GMW3359达克罗标准.pdf

WORLDWIDE
ENGINEERING Material Specification
GMW3359
Finish
STANDARDS
Non-electrolytically Applied Zinc Rich Coating
2 References
1 Scope
Note: Only the latest approved standards are ap
This specification covers the basic requirements
plicable unless otherwise specified
for a corrosion resistant non-electrolyticailly applied
zinc rich coating. Besides corrosion protection the
2.1 External Standards/Specifications
coating also provides color identification and lubri-
DIN 946
SAE/USCAR-5
cation by using an additional topcoat with inte-
I$0 1463
SAE/USCAR-11
grated lubricant such as wax or PTFE
ISO 9227
VDA621-415
1.1 Material Description. The material to this
ISO11014-1
specification covers organic or inorganic zinc fla
2.2 GM Standards/Specifications
coating with and without organic topcoat. This
coating system must be free of hexavalent chro
9981228
GM9509P
mium, with no hexavalent chromium in final prod
9984094
GM9540P
uct per GMW3059 requirements. GMW3034 will be
9985670
GME00255
used as a referee test. This coating process does
GM4465P
GMW3001
not generate hydrogen, however, pretreatment GM7114M
GMW3034
processes i.e. acid pickling could cause hydrogen
adsor ption. Non-electrolytically applied zinc rich
GM9071P
GMW3059
coating has high permeability, which allows ef
GM9501P
sion of hydrogen during curing which might have
been absorbed during acid pickling
3 Requirements
1.2 Typical Application. This coating is suitable
3.1 Appearance. The coating shall have a uniform
for extemally and internally threaded parts (size
appearance and shall be free from tears, sags,
greater than or equal to M6) and non-threaded
pores, cracks, flakes, blisters, rough spots, un
ferrous parts where high level of corrosion protec
coated areas and excess coating which affects
tion and freedom from hydrogen embrittlement are
appearance and performance. The coating shall
required. This is not recommended for the follow
not be oily or tacky to the touch. During normal
Ing
handling practice parts shall not leave particulate
a. Bolts and nuts of sizes< M6
residue on equipment, hands, or gloves. The coat
ng shall be completely cured and shall have ge
b, Parts with internal drive recess
to base metal. The color unless other-
wise specified shall be silver
C. Against magnesium surfaces
3.2 Thickness. When applied to threaded prod-
d. Washers of all sizes
ucts, the coating shall not have an adverse effect
e. Parts where electrical conductivity is required
on normal installation and removal practices. At
all be adequate
1.3 Remarks. Use of this coating system on
the same time coating thick
threaded surface and/or bearing surface of joints
to provide corrosion resistance performance re-
could effect the torque-tension relationship. It Is
quirements
recommended that a torque-tension study of the
3.2.1 The maximum thickness of coating whi
fastener joint be performed before releasing this
may be applied to threads on threaded products is
finish on any new application
imited by the basic thread size (tolerance h or H)
After coating,