Effect of different elements in medium manganese & 880 grade rails, Chemical composition of 880 grade rails

Effect of different elements in medium manganese & 880 grade rails.

Carbon

Carbon, from carbide Fe3 C is called (cementite). Steel is fully pearlitic, carbon contents are 0.8%. It may be noted that above 0.8% carbon increases hardness, yield point and ultimate tensile strength. Beyond this percentage, it also tends to make steel brittle.

Manganese:

It is used for deoxidizing the molten steel. It has greater affinity for oxygen than Iron. Above 0.8% manganese enables higher tensile strength and better harden ability.

Silicon:

Its presence is used as deoxidizing agent in the production of steel. Presence less than 0.1% in rimmed steels and 0.1% to 0.5% in killed steel does not affect the physical properties of steel to any useful degree.

Phosphorous:

Phosphorous is a harmful element in steel. It makes steel brittle and liable to crack when cold worked. Phosphorous is usually restricted to 0.03%, to increase tensile strength, hardness and yield point.

Sulphur:

It is also deleterious element, it makes steel liable to crack when hot. Sulphur content up to about 0.03% is generally allowed in steels.

The approximate proportion of various elements in different type of steels is as given in the Table.

chemical composition of rails


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