Fundamentals of Advances in special steels

Shamail Ahmad, NED University of Engg. & Tech. &

Peoples Steel Mills Ltd.

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Effect of Weight Percentage of Alloying Elements on Eutectoid Temperature

Effect of Weight Percentage of Alloying Elements on Eutectoid ‘C’ Content

Austenite and Ferrite Stabilizers

Effect of Weight Percentage of Alloying Elements on Expansion and Shrinkage of Authentic Region

Effect of Carbon %age on Martensite Temperature, Shape and Lattice Constant

Carbide Forming Elements

Structure of Metal Carbides

Hardness Comparison of Different Metal Carbides

Schaflar Diagram

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Each alloying element have a discrete effect in steel

These effects could be,

Solid Solution formation

Intermetallic Compound formation

Carbide formation

Stabilization of a particular Phases (ferrite, austenite, martensite)

Increase in Hardenability and Quenchability

Alteration of Eutectoid Transformation Temperature and Carbon Contents

Increase in Corrosion Resistance

Increase in Machinability

Increase in Mechanical Properties (in general)

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Hardness comparison of different

metallic carbides cont’d.

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“This diagram is used to predict the structure when

mixture of alloying elements are present in steels

by converting austenite and ferrite stabilizing

elements as Ni and Cr equivalent respectively”

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George Krauss, George Roberts and Richard

Kennedy, Tool Steels, 5th edn, ASM, 1998

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