Specifications of Structural and Heat Treatable Steels
(IS : 1977-1969; IS : 2062-1969; IS : 226-1969; IS : 961-1962)
Designation of steel Tensile strength kgf/mm Yield strength for thickness Elongation percent C
%		 S
%		 P
%		 Typical Applications
upto 20
mm		 20-40
mm
St 32-O 32-44 - - 26 - 0.07 0.07 General engineering purposes
St 42-O 42-54 26.0 - 23 - 0.07 0.07
 
St 42-S 42-54 26.0 24.0 23 0.25 0.055 0.055 All welded structures
 
St 42-W 42-54 26.0 24.0 23 0.20 0.055 0.055 Subjected to fusion welding
 
St 58-HT 58 Min. 36.0 35.0 20 0.27 0.055 0.055 Structures without welding
 
St 55-HTW 55 Min. 36.0 35.0 20 0.20 0.055 0.055 Structures with guaranteed weldability