Welding

Question 1

What is oxy-acetylene welding?

Answer 1

It is a non-pressure welding process that joins materials using heat from the combustion of air and fuel gas, specifically acetylene and oxygen.

Question 2

What are the three types of flames used in oxy-fuel gas welding?

Answer 2

Neutral flame, oxidizing flame, and carburizing (reducing) flame.

Question 3

What is the composition and application of a neutral flame in oxy-acetylene welding?

Answer 3

C₂H₂
₂ = 1:1, used for mild steel, cast iron, stainless steel, copper, aluminum, and their alloys.

Question 4

What are the characteristics of an oxidizing flame?

Answer 4

C₂H₂
₂ = 1:1.5, flame temperature is 3500°C, and it is used for copper and zinc-based metals. Not applicable for steel.

Question 5

What is the carburizing flame used for?

Answer 5

Suitable for applications requiring low heat, such as brazing, soldering, and flame hardening.

Question 6

What is the flame temperature of a carburizing flame, and what are its zones?

Answer 6

3150°C, consisting of an outer cone, intermediate zone, and inner cone.

Question 7

What gases are used in oxy-fuel gas welding other than acetylene?

Answer 7

Methylacetylene propadiene, hydrogen (not visible), and hydrocarbon-based gases.

Question 8

What are the advantages of oxy-acetylene welding?

Answer 8

It is versatile, portable, and generates a narrow heat-affected zone (HAZ).

Question 9

What are the disadvantages of oxy-acetylene welding?

Answer 9

It has a low heat generation rate, produces fumes due to flux, and prolonged heating results in a large HAZ.

Question 10

What energy source is used in arc welding?

Answer 10

Electrical energy.

Question 11

What is the temperature of an arc during arc welding?

Answer 11

About 30,000°C.

Question 12

What are the types of arc welding processes?

Answer 12

Consumable electrode processes and non-consumable electrode processes.

Question 13

Name some consumable electrode welding processes.

Answer 13

Shielded Metal-Arc Welding (SMAW), Submerged Arc Welding (SAW), Gas-Metal Arc Welding (MIG), Electrogas Welding, Electroslag Welding.

Question 14

What are some non-consumable electrode welding processes?

Answer 14

Gas Tungsten-Arc Welding (TIG), Atomic Hydrogen Welding, Plasma Arc Welding.

Question 15

What is Shielded Metal Arc Welding (SMAW) used for?

Answer 15

It is used in general construction, shipbuilding, pipelines, and maintenance, particularly in remote areas.

Question 16

What thickness of materials is SMAW best suited for?

Answer 16

3 mm to 19 mm, with multiple-pass welding.

Question 17

What types of joints are used in SMAW?

Answer 17

Lap, butt, corner, edge, and T-joints.

Question 18

Compare AC and DC welding in terms of power consumption.

Answer 18

AC welding consumes less power, while DC welding consumes more power.

Question 19

What is Submerged Arc Welding (SAW)?

Answer 19

A process in which the weld zone is submerged under a blanket of flux, using a consumable electrode and a high electric current.

Question 20

What are the advantages of Submerged Arc Welding (SAW)?

Answer 20

High deposition rates, deep weld penetration, minimal welding fume, no spatter, and high-speed welding of thin steels.

Question 21

What are the disadvantages of Submerged Arc Welding (SAW)?

Answer 21

It can only be performed on flat and horizontal positions, requires flux cleaning, and slag removal after welding.

Question 22

What are some applications of Submerged Arc Welding (SAW)?

Answer 22

Used for joining pressure vessels (e.g., boilers), earth-moving equipment, pipes, railroad construction, and shipbuilding.