Fusion & Braze welding

When base metal and filler metal mix, what forms when cooled down?

Weld metal

What is the main difference between braze welding and fusion welding?

Fusion welding: base metal melts

Braze welding: base metal does not melt

What is an advantage of braze welding?

Low temperature less distortion

How is the oxy-fuel torch tip size determined?

Thickness of base metal

Which type of flame will result in brittle welds?

Oxidizing flame

What happens when the travel speed is too fast in oxy-fuel welding?

Lack of fusion, weak weld bead

What is a main consideration when choosing the welding tip size?

Thickness of base metal

What is a function of flux?

Removes and prevents oxides, proper bonding of filler metal

What should be consulted when setting up oxy-fuel equipment for operation?

Manufacturers instructions

Which adjustment is made to create and oxidizing flame from a neutral flame?

Increase oxygen

What is overlap in welding?

Excess of weld metal that expands over base metal without fusion

What is an acceptable weld bead profile in a fillet weld?

Smooth, slightly convex, proper fusion, correct leg size

Why is excess reinforcement undesirable in a groove weld?

Causes stress, weakens joints

Why is filler metal used when oxy-fuel welding?

Add strength, fill joint

Which filler rod is required when oxy-fuel welding on a base metal with a thickness of 4.8mm (3/16”)?

1/8” rod

Which metal is general purpose flux not suitable for?

Aluminum

What is a common problem in a corner joint if the fit up is too tight?

Lack of penetration

Types of joints?

Butt joint

Lap joint

T joint

Corner joint

Edge joint

What is done to a copper zinc electrode before using it to braze weld?

Heated and dipped in flux

Which welding position requires careful control to prevent weld pool from pulling away from edges?

Overhead

What is a 2F weld?

Horizontal fillet weld

What is tinning?

Applying a thin layer of molten metal to base metal

Why are the edges of the workpiece rounded when preparing to braze a single V groove weld?

better penetration

When pre cleaning grey cast iron prior to brace why is searing necessary?

Burn out oil and impurities so braze will bond properly

Which type of flame for silver alloy brazing?

Neutral flame