Standards for Screw-Grade Materials

That grades are according old DIN standards (DIN 267) or ISO 898, but they are just carbon steels defined by mechanical properties rather than chemical composition.

According to above mentioned standard, the first digit is the tensile strength expressed in N/mm² and divided by one hundred. Second digit express the yield strength as percentage of tensile and divided by ten.

Examples:

5.8 means a steel with a tensile strength of 500 N/mm² and a yield strength of 80% the tensile one, that is 400 N/mm² .

5.6 means TS ≥ 500 N/mm² and YS ≥ 300 N/mm²

8.8 means TS ≥ 800 N/mm² and YS ≥ 640 N/m

And so on...

Best regards

Would either of you know what current reference I can use to establish both mechanical and composition properties for screws? I am a civil engineer, and find myself off into, I think, the world of mechanical engineers. I have lost a lot of time on this question, and distributors are not very helpful.

Thank You, Paul

It depends on the specific requirements you have, country, etc.

Try to search on the different countries standards (as applicable). Bolting material properties are usually stated in relevant standards.

Try to google on "bolting manufacturers" Manufacturers use to give more technical information than distributors.

If you have any specific bolt/screw in mind just let me know.

Kind regards