Question

What structure is formed in the heat affected zone of a medium carbon steel weld due to rapid cooling?

• A. Pearlite
• B. Ferrite
• C. Martensite
• D. Austenite

Hint:

To prevent the formation of martensite and reduce brittleness, controlling the cooling rate during welding is crucial, especially for medium carbon steels.

Answer 1

The Correct Option is C

Martensite is formed in the heat-affected zone (HAZ) of medium carbon steel when the cooling rate is very rapid, such as during welding. The rapid cooling prevents the formation of pearlite and austenite, causing the material to undergo a phase transformation into martensite, which is a hard and brittle structure.