4300
Catalog
General Technical
T16
Parker Hannifin Corporation
Tube Fittings Division
Columbus, Ohio
http://www.parker.com/tfd
Media
Fluid Compatibility
The fluid compatibility chart on the following page is intended
as a guide only and is not to be considered as a sole selection
criteria to use Parker Tube Fittings in a specific application or
with a specific fluid. Other factors that must be considered
include, but are not limited to: Fluid temperature, ambient
temperature, system pressure (both operating and peak)
and applicable standards or regulations. For media not
listed, please contact your Parker representative or the
Tube Fittings Division.
Protective Coatings on Steel
P
rotective coatings such as electroplated zinc and cad-
mium1) and zinc phosphate are usually applied to steel
fittings for extending their useful service life in corrosive
environments. Cadmium and zinc corrode sacrificially,
protecting the steel substrate from normal atmospheric
rusting due to the common presence of oxygen, moisture
and acidic gases. They are, however, rapidly attacked
by many fluids including those containing acidic hydro-
gen and reactive fluorine, chlorine, bromine, iodine, and
nitrogen.
Zinc plating will further be attacked by strong
bases or water with pH > 12. Zinc reacts with gly-
col based fire resistant fluids and forms a gelatinous
compound that can plug up filters and be harmful
otherwise, in a system with many zinc plated tube and
hose fittings.
Steel fittings with zinc phosphate coating
or stainless steel fittings, along with brass fittings in low
pressure applications, are viable options.
Theother option is to run the fluid through the system, without
components with moving parts in it, with an auxiliary power
source, togenerate andflush the gelatinous compound. Then
re-connect all components, change filters and charge the
system with new fluid.
The corrosion resistance of the Chromium-6 Free standard
surface treatment is a minimum of 25% improved over
traditional zinc gold (hexavalent) chromate surface.
Additionally, the Chromium-6 Free surface meets the EU
end of life vehicle directive and ROHS compliance.
Zinc-Nickel (Parker XTR) plating offers enhanced
performance over both Chromium-6 Free (standard
treatment) and traditioal zincgold hexavalent chromate
surfaces. Parker XTR plating increases protection in salt
spray (ASTM B117) testing and in fertilizer (urea) applications.
Caution: Where low toxicity and low corro-
sion are required, as in food or beverage appli-
cations, steel coated with any form of zinc or
other protective coatings is not recommended.
Notes:
1)
Caution: Where low toxicity and low corrosion are
required as in food or beverage applications, steel
coated with any form of zinc or other protective
coatings is not recommended.
Choosing the Tube Material
and Type
Selection of tube material depends on the fluid, corrosive
nature of the service environment, the operating tempera-
ture range and the maximum operating pressure. The tube
O.D. and wall thickness selection depends on these four
parameters.
A simple method of selecting the proper tube type and
material is described below.
Table T16
lists several common tube types with their
recommended operating temperature ranges, general
application, and fitting compatibility. Based on the fluid
system parameters and media, select the appropriate tube
type and material.
If media and/or service environment is different from the
commonly used ones listed in the general application
column, please consult the Fluid Compatibility chart on the
following page or contact the Tube Fittings Division.
For selecting proper tube O.D. and wall thickness use the
procedure given on
pages T4
and
T28.
Caution: When working with highly corrosive media,
always consult the Tube Fittings Division.
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