ALLOY STEEL

Steel which is produced with intended amount of one or more alloying elements in specified proportions to impart specific physical, mechanical, metallurgical and electrical properties.

Common alloying elements are manganese, silicon, nickel, lead, copper, chromium, tungsten, molybdenum, niobium, vanadium etc.

Some of the common examples of alloy steels are :

(a) STAINLESS STEEL: which essentially contains chromium (normally more than 10.5% with/without nickel or other alloying elements. As the name implies, stainless Steel resist staining/corrosion and maintains strength at high temperatures.

Used widely in Utensils, architectures and in Industrial applications viz automotive & food processing products as well as medical & health equipment.

Commonly used grades of stainless steels (SS) are :

TYPE 304: Chrome –Nickel Austenitic S S accounting for more than half of SS produced in the world. 18 :8 SS used for utensils are the most common example.
TYPE 316: Chrome –Nickel (Austenitic) SS containing 2-3% Molybdenum , intended for specific industrial use.
TYPE 410: Plain Chromium (Martensitic) S S with exeptional strength. It is a low cost, heat treatable grade suitable for non-corrosive applications.
TYPE 430: Plain Chrome (Ferritic) S S, offering general purpose corrosion resistance, often in decorative applications.
TYPE 201/202 ETC.: Low Nickel Austenitic S S containing 2-5% Nickel . Used as cheaper substitute of Type 304 grade for production of utensils.

(b) SILICON-ELECTRICAL STEEL: which usually contains 0.6 – 6% silicon and exhibit certain magnetic properties, which make it suitable for use in transformers, power generators, and electric motors. They are normally supplied in 2 categories :

i) CRGO: Cold Rolled Grain Oriented Silicon-electrical steel sheets/strips, normally recommended for use in transformers and generators.

ii) CRNO/ CRNGO: Cold Rolled Non-Grain Oriented Silicon-electrical steel sheets/strips, normally recommended for use in rotating machines such as electric motors.

(c) HIGH SPEED STEEL: Alloy steel containing tungsten, vanadium, chromium, cobalt and other metals. Depending upon composition, they are classified as Cobalt Grade abd Non-Cobalt Grade. Used for manufacture of cutting tools.