Consolidated Tech Man - Holo-Krome

MECHANICAL PROPERTIES AND APPLICATION DATA, METRIC PRODUCT
MECHANICAL REQUIREMENTS
MATERIALS
Holo-Krome Metric socket products are made from Alloy Steel, containing
one or more of the following alloying elements: chromium, nickel, molybdenum
or vanadium in sufficient quantity to assure that the specified
strength properties are met after oil quenching and tempering at an
appropriate tempering temperature. The requirements for Class 12.9 in
ASTM F-568 are applied, which is parallel to the ISO specification 898
Part I for strengths of fasteners.
HEAT TREATMENT PRACTICE
Holo-Krome Metric socket screw products are hardened and tempered in
atmospherically controlled furnaces and quenched in oil above the
specified minimum tempering temperature.
HEADING PRACTICE
Screws from M1.6 to M24 are normally Thermo-Forged ® to insure proper
grain flow and reduced internal stresses. Screws over M24 nominal size
are hot formed.
WARNING
It is very important that the users of Socket Products, particularly
Socket Head Cap Screws, be aware that the practice in Europe and
other metric areas, is not to restrict the manufacture of these
products to Property Class 12.9.
In the USA, and in inch module parts, it has been customary that the
socket head cap screw configuration is always made from alloy steel
and always to a high strength level, typically 180,000 psi. Metric
countries produce this same configuration in alloy steels in Class
10.9 as well, and in Class 8.8 from carbon steel. It is vitally important
that an assembly designed around Class 12.9 cap screws be put
together with such screws. Beware of lower strength screws being
substituted.
THREADING PRACTICE
Standard metric socket head cap screws up to M36 can be rolled at Holo-
Krome. For thread lengths longer than standard, or special thread pitches,
the threads may be rolled or cut. Set screw threads may be rolled, cut or
ground.
APPLICATION DATA
Standard Holo-Krome Metric alloy socket products are manufactured
from alloy steels designed to obtain the optimum performance characteristics
for each product.
Holo-Krome Metric socket screws are Thermo-Forged to insure optimum
grain flow without causing fractures, bursts or strain-hardening of the
parts. The forming process allows grain lines to flow through the part for
greater part strength and head integrity. Socket walls are smooth and flat
and the bottom of the socket does not have broaching chips that reduce
socket depth and create a possible starting point for corrosion. Dimensional
control is also easier to maintain.
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