Civil Engineering - Building Materials - Discussion

Thank you @Ashok.

Excess silica makes the brick brittle and weak on burning.

Carbon causes the Brittleness then why answer is phosphorous? Anyone explain the exact answer.

Only carbon content is responsible for Ductility or brittleness of a material!

Phosphorus has no influence on mechanical properties.

DBT means ductile to brittle transition.

Phosphorus causes a DBT when the temp drops below some critical temp (which is known as cold brittleness or shortness because brittleness is caused due to lowering of temperature).

Sulphur causes a DBT when the temp rises above some critical temp (which is known as hot shortness because brittleness is caused at high temp).

Cold brittleness needs to be avoided because otherwise, steel will become brittle in winters.

Hot shortness doesn't affect much because steel will be brittle at a very high temperature and steel products will generally be at room temp.

Great, Thanks for sharing the information @Banpreet.

Excces of phosphorus then steel brittle at low temp. Is called COLD BRITTLENESS.

And; Excces of sulphur then steel brittle at high temp. Is called HOT BRITTLENESS.

Here Cold refer to cold steel.

Phosphorus additions can be used to strengthen sintered iron. But at contents above 0.6% P, the alloy becomes brittle.

Phosphorus increases hardness and brittleness, so given answer is correct guys.