4
Specify Parker Grade
TM
- 6
Mo Tube
In any instrumentation application, one of the first steps to ensuring
safety and reliability is to select the right tubing for your process
Why selecting Steel 6Mo grade
over Steel 316 grade?
•
For all those applications
which involve moderate to high
chloride presence.
•
For those applications in which
316
has failed or is likely to fail
due to pitting, crevice or induced
stress corrosion cracking.
•
For those applications that
require compliance to NACE
standards and the existing 316
range can not meet such demand.
So important is the chemistry and
mechanical properties of the tube
when used in conjunction with Parker
A-LOK fittings, we have developed our
own Parker Grade
TM
6
Mo tubing. This
unique specification of tubing is optimal
in terms of hardness, ovality, chemistry,
and dimensional tolerances ensuring
ideal properties for the fitting.
Super austenitic stainless steel 6Mo
is a high performance alloy designed
specifically for added corrosion
resistance. It has the same structure
as the common austenitic alloys, and
greater levels of elements such as
chromium, nickel, molybdenum, copper,
and nitrogen, which gives it enhanced
strength and corrosion resistance.
6
Mo is especially suited for high-
chloride environments such as
brackish water, seawater, pulp mill
bleach plants, and other high-chloride
process streams. It is often used as
a replacement in critical components
where alloy 316/316L has failed by
pitting, crevice attack, or chloride
stress corrosion cracking. In many
applications, the super austenitic
stainless steels have been found to be
a technically suitable and much more
cost-effective alternative than nickel-base
alloys.
Typical applications of this
alloy are:
•
Seawater Handling Equipment
•
Pulp Mill Bleach Systems
•
Tall Oil Distillation Columns
and Equipment
•
Chemical Processing Equipment
•
Food Processing Equipment
•
Desalination Equipment
•
For NACE equipment in
processes over 60 °C, where 316
is not permitted.
Parker Hannifin carried out Stress
Corrosion Cracking Testing as
per ASTM G48 conducted by an
independent party that determined
the time to failure of 6Mo to be
3
times higher of that of 316. In
service applications, those results
translate into a life expectancy of
6
Mo three times longer than that of
316
in the same given conditions,
reducing leakage and downtime and
increasing safety by over 60%.
Why selecting Steel 6Mo grade
over Super duplex grades?
•
Choose 6Mo for improved
corrosion resistance and super
duplex for increased strength.
The higher strength of super
duplex grades can make
this material more susceptible
to stress corrosion cracking
under certain conditions.
Typical Composition
Element
Weight (%)
Carbon
0.02
max
Manganese
1.00
max
Chromium
19.5
to 20.5
Nickel
17.5
to 18.5
Molybdenum 6.0 to 6.5
Nitrogen
0.18
to 0.22
Copper
0.5
to 1.0
Typical Specifications
Product
Standard
Bar
ASTM A479
ASTM A276
Forging
ASTM A182 F44
Tube
ASTM A269
Other
NACE MR0175
NACE MR0103
UNS No.
S31254
•
For those applications that
are likely to suffer from pitting
corrosion. The pitting resistance
given by the PREN or Pitting
Resistance Equivalent Number is
higher for 6Mo than for its super
duplex counterparts.
•
Flue Gas Desulfurization
Scrubbers
•
Oil and Gas Production
Equipment