API 653 Welding & Metallurgy

Question 1

What is the primary purpose of welding in metallurgy?

Accepted Answer

To bond metal parts by melting and fusing them together.

Answer

To strengthen the surface of metal parts.

Answer

To prevent rusting of metal parts.

Answer

To cool down the temperature of metals.

Question 2

What are the most common welding methods used in metallurgy?

Accepted Answer

Answer

TIG, MIG, Stick, and FCAW.

Answer

Laser and Plasma cutting.

Answer

Ultrasonic and friction welding.

Answer

Arc and heat welding.

Question 3

What is the difference between MIG and TIG welding?

Accepted Answer

MIG uses a wire electrode, and TIG uses a tungsten electrode for precision.

Answer

MIG uses a high-voltage arc, while TIG uses low voltage.

Answer

MIG is used for thin metals, and TIG is used for thick metals.

Answer

MIG is a manual process, while TIG is automatic.

Question 4

What factors affect the quality of a weld?

Accepted Answer

Heat input, speed, electrode type, and material cleanliness.

Answer

Only the electrode type.

Answer

Only the welding speed.

Answer

The size of the welding area.

Question 5

Why is preheat important in welding?

Accepted Answer

Preheating reduces the risk of cracking and improves fusion.

Answer

Preheating makes welding easier but is not crucial.

Answer

Preheating speeds up the welding process.

Answer

Preheating is used to clean the metal.

Question 6

What is the role of filler metal in welding?

Accepted Answer

To join metal parts by melting and bonding them together.

Answer

To increase the thickness of the base material.

Answer

To reduce the heat required for welding.

Answer

To prevent oxidation during welding.

Question 7

What is the importance of post-weld heat treatment (PWHT)?

Accepted Answer

It relieves residual stresses and improves mechanical properties.

Answer

It strengthens the base material.

Answer

It prevents the metal from rusting.

Answer

It is used only for aesthetic purposes.

Question 8

What are common defects in welding?

Accepted Answer

Cracks, undercutting, porosity, and incomplete fusion.

Answer

Only cracks and porosity.

Answer

Only surface appearance issues.

Answer

Only structural failures.

Question 9

How is the welding process selected for a specific material?

Accepted Answer

Based on material type, thickness, and joint design.

Answer

Based on the cost of the material.

Answer

Based on the size of the welding area.

Answer

Based on the material's color.