons and the final body repairs, all coatings and dirt/road debris must be removed.
Testing
• Weld coupons identical to the repair situation need to be made prior to performing any repair. These coupons must
be tested (peel test) to determine if the weld nugget meets the minimum size outlined above in the Minimum Weld
Nugget Requirement Chart. Keep in mind that different material coatings, coating thickness, material thickness, and
joint configurations have a direct impact on nugget size.
GMAW (Gas Metal Arc Welding or "MIG")
Applications
• Sheet metal repairs where STRSW is not available or practical, and truck frame repairs.
• The most common usage of GMAW on uncoated or galvanneal coated steel will utilize a 75% Argon ­ 25% CO2
shielding gas mix, and AWS specification ER70S6 wire. When welding galvanized material, Flux Core Arc Welding
(FCAW) using AWS specification E71T­GS wire should be used to avoid weld porosity from the zinc in the galvanizing.
Weld Process
COMPONENT PARTS
WELDING PROCESS
Material Type
Material Thickness
Range
ELECTRODE TYPE
(AWS SPEC. A5.18)
ELECTRODE SIZE
ELECTRODE MAKER
TRUCK FRAME
Zinc and Zinc Iron Alloy coated sheet steels
GAS METAL FLUX
CORED
ARC
ARC
(Note: 1)
High Strength and Structural Quality Steels which includes HSLA, Marten­
2 mm ­ 4 mm
AWS AWS
CLASS. CLASS.
ER70S­6 E71T­11
(Note 3)
0.035 0.045
Lincoln® Lincoln®
NR­211­MP
BODY SHELL EXTERIOR & UNDERBODY PANELS
GAS METAL MIG BRAZE
ARC
(Note: 2)
(Note: 1)
sitic, and Dual Phase materials
0.6 mm ­ 1.02 mm
AWS AWS
CLASS. CLASS.
ER70S­6 ERCuSi ­
A Silicon
Bronze
0.023 ­ 0.025 0.035
Lincoln®
2012 FF
GAS METAL FLUX
ARC CORED
ARC
(Note: 1)
>1.02 mm ­ 3.0 mm
AWS AWS
CLASS. CLASS.
ER70S­6 E71T­11
(Note 3)
0.035 0.045
Lincoln® Lincoln®
NR­211­MP