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Localised corrosion Sanicro 35 has excellent pitting corrosion resistance with a PREN 1 ≈ 52, making it suitable for applications where chlorides are present. Its pitting corrosion resistance compared to other Alleima grades, using a modified ASTM G150 test, is shown in Figure 1 . A comparison of Sanicro 35 and Alloy 625 using another slightly modified ASTM G150 test method is shown in Figure 2 . The grade also exhibits good crevice corrosion resistance, and in ASTM G48 testing, it performs better than Alloy 625 and is at least on par with Alloy C-276 (see Figure 3 ). Environmental-induced cracking Chloride stress corrosion cracking (Cl-SCC) can easily lead to catastrophic failures if a pressurised shell or pipe cracks and releases process fluids into the environment. Several Cl-SCC tests have shown that Sanicro 35 has a very high resistance towards this corrosion mechanism. General corrosion Sanicro 35 has shown high corrosion resistance in caustic environments and high resistance towards sulphuric acid, making it suitable for a number of applications within the chemical process industry. In organic acids, it is beneficial with high chromium
Sanicro 35 from Alleima bridges the gap between stainless steels and nickel alloys
Sanicro 35 has been developed for highly corrosive environments in demanding industries like chemicals and refining. It also supports ‘green’ technologies such as chemical recycling and renewable fuel production. It bridges the corrosion resistance gap between super austenitic stainless steel grades and more expensive high nickel alloys, making it an attractive upgrade material. Its chemical composition is shown below:
Sanicro 35 chemical composition (nominal) % C Mn P S Si Cr
Ni
0.030 1.2
0.030
0.020
0.5
27
35
Mo 6.5
Cu 0.4
N
Fe
0.3 Remainder
Sanicro 35 has very high mechanical strength compared to other super austenitic and nickel base alloys. The yield strength for heat exchanger and hydraulic and instrumentation (H&I) tubing is 425 MPa (62 ksi). In addition, it has high ductility, resulting in good cold forming properties.
100
120
60 40 50 80 70 20 10 30 90
80 100
60
40
20
0
0
Sanicro® 35
Alloy 625
Figure 1 Comparison of pitting corrosion resistance between Sanicro 35 and other Alleima grades. Test according to ASTM G150 with 3 M MgCl2 as test solution
Figure 2 Comparison of pitting corrosion resistance between Sanicro 35 and Alloy 625. Test according to ASTM G150 with 4.5 M MgCl2 at pH = 5 as the test solution
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