Alloy Steels

ALLOY STEELS

1. What are Alloy Steels?

✓ In general terms, alloy steels mean any steels other than carbon steels.

✓ The Steels Products Manual defines alloy steels as steels that exceed one or more of the following limits:

Manganese - 1.65, Silicon -0.60%, Copper - 0.60%

✓ Also, a steel is considered to be an alloy steel if a definite amount or minimum of other alloying element is specified or required.

✓ Alloying elements: The most commonly used alloying ele- ments are chromium, nickel, molybdenum, vanadium, tungsten, cobalt, boron, copper, and others.\

2. Purpose of Alloying

The alloying of steel is generally done:

✔To increase its strength.

✔To improve hardness.

✔ To improve toughness.

✔ To improve resistance to abrasion and wear.

✔ To improve machinability.

✔ To improve ductility.

✔ To enhance grain size control.

✔ To achieve better electrical and magnetic properties.

3. Alloy Steels Vs Plain Carbon Steels

The advantages and disadvantages of the alloy steels in comparison with the plain carbon steels are presented in Table 3.3.

4. Classification of Alloy Steels

Alloy steels can be divided into two main groups as:

1. Low alloy steels: These contain upto 3 to 4% of alloying elements.

2. High alloy steels: These contain more than 5% of alloying elements.