AL 29-4C Superferritic Stainless Tube UNS S44735
Type AL 29-4C is a superferritic stainless steel originally developed for power plant surface condenser tubing. The basic composition of 29% Chromium and 4% Molybdenum has proven to provide optimal corrosion resistance. As a result, this alloy has been used in a number of different environments including sea water and chemical applications.
AL 29-4C alloy is designed for extreme resistance to chloride ion pitting, crevice corrosion and stress corrosion cracking, as well as general corrosion in oxidizing and moderately reducing environments. The alloy was developed in the early 1980s for welded condenser tubing to be used in seawater and brackish water by the power generation industry. It is this extreme resistance to pitting and crevice corrosion that has led to the installation of over 2000 miles of AL-29-4C tubing in power plant condensers and heat exchangers.
The superferritic stainless steel AL 29-4C alloy shows excellent resistance to chloride ion pitting, crevice corrosion and stress corrosion cracking. This resistance makes it an ideal choice for battling the corrosive condensate of partially and fully condensing natural gas and propane burning appliances. Its low alloy content, compared to other high-performance alloys, makes it an economical choice as well.
Advantages:
1. High resistance to severe chloride environments, such as seawater
2. Better resistance to vibration damage than titanium
3. Better resistance to erosion-corrosion than titanium and copper base alloys
4. Better heat transfer properties than austenitic stainless steels
5. Low cobalt content
6. Cost effectiveness.
![]() Typical properties for AL 29-4C® Stainless Steel
|
Alloy
|
Temper
|
Tensile Strength
Minimum (psi)
|
Yield Strength
Minimum 0.2% offset (psi)
|
% Elongation
in 2" Minimum
|
AL 29-4C®
UNS S44735 |
Annealed
|
80,000
|
60,000
|
18%
|
|
Alloy
|
C
|
Mn
|
P
|
S
|
Si
|
Cr
|
Ni
|
Mo
|
Cu
|
N
|
Other (max)
|
|
AL 29-4C®
|
.03
|
1.00
|
.040
|
.030
|
1.00
|
28.00-30.00
|
1.00
|
3.60-4.20
|
-
|
.045
|
-
|
|
