type iii structural fasteners

NUCOR Fastener
TYPE III STRUCTURAL FASTENERS
TECHNICAL DATA SHEET
Nucor Type III Structural Fasteners
are made using a special chemistry, corrosion
resistant (weathering) steel. The steel has to meet
the chemistry requirements as specified in the
applicable ASTM standards such as A325, A490
or A563. Type III fasteners, nuts and washers
are commonly used in outdoor structures such as
bridges or stadiums, where the steel is exposed to
the outdoor environment. When weathering steel
is specified, such as ASTM A242, A588, or A709,
then Type III Structural Fastener Products are used
to complete the connections.
Structural Fasteners meeting the Type III requirements are made from alloy steel containing copper,
chromium, and nickel. As the surface of the steel corrodes, instead of forming coarse, flaky rust, the
Type III material forms a fine-textured oxide coating that tightly adheres to the base metal. This oxide
coating seals the surface of the base metal from further corrosion. The surface appears to be a uniform
fine grained, deep brownish-red rust color. The protection of this oxide coating works well in moderate
environments such as normal outdoor weather, but, if exposed to more concentrated corrosive conditions,
such as heavy industrial fumes, the oxide may not form sufficiently to protect the base metal. The weathering
steel should also not be used in applications where the fasteners will be subject to rapidly-flowing water
(which might disrupt the oxide layer) or where some discoloration around the fastener (from “bleeding”
of the reddish oxide) cannot be tolerated.
Structural Fastener Grades A325 Type III and A490 Type III; A563 Structural Nut Grades C3 and DH3;
F436 Washers made from weathering steel; and Twist-off Tension Control F1852 Type III and F2280 Type
III Assemblies, all have mechanical properties identical to their corresponding type 1 steel counterparts,
however, the grade marking requirements are different to distinguish Type III structural products. On
structural fasteners the grade identification (i.e., A325, A325TC, A490 or A490TC) is underlined to
identify the fastener as Type III material. DH3 Nuts must have “DH3” on one nut face, and C3 Nuts and
F436 Type III Structural Washers must have a “3” stamped on one face.
TDS-003A 2-15-08
Nucor Type III Structural Fasteners are 100% Made in the U.S.A. from American Steel. Our products
are all formed on precision high speed formers, utilizing in-process quality systems with full traceability
from raw material to each container of product we ship. Chemical and physical certifications are
provided with every shipment. Nucor Fastener is TS16949 and ISO9001 Registered and our laboratory
is A2LA Accredited.
head marks
ASTM A325-3
ASTM A490-3
ASTM A563 Gr C3
ASTM A563 Gr DH3
Nucor Black Kegs are really “Green”! With an Average Recycled Content of 99%, Nucor Fastener
products qualify for “Green Building” applications or LEED® rated projects. Just as you would expect
from Nucor, the largest recycler in North America. It’s our Nature!
Nucor Fastener has the equipment, quality, systems, expertise, sources, people and distributor network
to supply your Type III Fastener needs!
TODAY, THAT LITTLE “n” MEANS BIG THINGS!
This Technical Data Sheet is subject to change without prior notification.
PO Box 6100
| St. Joe, Indiana 46785 | ph: (800) 955-6826 or (260) 337-1726 | fax: (260) 337-1726 | www.nucor-fastener.com