Marking system for performance...

I. Marking System of Performance Level

The mechanical performance grade marks of bolts, screws and studs are expressed by two numbers separated by a dot (see Table 1-3 of ISO 898-1). The bits on the left of the dot or two digits represent one-hundred of the nominal tensile strength Rm NOM (see Table 3 of ISO 898-1, Line 1). The number on the right side of the point represents the stress Rp0.2.nom at nominal yield strength (lower yield strength) or 0.2% non-proportional elongation, or 0.0084d at specified non-proportional elongation, Rpm.nom (see ISO 898-1 table 3, line 2-4) and 10 times the ratio of nominal Hangzhou tensile strength Rm.nom, as shown in Table 2-3-2 (ISO 898-1 table 1) (yield strength ratio) 。

Standard Provisions: Fasteners (e.g. d > 39mm) that exceed the size range specified in this standard may also be marked according to this marking system when all materials and properties meet the requirements. The marking system also stipulates that the bearing capacity is reduced due to the shape of the head or the geometric size of the rod. "O" should be added before the grade mark to indicate the difference. If the grade mark of a fastener with nominal tensile strength Rm.nom=800 MPa and yield strength ratio of 0.8 is 8.8, the grade mark of the fastener with reduced load-bearing capacity made of the same material is 08.8.

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