Bridging the Gap to Improved Heat Exchanger Performance with Sanicro® 35

By Jennifer Svensson, Sales Manager, Heat Exchanger and H&I

From seawater coolers to condensers, when it comes to heat exchanger applications, Sandvik Materials Technology’s Sanicro® 35 offers a viable alternative to austenitic or super-austenitic steel grades and nickel alloys.

For fabricators, Sanicro® 35 requires no pre-heating or post-weld heat treatment. Its high structural stability means it’s not prone to intermetallic phases during welding. The excellent formability of the grade permits cold bending to tight bending radii. Cutting, turning, drilling, and milling are also easier than with a tough nickel alloy tube.

With Sandvik having recently received its first full order for Sanicro® 35 heat exchanger tubes, we thought it would be worthwhile to look at why our customers are excited about this new grade and what makes it so special.

Opening Up More Opportunities

Sanicro® 35 is a highly allowed and chemically balanced PRE 52 super-austenitic grade that offers extreme pitting resistance and outperforms conventional 6Mo alloys. The material’s ability to provide a high level of corrosion resistance and strength gives it an excellent price performance ratio compared to alloys with a higher nickel content. Furthermore, its high structural stability provides reassurance that it will maintain its microstructure after welding, so the weld area is not a weak point when in service. This helps minimize risks and extends the lifecycle when battling corrosion.

Combining the mechanical properties of duplex grades with localized crevice corrosion resistance comparable to alloy C276, Sanicro® 35 (UNS N08935) has a critical pitting temperature (CPT) of 110°C per ASTM G150 in a modified and more severe 3M Magnesium Chloride (MgCl2) buffer. Its high yield strength enables reduced wall thicknesses, creating significant weight savings. It also has a very high resistance to stress corrosion cracking.

Easier Fabrication

Fabrication of the tubes for the two heat exchangers in the crude unit fractionator on the U.S. Gulf Coast was undertaken by Brask Inc, and feedback has been extremely positive. Brask has fabricated heat exchanger bundles for the same end client from hyper-duplex SAF 2707 HD in the past and using Sanicro® 35 this time, the fabrication performance was equally impressive.

Dinesh Bakshi, Vice President of Sales and Marketing at Brask, said: “We found Sanicro® 35 easy to work with and it performed as we expected. From our long-standing collaborative relationship with Sandvik, we were confident we would be able to fabricate successfully with Sanicro® 35, knowing we had the support of the Sandvik Technical Marketing and R&D teams behind us.

“Sandvik provided us with important information such as the code case details, the welding procedure number, and input on filler metal selection, ensuring fabrication went entirely to plan. When the end client requested earlier delivery, Sandvik stepped up, working tirelessly to meet new deadlines and even found a way to air freight the material from Europe.

“We were very happy with the performance of Sanicro® 35 and the support we received from Sandvik. Before we started, they supplied weld sample tubes in advance so our welders could practice on weld procedure. We found the workability of Sanicro® 35 was similar to duplex and hyper-duplex materials we have used in the past, so there was familiarity with it. The welding of the tubes to the tube sheet also went according to expectations.”

Available Wherever You Are

The strategic location of our mills around the world allows reduced shipping times, transportation costs, and lead times. This means Sandvik Materials Technology is ready to offer high-quality solutions to your challenges, whenever and wherever you need us.

The Best of Both Worlds

Excellent material properties, a broader temperature range than super and hyper-duplex and a price performance ratio that’s better compared to expensive nickel-based materials mean Sanicro® 35 is ready to meet the needs of today’s heat exchanger industry. Our first full order for heat exchanger tubes is just the beginning for a material that’s ready to bridge the gaps towards operational excellence.

Learn more about how Sanicro® 35 can benefit your heat exchangers.

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Name: Jennifer Svensson
Title: Sales Manager, Heat Exchanger and H&I
Business Unit: Tube Americas
Location: Houston, TX, USA


Name: Dinesh Bakshi
Title: Vice President of Sales and Marketing
Company: Brask, Inc.
Location: Pearland, TX, USA