Question

Manganese steel is used for making railways because.

• A. It is hard with high percentage of Mn
• B. It is soft with high percentage of Mn
• C. It is hard with small concentration of manganese with the impurities
• D. It is soft with small concentration of manganese with impurities

Answer 1

Answer: (A)

It is hard with high percentage of Mn

Steel is used to make rails for railway lines. This steel must be hard-wearing and resistant to cracking. This is achieved by careful choice of the composition of the steel and by carefully controlling the way the hot rail is cooled.

Before the development of heat treatment processes, the tensile strength and hardness of naturally cooled rails were controlled by the chemical composition of the steel.

Both of these properties of steel depend upon the proportion of carbon and manganese. It contains carbon up to a maximum of $0.82$%, and manganese a maximum of $1.7$ %, are needed to produce hard wear-resisting rails.

So, the correct option is $A$