It’s tough down there.
Aluminized Steel Type 2
Corrugated Steel PipE
Aluminized Steel Type 2 Pipe for added durability
Strength of steel,
corrosion resistance of aluminum
Corrugated Steel Pipe (CSP) manufactured
from Aluminized Steel Type 2 offers
the corrosion resistance and surface
characteristics of aluminum with the
strength and value of steel.
The product is fabricated from steel coils
that have been hot dip coated in a bath of
commercially pure aluminum. The coating
has uniform thickness on both sides of
the sheet, with a strong metallurgical
bond between the metals. The Aluminized
Steel Type 2 material meets AASHTO
specifications M274 and ASTM A929.
The coils are then fabricated into helically
corrugated pipe meeting the requirements
of AASHTO specifications M36 and ASTM
A760. Helically corrugated steel pipe
has been a standard of the construction
industry for decades. Pipe is fabricated
with lock seams or welded seams
depending on the job requirements, and
each pipe end can be reformed to provide
at least two annular re-corrugations.
Excellent barrier protection
Aluminum forms a passive oxide layer that
adds to the service life by providing good
barrier protection. This passive oxide forms
rapidly and maintains better protection
over a wider environmental range than zinc
reaction products. The aluminum oxide is
stable in both hard and soft water.
The passive oxide will endure as long
as the free aluminum coating layer is
present. When this layer is eventually
penetrated, there is an underlying hard,
thick aluminum-iron alloy layer that
provides further corrosion protection plus
abrasion protection.
2
Pure Aluminum Coating
Steel Strip
Protective
Atmosphere
Alloy Layer
Commercially
pure Molten
Aluminum
Steel Base Metal
The photomicrograph on the left shows how the thick alloy layer metallurgically bonds the aluminum
coating to the steel base metal, as well as how the coating provides continuous protection to the base
metal. The same coating protection is provided to both sides of the steel base metal.
Based on field studies of 42 – 50 year
installations, Aluminized Steel Type 2
service life is estimated to be 75 years
minimum at 16 gauge in the 5 – 9 pH
and ≥ 1,500 ohm•cm resistivity ranges,
and 100 years in the same pH range and
resistivity ranges > 5,000 ohm•cm. For a
narrower pH range of 6 – 8, culvert data
supports 100 year estimated service life
for resistivities ≥ 1,500 ohm•cm.
In some cases, the pH/resistivity ranges
may be extended somewhat as is the
case in arid regions where moisture
availability is generally a controlling
factor, and satisfactory service life may
be realized at soil resistivities somewhat
below the 1,500 ohm•cm lower limit.
In wetter climates, satisfactory service
life may be realized at soil pH values
slightly below the 5.0 lower limit when
resistivities are relatively high.
In general, however, environments
outside the recommended pH/resistivity
ranges should be subjected to additional
testing to see if conditions conducive to
accelerated corrosion actually exist. For
example, low resistivity waters and soils
may contain excessive concentrations of
corrosive chloride and sulfates salts. In
addition, any dark or light gray, blue, or
olive colored clay constituents observed
in a heterogeneous soil should be
isolated for pH measurement since these
sometimes contain watersoluble heavy
metal salts. These constituents induce
strong acidification necessitating the use
of a bituminous coating to ensure normal
soilside corrosion behavior, or imported
compliant backfill.
Environments that are far outside the
recommended pH/resistivity ranges should
be avoided, including acid minewater,
seawater, estuary brackish water, and
sanitary/industrial sewage.
Standard specifications
1. AASHTO M274 (Aluminized Steel
Type 2 material) and ASTM A929
2. AASHTO M36 and ASTM A760
(conduit, pipe)
3. AASHTO Standard Bridge Design
Specifications, Section 12 (structural
design) and ASTM A796
4. ASTM A798 (installation)
Aluminized Steel Type 2
75 years minimum service life. And still counting.
75 75
years
minimum service life. And still counting.
years minimum service life And still counting
• The condition of Aluminized
Steel Type 2 pipe inverts—
a critical
point
durability
• The
condition
of in
Aluminized
design—was
excellent.
Steel
Type 2 pipe
inverts—
1952
–
53,
an
additional
135 composite
• InThe
condition
of
Aluminized
a critical
point inandurability
In 1952–53,
additional
135
culverts
of
Aluminized
Steel
Type 2 and
Steel
Type
2
pipe
inverts—
design—was
excellent.
composite culverts of Aluminized
galvanized
steel
were
installed in 20
a critical
point
ingalvanized
durability
Steel
Type
2
and
steel
In
1952–53,
an
additional
135
states. Based on the current conditions
design—was
excellent.
were
installed
in 20
states.
Based
of the pipes
available,
data indicates
composite
culverts
ofthe
Aluminized
on
the
current
conditions
of
the
a minimum
service
life steel
for
In Type
1952–53,
an
additional
135
Steel
2100
andyear
galvanized
pipes
available,
the
data
indicates
16
gauge
Aluminized
Steel
Type
2
pipe
composite
culverts
Aluminized
were installed
in 20ofstates.
Based
a
minimum
75-year
service
life for
when
installed
in
the
recommended
Steel
Type
2
and
galvanized
steel
on the current conditions of the
16
gage
Aluminized
Steel
Type 2
environment,
pHin5the
– 9data
with
resistivities
were
installed
20
states.
Based
pipes
available,
indicates
•
≥
5,000
ohm
cm
or
pH
6
–
8
with
installed
in the
on
the when
current
conditions
of recomthe
a pipe
minimum
75-year
service
life for
•cm.
resistivities
≥
1,500
ohm
mended
environment.
pipes
available,
the data
16 gage
Aluminized
Steelindicates
Type 2
a
minimum
75-yearin
service
life for
pipe
when installed
the recomIndependent studies
Independent
studies
16
gage environment.
Aluminized
Steel Type 2
mended
Many
independent
have
pipe
when
installed
instudies
the
Independent
studies have
beenrecomperformed
been
performed
that
confirm
Independent
studies
mended
environment.
that confirm
AK Steel
Corporation’s longAK
Steel
Corporation’s
term field
test.
Many
independent
studieslong-term
have
field
test.
Independent
studies
Coatings
for Corrugated
Steelconfirm
Pipe; R. M. Pyskadlo
been
performed
that
and J. P. Ewing (NYDOT); FWHA-NY-SR-87-90
Many
independent
studies
have
AK
Steel
Corporation’s
Durability
Analysis
of Aluminizedlong-term
Type 2 CMP; J. P.
been
performed
thatFWHA-RD-97-140
confirm
field
test.
Ault and
J. A. Ellor (OCR);
AK This
SteelAluminized
Corporation’s long-term
Steel Type 2
fieldcorrugated
test.
steel
�
pipe
was installed
This Aluminized
19532 in
Steel
Type
ThisinAluminized
ElSteel
Dorado,
corrugated
steel
Type 2
This Aluminized
California.
It steel
was
pipe
was
installed
corrugated
Steel Type 2
inspected
in 1982
in 1953
in in
pipe was
installed
corrugated steel
and
in
1995.
El in
Dorado,
1953
El Dorado,
pipe was installed
Coupons
California.
It was
California.
Itwere
was
in 1953 in
removed
1995
inspected
in in
1982
inspected
in
El Dorado,
forand
evaluation
by
1982,1995
in 1995.and
California. It was
the AK
Steel
in 2005.
Coupons
Coupons
were
inspected in 1982
werein
removed
in
Research
Center
removed
1995
andfor
in evaluation
1995.
1995
CALTRANS.
forand
evaluation
by
Coupons
were
by AK
the AK
Steel
the
Steel
removed
in
1995
Research
Center
Research
Center
for evaluation
by
and CALTRANS.
and CALTRANS.
the AK Steel
Research Center
and CALTRANS.
�
This close-up view shows the Aluminized
Steel Type 2 pipe installed in Garland,
�Maine, with the dark staining wiped away
to close-up
reveal theview
like-new
aluminum.
This
showsunderlying
the Aluminized
Steel Type 2 pipe installed in Garland,
� This close-up view shows the Aluminized
Maine, with the dark staining wiped away
This Steel
close-up
Aluminized
Type 2view
pipe shows
installedthe
in Garland,
Maine,
to reveal the like-new underlying aluminum.
the2dark
staining
wipedinaway
to reveal
Steelwith
Type
pipe
installed
Garland,
the like-new
aluminum
Maine,
with theunderlying
dark staining
wiped away
to reveal the like-new underlying aluminum.
�
�
AK Steel Research
Center’s corrosion
engineers and
AK
Steel
Research
D.O.T.
AKMissouri
Steel
Research
Center’s
corrosion
material
engineers
Center’s corrosion
engineers and
inspect
aand
43-year
engineers
Missouri
DOT
AK Steel
Research
old
Aluminized
Missouri
D.O.T.
material
engineers
Center’s
corrosion
Steela Type
2 pipe
material
inspect
43engineers
year
engineers
andold
installation.
This is
inspect
a Steel
43-year
Aluminized
Type
Missouri D.O.T.
one
of two culvert
Aluminized
2old
pipe
installation.
material engineers
installations
in
This
is one
Steel
Typeof 2twopipe
inspect
a 43-year
culvert
installations
Carter
County,
installation.
This is
Aluminized
inold
Carter
County,
Missouri,
installed
one
of two
culvert
Steel Type
2 pipe
Missouri,
installed
in
in a series
containinstallations
in
This is
ainstallation.
series
containing
ing half
Aluminized
Carter
County,
oneAluminized
of two culvert
half
Steel
Steel Type
2 pipe
Missouri,
installed
Type
2 pipe andinhalf
installations
and
half
galvanized
in
a
series
containgalvanized
steel pipe.
Carter County,
ingsteel
halfpipe.
Aluminized
Missouri, installed
Steel Type 2 pipe
3
in a series containand half galvanized
ing half Aluminized
steel pipe.
Steel Type 2 pipe
and half galvanized
steel pipe.
�
�
�
normal drainage project. Aluminized Steel Type 2 pipe offers a
durable
and economical
alternate
normal
drainage
project. Alumito reinforced
concrete
nized
Steel Type
2 pipe pipe.
offers Feaa
tures
include
light
weight,
long
normal
drainage
project.
Alumidurable and economical alternate
Ideal
for
storm
sewers
and
joints
that
have
nized
Steel
Type
2 pipe
offers
a
tolengths,
reinforced
concrete
pipe.
Feapositive
pull-apart
resistance
durable
and
economical
alternate
tures include light weight, long and
Aluminized
Steel
Typeto
2 corrugated
the
ability
adjust
yielding
to
reinforced
concrete
Fea-steel
lengths,
andtojoints
thatpipe.
have
pipe
is
an
ideal
material
for
municipal
foundations.
tures
include
light weight,
long
positive
pull-apart
resistance
and
storm
sewers
or any
normal
drainage
Pipeand
and
pipe-arch
are
lengths,
joints
that
have
the project.
ability
to
adjust
to
yielding
Aluminized
Steel Type 2 pipe offers
available
in four resistance
corrugations
positive
pull-apart
and to
foundations.
a 2durable1and economical alternative
/3"and
x to/adjust
2", 3" x 1", 125mm x
(2Pipe
the
ability
to
yielding
pipe-arch
are
reinforced concrete pipe. Features
include
25mm, and
Spiral
Rib’s 3/4" x
foundations.
available
in
four
corrugations
light
weight,
long
lengths,
and
joints
that
3
1
/
4" x 71 /2" rib corrugation) and
2Pipe
and
pipe-arch
are
/3" xpositive
/2", 3"
x 1", resistance
125mm xand the
(2 have
pull-apart
inability
all standard
available
four
corrugations
toinadjust
todiameters
yielding
/4and
"x
25mm,
and
Spiral
Rib’s 3foundations.
2
1
16
gage
10
gage.
3
1 /through
/
3
"
x
2
",
3"
x
1",
125mm
x
(2
/4" x 7 /2" rib corrugation) and
3
Long-term
field
testing
/and
4" x
25mm,
and Spiral
Rib’s
in
all
standard
diameters
field
testing
3 Long-term
1
/4"gage
x 7 /through
2" rib corrugation)
16
10 gage. and
Based
on extensive
data
from
actual
on
extensive
data
from
inBased
all
standard
diameters
and
field
installations
dating
back
50
actual
installations
datingyears,
Long-term
field
testing
16
gagefield
through
10
gage.
Aluminized
Steel Aluminized
Type 2 is a superior
back
43extensive
years,
Steel
Based
on
dataand
from
product
for
storm
sewer
drainage
Type
2
is
a
superior
product
for
Long-term
field
testing
actual
fieldItinstallations
datingresistance
projects.
has better corrosion
storm
sewer
and
drainage
projects.
Based
on
extensive
data from
back
43
years,
Aluminized
Steel
than
galvanized
structures
and
displays
It
has
better
corrosion
resistance
actual
dating
Type
2field
isabrasion
a installations
superior
product
for
better
resistance.
than43
galvanized
structuresprojects.
and
back
years,
Steel
storm
sewer
andAluminized
drainage
abrasion
resistance.
Type
2better
is 1953,
abetter
superior
product
for 2
Prior
to
Aluminized
Steel
Type
It displays
has
corrosion
resistance
Prior
to
1953,
Aluminized
galvanized
culvertsand
wereSteel
storm
sewer
andsteel
drainage
projects.
thanand
galvanized
structures
Type
2 better
and
galvanized
steel
exposed
incorrosion
sites
acrossresistance
the
U.S. These
Itdisplays
has
better
abrasion
resistance.
culverts
were
exposed
in
sites
sites
represented
a
variety
of
service
thanPrior
galvanized
and
to 1953,structures
Aluminized
Steel
across
the
U.S.
These
sites
repreconditions
including
farm
field
drainage,
displays
better
abrasionsteel
resistance.
Type 2 and
galvanized
fresh
water
swamps,
alkali
soils,
and
sented
a
of
service
condiPriorwere
tovariety
1953,
Aluminized
Steel
culverts
exposed
in sites
erosive
applications.
Test
installations
tions2including
farm sites
field
drainage,
Type
andU.S.
galvanized
steel
across
the
These
reprewerewater
sampled
after 8 years
andsoils,
again
fresh
swamps,
alkali
culverts
were
exposed
in sites
sented
a24
variety
of service
condiafter
years.
Weight
loss
data
analyzed
andincluding
erosive
Test
across
the U.S.applications.
These
sitesdrainage,
repretions
farm
field
at all sites indicate
Aluminized
Steel
installations
were
sampled
afterType 2
sented
a
variety
of
service
condifresh
water
swamps,
alkali
soils,
provided significant additional corrosion
eight
yearsapplications.
and
again
tions
including
farm
fieldafter
drainage,
and
erosive
Test 24
resistance.
years.
Weight
data
fresh
water
swamps,
alkalianalyzed
soils,
installations
wereloss
sampled
after
at
all
sites
indicate
Aluminized
and
applications.
Test
eight
years and
24andSteel
Inerosive
addition
to
theagain
careful after
sampling
Type
2 provided
significant
addiinstallations
were
after
years.
Weight
losssampled
dataduring
analyzed
evaluation
accomplished
this
24
tional
corrosion
resistance.
eight
years
andsimple
again
after
24 Steel
year
program,
visual
inspection
at all
sites
indicate
Aluminized
In
addition
to
the
revealed
that: loss
years.
datacareful
analyzed
Type
2Weight
provided
significant
addisampling
and
evaluation
accomat
all sites
indicate
Aluminized
Steel
tional
corrosion
resistance.
plished
during
this
24-year
pro•
T
he
appearance
of
Aluminized
Steel
Type
provided
In 2addition
to significant
the careful addiType
2
was
clearly
superior
to
that
gram,
simple
visual
inspection
tional
corrosion
resistance.
sampling
and evaluation
accom- of
conventional
metallic
coating.
revealed
that:to
In addition
the
careful
plished
during
this
24-year
pro• The condition of Aluminized Steel
sampling
and
evaluation
accomgram,
simple
visual inspection
• The
appearance
Type
2 pipe inverts,ofa Aluminized
critical point in
plished
during
this
24-year
prorevealed
that:
Steel
Typedesign,
2 was
clearly
superior
durability
was
excellent.
gram,
simple
visual
inspection
to
that
of
conventional
metallic
• The appearance of Aluminized
revealed
that:
coating.
Steel
Type 2 was clearly superior
• to
Thethat
appearance
of Aluminized
of conventional
metallic
Steel
Type 2 was clearly superior
coating.
to that of conventional metallic
coating.
3
3
Performance proven by 50 year field test
50 year old Aluminized Steel Type 2 coupons taken from pipe inverts around the United States
Marshall County, IA
Installed 1952
Inspected 2003
Lafayette County, MO
Installed 1952
Inspected 2003
Greene County, IL
Installed 1953
Inspected 2003
Morgan County, IL
Installed 1952
Inspected 2003
Bernalillo County, NM
Installed 1952
Inspected 2005
Carter County, MO
Installed 1953
Inspected 2003
San Benito County, CA
Installed 1952
Inspected 2005
Decatur County, KS
Installed 1953
Inspected 2003
Pratt County, KS
Installed 1953
Inspected 2003
Dickenson County, KS
Installed 1953
Inspected 2003
San Juan County, WA
Installed 1953
Inspected 2005
Eldorado County, CA
Installed in 1952
Inspected 2005
AK Steel has inspected many more pipe sites around the United States, and these field research studies indicate a minimum 75 year
service life for Aluminized Steel Type 2 Corrugated Steel Pipe installed in the recommended environment.
AK Steel Corporation
9227 Centre Pointe Drive
West Chester, OH 45069
800.331.5050
www.aksteel.com
4
The information and data in this bulletin are accurate to the best of our knowledge and belief,
but are intended for general information only. Applications suggested for the materials are
described only to help readers make their own evaluations and are neither guarantees nor
to be construed as express or implied warranties of suitability for these or other applications.
AK Steel and the AK Steel logo are registered trademarks of AK Steel Corporation.
Revision 06.17.12
The product, engineering
and research information in
this literature is applicable
exclusively to AK Steel
Aluminized Steel Type 2.
Aluminized Steel Type 2