What is Grade A Steels? Grade A steel is a low & intermediate tensile strength hot Rolled steel in the form of plates for general Intermediate Strength applications. Grade A is a material grade and designation defined in ASTM A283 standard. ASTM A283 is an American material standard for hot Rolled steel plates for general intermediate strength usage.
Dimensional Characteristics of Grade A Steels: The applicable thickness for this Grade A material as defined in the ASTM A283 starts from 6 mm to 50 mm. The width is normally from 600 mm to 2000 mm.
The Chemical Composition of Grade A Steels: ASTM A283 defines the chemical composition of Grade A steels as under:
Maximum percentage of Carbon (C) is 0.14
Maximum percentage of Silicon (Si) is 0.4
Maximum percentage of Manganese (Mn) is 0.9
Maximum percentage of Phosphorous (P) is 0.035
Maximum percentage of Sulphur (S) is 0.040
Minimum percentage of Copper (Cu) is 0.20
Remaining is iron (Fe) percentage and with few negligible impurities.
Mechanical Properties of Grade A Steel: The tensile strength of the Grade A Steels is expressed in Newton per millimeters and it must be at-least 310 N/mm2 (MPa). The yield strength is minimum 165 N/mm2 (MPa). The minimum percentage ranges for elongation is 30%.
Grade A steel comparison with this grade of A36 material will show how it differs with higher strength steel in chemical composition & mechanical properties.