Auto Collision - Welding

Welding

Using extreme heat to join or fuse pieces of metal together

MIG Welding

Metal Inert Gas Welding - allows welding for high-strength steel, high-strength low-alloy, in modern cars.

DC Reverse Polarity

The electrode wire is positive (+) and the workpiece is negative (-). The flow is always from negative to positive.

Plug Weld

Made in a drilled or punched hole through the outside piece(s). Arc is directed through hole to inside piece, then filled with molten metal.

Lap weld

Arc is directed to penetrate the bottom piece and puddle is allowed to flow into the edge of the top piece.

Lap joint

The structural arrangement where two pieces of material overlap

Shielding gas

Protects the molten weld pool from atmospheric contamination. Gases in the air, such as oxygen and nitrogen, can weaken a weld and cause defects like porosity.

Porosity

The formation of gas-filled cavities or voids within the solid weld metal, caused by gases like hydrogen, oxygen, or nitrogen being trapped as the molten weld pool solidifies. It can significantly weaken the weld, potentially leading to structural failure.

Nugget Hole

A void, or hole, in a weld caused by trapped gases, material expulsion, or incomplete fusion.

Nugget

The small, fused spot of metal formed between two or more joined workpieces.

Destructive Testing

Actually damaging a piece of welded metal to test its strength and quality. Done after a visual inspection. Destructive testing includes a twist test and a tensile shear test.

Backing piece

A piece of material placed at the root of a weld joint to support the molten weld metal, prevent burn-through, and allow complete joint penetration.

Butt joint

Two pieces of metal "butted" up against each other with a backing piece behind them.

Root Gap

The deliberate space left between the edges of two components to be joined, typically a butt joint with a V-groove.

Open Butt Joint

Two metals "butted" up against each other with an intentional gap.

Drive Rolls

Responsible for gripping and feeding the welding wire into the gun.

ER70S-6

ER = Electrode 70 = tensile strength (psi) S = Solid 6 = level of silicon/manganese versus other grades

Rocker Panel

A part of the vehicle's body under the doors, between the front and rear wheels. It strengthens the wheel's frame

Bottom Coupon

The metal piece that forms the base of a weld joint

Fillet Weld

Triangular cross-section that joins two metal pieces at a right angle.

Bird Nest

A tangled, coiled mess of wires inside the welding machine when the wire stops feeding correctly.

Travel Speed

The rate at which the welding torch or electrode moves along the workpiece.

Welding Work Clamp

Ground clamp: complete the electrical circuit. Mechanical clamp: secures workpieces, preventing movement.

Weld-through Primer

Zinc or copper-based coating applied to metal surfaces to protect from corrosion

Wire Transfer Modes

How molten metal moves from the electrode to the base metal (short-circuit, globular, spray, pulsed-spray)

Penetration

The depth to which the welding heat fuses the base metal.