The above statement is true. Substitutional alloy and interstitial alloys are types of alloys.

The above statement is false. The hardness number increase with increase in carbon content in steel as more martensite is formed with increase in carbon content.

Martensite is hardest and most brittle microstructure of steel. It has a higher hardness number than tempered martensite, fine pearlite and pearlite. Tempered martensite is harder than fine pearlite.

In a typical steel, carbon may contribute maximum of 2.14% of weight of alloy. Therefore only 2% lies within range and hence is correct answer.

Pure iron turns into its FCC structure at a temperature of 910 °C. This structure is called gamma iron or ?-iron.

The above statement is true. Annealing temperatures are low in stress relief annealing so that useful effects of cold working are not eliminated.

In a hardenability curve, which is made by keeping hardness number on y-axis and distance from a quenched end at x-axis. The hardness number decrease as distance from quenched end increases.

The above statement is true. In malleable cast iron, graphite turns into spheroidal particles rar than forming flakes.

Hydroforming is a type of forming in which a special die is used which uses high pressurized fluid to give shape to metals and metal alloys like steel, copper and brass.

The above statement is false. Shrinking is a process which is used to remove dents in which direct damage is not severely stretched.