Arc Welding Techniques and Metal preparation

Objectives Understand Basic Welding techniques Understand the types of welds

Metal Preparation Free of dirt, grease, rust, paint, or other impurities Can Weaken the weld Clean by grinding, brushing, filing, or cutting

Welding Joints Butt, lap, tee, corner, and edge. Types of welds: fillet, groove, plug, slot, and surface

Tee weld is a type of fillet weld. The fillet weld has two surfaces at right angles, the bead is triangular in shape The groove weld A weld made in a groove between the two pieces of metal

Plug and Slot welds Used to join pieces that overlap. The welds are placed in plug or slot holes.

Surface Welds Beads deposited on a metal surface the purpose of building up the base metal.

Butt Joint

Single and Double V Butt Joint

Single Beveled Butt Joint

Lap Joints

Corner Joint

Edge Joint

Major Factors for Quality Welding 1. The proper amperage When correct, a sharp crackling sound can be heard. Too Low: Humming Too Loud: Popping

Major Factors for Quality Welding 2. the thickness of the base metal and the diameter of the electrode. 3. Arc Length equal to the diameter of the bare end of the electrode.

Major Factors for Quality Welding 4 Electrode Angle Hold the electrode at a 90 degree angle of the two plates being joined 5 to 15 degrees in the direction of travel.

Major Factors for Quality Welding 5. Speed of Travel It should produce a bead that is 1.5 to 2 times the diameter of the bare end of the electrode.

Welding Procedures Make sure safety is being followed Insert the electrode in the electrode holder and hold it about 1 inch above the metal Turn Welder on

Welding Procedures Lower the helmet, bring the electrode in contact with the work and withdraw it slightly. The metal and the electrode melt forming a metal pool called a crater

Welding Procedures 8. There are two methods used in starting the arc. striking like a match. tapping the electrode quickly on the surface to prevent it from sticking

Welding Procedures 9. Raise the tip of the electrode to about 3 /16 inch above the base metal. This forms a long arc which is held for a three count in order to preheat the base metal. 10. Lower the electrode to the correct arc length.

Welding Positions Vertical Horizontal

Welding Positions Flat Overhead