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Application of a Highly Corrosion-Resistant Nickel-Alloy in the Chemical Industry

There are hundreds of commercially available alloys in the market, which is utilized by various industries, including chemicals producers. However, depending upon the corrosiveness of the process conditions, choices of materials of construction can be limited. One of a highly corrosive condition is acidic chloride chemistry (like, hydrochloric acid) in which only a handful of alloys (like, Ni-Cr-Mo alloys) can provide a reasonable service life, which though depends upon the amount of chloride, operating temperature, and impurities level.

Product Number: 51323-19183-SG
Author: Ajit Mishra, John Doyle, Vinay Deodeshmukh
Publication Date: 2023
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$20.00
$20.00

Corrosion-resistant Nickel-alloys containing optimum amounts of chromium (Cr) and molybdenum (Mo) are extensively used in aggressive conditions (like, acidic chloride chemistry) in various industries, including the agrochemical sector. In the similar process conditions, stainless steels which are cheaper alternates to Ni-alloys, can fail from multiple corrosion modes. Among Ni-alloys, one of the commonly used in corrosive media is C-276 (UNS N10276). Despite the versatility of N10276, there has always been a need for alloys with even higher corrosion resistance to acidic chloride solutions. This need was satisfied to an extent by Ni-Mo alloys (like, B-2 (UNS N10665), B-3 (UNS N10675)) and some of the reactive metal alloys (like, Zr-702 (UNS R60702)). However, these alloys are rather expensive compared to N10276 and have poor tolerance in the presence of oxidizing species. To overcome these limitations, an alloy with improved resistance to acidic chloride solutions, relative to C-alloys, and sufficiently good resistant to oxidants was developed and commercialized and named HYBRID-BC1 (UNS N10362).


In recent years, a single pass heat exchanger (HE) made of N10276 used in a production step had experienced an accelerated corrosion attack and was, therefore, proactively targeted for annual replacement. This HE was exposed to methylene chloride and hydrochloric acid in both vapor and aqueous phases. Furthermore, the temperature inside the tubes was found to reach as high as 60 °C. A project was initiated to evaluate other materials of construction having a higher life-cycle cost advantage.


Field testing data on various alloys in conjunction with lab data, cost analysis of the HE, fabricability of N10362 and characterization of mock-up tubes, assisted in selecting N10362 as a better alternate to N10276. A recent inspection data on N10362 HE showed less than 10% attack on 85% of the tubes. For similar number of batches, damage from corrosion attack was found to be 4-5 times higher for N10276 HE. This is the first time a HE was approved, fabricated, and trialed from N10362 alloy.

Corrosion-resistant Nickel-alloys containing optimum amounts of chromium (Cr) and molybdenum (Mo) are extensively used in aggressive conditions (like, acidic chloride chemistry) in various industries, including the agrochemical sector. In the similar process conditions, stainless steels which are cheaper alternates to Ni-alloys, can fail from multiple corrosion modes. Among Ni-alloys, one of the commonly used in corrosive media is C-276 (UNS N10276). Despite the versatility of N10276, there has always been a need for alloys with even higher corrosion resistance to acidic chloride solutions. This need was satisfied to an extent by Ni-Mo alloys (like, B-2 (UNS N10665), B-3 (UNS N10675)) and some of the reactive metal alloys (like, Zr-702 (UNS R60702)). However, these alloys are rather expensive compared to N10276 and have poor tolerance in the presence of oxidizing species. To overcome these limitations, an alloy with improved resistance to acidic chloride solutions, relative to C-alloys, and sufficiently good resistant to oxidants was developed and commercialized and named HYBRID-BC1 (UNS N10362).


In recent years, a single pass heat exchanger (HE) made of N10276 used in a production step had experienced an accelerated corrosion attack and was, therefore, proactively targeted for annual replacement. This HE was exposed to methylene chloride and hydrochloric acid in both vapor and aqueous phases. Furthermore, the temperature inside the tubes was found to reach as high as 60 °C. A project was initiated to evaluate other materials of construction having a higher life-cycle cost advantage.


Field testing data on various alloys in conjunction with lab data, cost analysis of the HE, fabricability of N10362 and characterization of mock-up tubes, assisted in selecting N10362 as a better alternate to N10276. A recent inspection data on N10362 HE showed less than 10% attack on 85% of the tubes. For similar number of batches, damage from corrosion attack was found to be 4-5 times higher for N10276 HE. This is the first time a HE was approved, fabricated, and trialed from N10362 alloy.

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