Grade 660A vs. 660D nuts?

[fmdog44]

What is the difference between Grade 660A nuts and 660D nuts? We ordered D and got A.

 

[metengr]

http://www.stud-bolts.com/article_read_87.html#.VW4svs9Viko

 

[XL83NL]

hi metengr, the link provided doesnt show all details (at least on my pc), but I guess it proivdes diffferences in mechanical/chemical properpties.
apart from the mechanical/chemical differences between grade A and D, can you tell when to use one over the other? The same question would apply for other grades

 

[metengr]

XL83NL
It seemed the OP was looking for basic information for differences, which is why I provided minimum information. I doubt you will find specific information on materials selection/suitability other than minimum strength requirements and what you need for desired clamping load under various service conditions.