Fill out the form to access the full technical article

Sanicro® 35 Bridges the Gap Between Stainless Steels and Nickel Alloys for Chemical and Refinery Industries

Our high alloyed austenitic stainless steel Sanicro® 35 is used globally by several chemical and refinery industries as it’s an excellent high-performance solution for highly corrosive environments.

Bridging the Gap

Sanicro® 35 can be used instead of conventional high nickel alloys and super austenitic alloys to support more cost-effective and efficient operations for industries including chemicals, refining, bio-refineries, biomass, waste gasification, and chemical recycling.

Chemical composition (nominal), % UNS N08935

C Si Mn P S Cr Ni Mo Cu N Fe
≤0.030 ≤0.4 0.8 ≤0.030 ≤0.020 27 35 6.5 0.2 0.30 Remainder

Corrosion Resistance and Versatility

Sanicro® 35 has extremely good pitting and crevice corrosion making it suitable where seawater is used for cooling or heating. It has a high resistance to general corrosion in acid environments. It can be used in heat exchanger applications such as overhead condensers and seawater coolers, hydraulic and instrumentation tubing, chlorinated hydrocarbon applications, and Purified Terephthalic Acid (PTA) environments. In the chemicals industry, it can be used with organic acids (such as formic and acetic acid) and inorganic acids (such as phosphoric acid and sulfuric acid) and is available in round bar, seamless pipe, and plates or sheets.

Comparison of pitting corrosion resistance between 904L, Alleima 254 SMO, and Sanicro® 35. Test according to ASTM G150 with 3 M MgCl2 as test solution.

Mechanical Properties and Cost Efficiency

With high mechanical strength and ductility, Sanicro® 35 enables thinner tube walls, improving heat transfer and lowering material costs. Its weldability with various alloys, including Alloy 625 and super duplex alloys, adds to its versatility.

Advancing Material Solutions for Refineries and Offshore Applications

Sanicro® 35 has excellent resistance to corrosion from ammonium chloride and ammonium bisulphide. This makes it a good alternative to Alloy 625 for overhead condensers and hydrotreater plants. It’s a cost-efficient option for use in renewable diesel and sustainable aviation fuel production.

Sanicro® 35 has excellent resistance to offshore marine and sour service environments. Its high resistance towards cracking in sour service conditions, lower alloying content compared to Alloy 625 and its high mechanical strength can lower the costs of hydraulic and instrumentation installations considerably.

Sanicro® 35 makes the difference

Sanicro® 35 has been successfully installed in refineries, chemical, petrochemical, and fertilizer plants across the globe. In most cases, it’s used as a material upgrade in failing shell and tube heat exchangers, replacing super duplex, hyper duplex, and 6Mo super austenitic grades. There is also lots of interest in Sanicro® 35 for greenfield projects as a cost-efficient alternative to Alloy 625, especially in renewable fuels applications.

Standards and Approvals

Sanicro® 35 complies with NACE MR0175/ISO 15156-3:2015, (Petroleum, Petrochemical, and Natural Gas Industries - Materials for Use in H2S-Containing Environments in Oil and Gas Production - Part 3: Cracking-Resistant CRAs (Corrosion-Resistant Alloys) and other Alloys) for Type 4a type 4c materials.

It complies with ANSI/NACE MR0103/ISO 17495-1:2016, (Petroleum, Petrochemical, and Natural Gas Industries - Metallic Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments) for highly alloyed austenitic stainless steels and nickel alloys.

Sanicro® 35 has an ASME code case, no. 2982, for Boiler & Pressure Vessel Code, section VIII, Division I & II, covering ASTM B163 (tubes), B649 (bars), B677 (pipes), and B625 (plate & sheet). Maximum temperature is currently 450°C, which will be updated in future revisions to 550°C (842°F).

For the EU Pressure Equipment Directive (PED), a Particular Material Appraisal (PMA) is available as TÜV file 1326W043219, covering tube, pipe, bar and sheet & plate products. Maximum temperature is 550°C (842°F).