Grade
Marks and Material Properties for Bolts and Screws
Bolts,
screws,
and other fasteners are marked on the head with a symbol that
identifies the grade of the fastener. The grade specification
establishes the minimum mechanical properties that the fastener
must meet. Additionally, industrial fasteners must be stamped
with a registered head mark that identifies the manufacturer.
The grade identification table identifies the grade markings and
gives mechanical properties for some commonly used ASTM and SAE
steel fasteners. Metric fasteners are identified by property
grade marks, which are specified in ISO and SAE standards.
Grade Identification Marks and Mechanical Properties of Bolts
and Screws
Material Steel:
1—low or medium carbon; 2—medium carbon; 3—low carbon;
4—low-carbon
martensite; 5—weathering steel; 6—alloy steel; 7—
medium-carbon alloy.
Treatment:
a—cold
drawn; b—quench and temper.
