Products tagged with 'u-bending'

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Comparison of the Life Cycle Cost of Carbon Steel, Duplex Stainless Steels, Super Austenitic, and Nickel-Based Alloys for Crude Unit Overheard Condensers

Product Number: 51324-21175-SG

Author: Karen Picker; Luiza Esteves

Publication Date: 2024

$40.00

A refinery in the U.S. Gulf Coast had been using carbon steel tubes in two crude unit overhead condensers that suffered severe corrosion leading to premature failure after just 6 months in service. The metallurgy of the tube bundles was later upgraded to super duplex, UNS S32750, and hyper duplex stainless steel (DSS), S32707, which extended the service life to 12 months and two years, respectively. Failure analysis of the DSS indicated that the corrosion started as under-deposit corrosion. Selective corrosion occurred, where the ferrite phase suffered a preferential corrosion attack. Super Austenitic Alloy 35, UNS N08935, was recommended as an economical alternative to nickel Alloys 625 (UNS N0625 and C-276 (UNS N10276). Material selection and life-cycle cost analysis helped the end user select the super austenitic Alloy as the material of choice for the upgrade. The bundles have been in service for more than two years. This paper evaluates the materials selection process, fabrication cost, and life cycle cost analysis of the different Alloys used in these bundles since the first carbon steel upgrade through the present time.

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Evaluation Of The Suitability Of As Bent Super Duplex Stainless Steel UNS-S32750 Tubing For Refinery Sour Services

Product Number: 51321-16850-SG

Author: Yong-Joo Kim; Karen Picker

Publication Date: 2021

$20.00

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Resistance of U-bend and Integral Finned Duplex Stainless Steel UNS-S32205 and UNS-S32750 to Sulfide Stress Corrosion Cracking

Product Number: 51322-18038-SG

Author: Karen Picker, Luiza Esteves, Yong-Joo Kim

Publication Date: 2022

$20.00

The use of Duplex Stainless Steels (DSS) in refinery sour environments is governed by ANSI/NACE MR0103/ISO 17945NACE “Metallic materials resistant to sulfide stress cracking in corrosive petroleum refining environments” which limits DSS base materials to be used in Hydrogen Sulfide (H2S) services to a maximum hardness of 28 HRC for materials with a PREN ≤ 40 and to a maximum hardness of 32 HRC for those materials with PREN > 40.¹ These hardness values are in line with the hardness requirements of solution annealed as produced straight tubes, but when the heat exchanger design requires the use of integral finning or u-bend tubes, these are subject to significant work hardening that results in as bent and as finned heat exchanger tubes with hardness measurement as high as 418 HV0.5 or 35.6 HRC which clearly exceeds the allowable limits stated above.

Products tagged with 'u-bending'

Comparison of the Life Cycle Cost of Carbon Steel, Duplex Stainless Steels, Super Austenitic, and Nickel-Based Alloys for Crude Unit Overheard Condensers

Evaluation Of The Suitability Of As Bent Super Duplex Stainless Steel UNS-S32750 Tubing For Refinery Sour Services

Resistance of U-bend and Integral Finned Duplex Stainless Steel UNS-S32205 and UNS-S32750 to Sulfide Stress Corrosion Cracking

Association for Materials Protection and Performance