B.I.S Designation Systems For Steel

B.I.S SYSTEM FOR DESIGNATION OF STEEL

In the design of any machine, steel is an essential element. Steel is widely used almost everywhere, and machines are not an exception in it. As u know, there is various type of steel out there, and they have the different type of characteristics. So there is need to develop an accurate method to designate the different type of steel. B.I.S is used for this purpose.

Steels can be classified into two primary type. First one is plain carbon steel and the second one is alloy steel. Plain steel has only carbon and manganese content in it, but in the case of alloy steel there are other elements except for carbon like manganese,  silicon, nickel, sulfur, molybdenum, etc. also used. There are two different methods of designation for plain steel and alloy steel. Now let’s get started:

1)      A classification method for plain carbon steel:

a)      Multiply carbon content in steel by 100 and write it

b)      Write letter ‘ C .'

C)       Increase manganese content with 10 and write it.

For example, 64C8 means there is 0.64% of carbon and 0.8% of manganese in the steel. Characteristics of steel depend on the content of carbon and manganese.

2)      Designation method for alloy steel:

Let’s see and example, consider a steel which has following contents:   CARBON  0.12% to 0.18%  ;  SILICON 0.10% to 0.35% ; MANGANESE 0.40% to 0.60% ; CHROMIUM 0.50% to 0.80%.

Now for designation,

a)      Take the average of percentage content in steel.

B)      Multiply carbon content with 100 and write it first.

C)       If a percentage is less than on writing it with the underline following by the first letter of content. For example Cr65. If it is more than one, then there is no underline ( also multiply it with 100).

Here above steel can be written as    12Cr65 (manganese and silicon are not necessary, so that are deleted).

Þ      These designations are based on the percentage of an element in the steel, but there is also another type of name in which tensile strength of steel is used.

For example   FeE 250 means a steel with minimum yield strength of 250 N/mm² &  if u remove ‘E’ and just write Fe 360 that indicates a steel with the minimum tensile strength of 360 N/mm².