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08/2018
www.hilti.group
S-BT-ER, S-BT-EF
The S-BT-ER stainless studs are made from the duplex stainless steel type 1.4462, which
is equivalent to AISI 316 (A4) steel grade. This grade of stainless steel is classified in the
corrosion resistance class IV according to DIN EN 1993-1-4:2015, which makes the material
suitable for aggressive environments such as coastal and offshore applications.
The microstructures of duplex stainless steels consist of a mixture of austenite and ferrite
phases. Compared to the austenitic stainless steel grades, duplex stainless steels are
magnetic. The surface of the S-BT-ER stainless steel fasteners is zinc-coated (anti-friction
coating) in order to reduce the thread forming torque when the stud is screwed in into the
base material.
The coating of the carbon steel S-BT-EF fasteners consists of an electroplated Zn-alloy for
cathodic protection and a top coat for chemical resistance (Duplex-coating). The thickness
of the coating is 35 µm. This product is designed for use in corrosive categories C1, C2 and
C3 according the standard EN ISO 9223.
The conductivity disc of the S-BT-ER / -EF HC is made from copper alloy CuSn8 with
a tin-coating on the surface and a sealing ring on the bottom side. The copper alloy is
classified as largely insensitive to stress corrosion cracking and pitting corrosion. The
conductivity disc is designed for use in corrosion categories C1 - C5 according to EN ISO
9223. It is therefore suitable for use in aggressive environments like coastal and offshore
applications.
To prevent corrosion of the base material due to the drilling process the following base
material thickness tII has to be given.
Corrosion information
