ASME and ASTM grades

SME and ASTM grades are directly comparable and are often written A/SA 516 or SA/A 516
which is the same as A516 or SA516. ASTM (which is derived from the American Society
for Testing and Materials) and ASME (American Society of Mechanical Engineers) work
closely together and many of their standards are harmonised. For A 516 grade 60, which is one of most popular steels
For EN 10028 P indicates that it is a pressure grade steel. The number is the yield
strength when the plate is less than 16mm thick.
N indicates room temperature quality,
NH steels are for elevated temperature,
NL1 steels are of low temperature quality and NL2 steel – special low temperature
quality.
GH steels are for elevated temperature working.