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Welding processes, protocols and certification

A look at MAG, STRSW, weld bonding, MIG brazing, MIG aluminum and more for steel and aluminum
Wednesday, September 30, 2015 - 07:00
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Four-step trigger is a very important function when welding aluminum, and it does take some practice to get used to it, but once you do it will become easy. For the lower-end aluminum welders without four-step trigger, you will have to perform a tail-in/tail-out procedure. Tail-in/tail-out is where you begin your cold start on the panel and push into the joint to allow the heat to build up, and then at the end tail-out or off the joint and back on to the panel to allow the crater not to be on the joint. This procedure is not allowed by most of the OEMs. Another procedure to prevent cold starts/craters is to tack weld small pieces of the extra scrap aluminum to the flanges and start and finish you weld on those tabs. After your weld is complete, you can cut them off and dress the edges. 

Aluminum welding is difficult but not impossible to learn and master; practice is paramount.  Aluminum likes to be welded hot and fast, and many of the aluminum welds are long. Some weld flanges can be 300mm long (12 inches). Unlike steel, there is no skip welding allowed; it is start on one side, then weld to the end. Technique is extremely important. The better the machine the easier it will be for you to become a good welder. Technician skill, body position, hand position, gun angle, gun position and travel speed can all adversely affect the weld quality. Please keep in mind that the OEMs will require very specific machines and they can be very expensive. Aluminum MIG welders start on the low end around $3,500 up to $20,000 for the high-end welders. 

Welding certification

This word “certification” has become a real catch phrase lately in the collision repair field. Each OEM with a collision repair program is using this term for their program and for their welding. Let’s look at some of the facts, and you can draw your own conclusions. Many of the OEM collision repair programs require some I-CAR training as a starting point. Some OEMs have decided to have I-CAR assist in a development of a specific vehicle-training program, while others have their own facility and training program. Most of the European OEMs require vehicle specific hands-on training classes at their own training facilities, while many of the US OEMs just require I-CAR classroom-type training. All the OEM programs have certain fees attached to them, along with some specific equipment purchases, facility appearance and general insurance coverage.   

Many of the OEM programs require the repair facilities to obtain the I-CAR welding series to be accepted to their specific welding certification. A number of the US OEMs utilize I-CAR’s new welding certification program, which is where your technicians are tested at their facility with their equipment. All welding test samples are visually inspected and destructively tested and then measured for tear out with an I-CAR welding gauge, in a shop situation. The I-CAR test is a six to eight hour test and you know the results at the end of class. Recertification is required every five years. 

Most of the European OEMs require the I-CAR aluminum-welding test and then they require their specific test. Most of the European OEMs have adopted the ISO 9606-2 Welding Certification for their aluminum programs. The ISO 9606-2 test is generally a 40-hour test taken over a one-week period at the OEM’s training facility. Mercedes-Benz requires 80 hours taken over two weeks for the initial test. After performing multiple different weld configurations on cast and plate aluminum, all in the overhead position, the samples are sent to a lab for testing.  Some OEMs send only some samples to the lab, while other samples will be tested in-house by an ISO/AWS welding inspector. Recertification is every two years, except for Mercedes-Benz, which is every six months.

Fronius settings Fronius welder

 

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