Quality classes for carriage bolts etc.

[Gaude]

Is there anyone who can tell me a little about quality grades for screws and bolts? I bought carriage bolts at Biltema with "quality grade 8.8", what does this mean?? I have also seen that they sell items with "strength class 4.6"???

Is this something that should be considered when purchasing these items?

 

[anaitis]

Is there anyone who can tell a little about the quality classes of screws and bolts? I bought carriage bolts at Biltema with "quality class 8.8", what does this mean?? I've also seen that they sell items with "strength class 4.6"???

Is this something that should be considered when purchasing these items?

With reservation for my memory (sitting in the countryside and have no ref nearby):
8.8 means strength 64 MPa
and
4.6 strength 24 MPa

i.e. 8.8 is better.

Whether it matters for your practical use??