according to ISO 898, part 1

The mechanical properties are given for tests at room temperature.

Mechanical and physical properties of screws

a Values do not apply for structural bolting.
b For structural bolting d ≥ M12.
c Nominal values are specified only for the purpose of the desigation system for property classes. See clause 5.
d In cases where the lower yield strength ReL cannot be determined, it is permissible to measure the stress at 0,2% non-proportional elongation Rp0,2.
e For the property classes 4.8, 5.8 and 6.8 the values for Rpf min are under investigation. The present values are given for calculation of the proof stress ratio only. They are not test values.
f Proof loads are specified in tables F.006.
g Hardness determined at the end of a fastener shall be 250 HV, 238 HB or 99,5 HRB maximum.
h Surface hardness shall not be more than 30 Vickers points above the measured core hardness of the fastener when determination of both surface hardness and core hardness are carried out with HV 0,3.
i Any increase in hardness at the surface which indicates that the surface hardness exceeds 390 HV is not acceptable.
j Any increase in hardness at the surface which indicates that the surface hardness exceeds 435 HV is not acceptable.
k Values are determined at a test temperature of –20 °C.
l Applies to d ≥ 16 mm.
m Value for KV is under investigation.
n Instead of ISO 6157-1, ISO 6157-3 may apply by agreement between the manufacturer and the purchaser.

Download full chapter: Screws Property class 4.6 to 12.9/12.9
Login to download the document (PDF) 

For the purpose of providing services, this website uses cookies. You will consent to this by clicking on “OK” and/or using our services.
Please click on privacy policy to find the information on cookies and the possibilities for modifying the terms of their storage.