Oxy Fuel Gas Welding

Question 1

What is Oxy-Acetylene Welding?

Answer 1

A non-pressure welding process that joins materials using heat generated by the combustion of air and fuel gas (usually acetylene).

Question 2

What are the types of flames in Oxy-Fuel Gas Welding?

Answer 2

1. Neutral Flame
2. Oxidizing Flame
3. Carburizing Flame

Question 3

Describe Neutral Flame in Oxy-Fuel Gas Welding.

Answer 3

• Ratio: C2H2:O2 = 1:1
• No chemical change in the molten metal.
• Flame temperature: 3200°C.
• Used for welding mild steel, cast iron, stainless steel, copper, and aluminum.

Question 4

Describe Oxidizing Flame in Oxy-Fuel Gas Welding.

Answer 4

• Ratio: C2H2:O2 = 1:1.5
• Flame temperature: 3500°C (hotter than neutral flame).
• Creates a loud roar.
• Used for copper and zinc base metals, not suitable for steel.

Question 5

Describe Carburizing Flame (Reducing Flame) in Oxy-Fuel Gas Welding.

Answer 5

• Ratio: C2H2:O2 = 1.5:1
• Flame temperature: 3150°C.
• Used for applications requiring low heat like brazing, soldering, and flame hardening.
• Consists of three cones: outer, intermediate, and inner.

Question 6

What are other gases used in Oxy-Fuel Gas Welding?

Answer 6

• Methylacetylene-propadiene: low heat output, oxidizing flame.
• Hydrogen: colorless and not visible.
• Hydrocarbon-based gases: low heat output, oxidizing flame.
• Used for welding low-melting metals like lead and thin small parts.

Question 7

What are the advantages of Oxy-Fuel Gas Welding?

Answer 7

• Most versatile method of welding.
• Low rate of heat generation.
• Portable welding equipment.
• Narrow Heat-Affected Zone (HAZ).

Question 8

What are the disadvantages of Oxy-Fuel Gas Welding?

Answer 8

• Not efficient for heavy sections.
• Not all types of metals can be joined.
• Flux produces fumes.
• Safety concerns.
• Prolonged heating results in a large Heat-Affected Zone (HAZ).