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How to Choose the Best Rapid Prototyping Method

How to Choose the Best Rapid Prototyping Method

As new products are designed, including ...

Monitoring Valve Health via the Internet

Monitoring Valve Health via the Internet

Most valve end users are already using s...

Valves in Oxygen Service

Valves in Oxygen Service

In his presentation at VMA’s 2017 ...

Thermal Spray Coating

Thermal Spray Coating

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Industry Headlines

Crane Co. Reports Second Quarter Results

Tuesday, 25 July 2017  |  Chris Guy

Crane Co. reported second quarter 2017 earnings of $1.14 per diluted share, compared to $1.15 per share in the second quarter of 2016. Excluding Specia...

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The Actuation Selection Process

The Actuation Selection Process

Tuesday, 25 July 2017  |  Carlos Gamero

A common misconception in our industry is that actuating a valve is as simple as putting the most cost-efficient actuator on top of your valve of choi...

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Industry Headlines

Crane Co. Reports Second Quarter Results

-1 DAYS AGO

Crane Co. reported second quarter 2017 earnings of $1.14 per diluted share, compared to $1.15 per share in the second quarter of 2016. Excluding Special Items, second quarter 2017 earnings per diluted share were $1.17, compared to $1.21 per share in the second quarter of 2016.

Second quarter 2017 sale...

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Badger Alloys Joins VMA as Associate Member

7 DAYS AGO

This week the Valve Manufacturers Association (VMA) welcomes Badger Alloys as an official associate supplier member. This is VMA’s fourth new member in 2017.

Located in the heart of Milwaukee and founded in 1966, Badger Alloys offers single source capabilities for custom castings. The company pou...

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U.S. Chemical Production Moved Higher in June

27 MINS AGO

According to the American Chemistry Council (ACC), the U.S. Chemical Production Regional Index (U.S. CPRI) edged higher by 0.3% in June, following a 0.3% gain in May, and a 0.4% decline in April, as measured on a three-month moving average (3MMA) basis. During June, output grew in all regions except t...

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U.S. Fuel Ethanol Production Continues to Grow in 2017

1 DAY AGO

Through the first six months of 2017, U.S. weekly ethanol production averaged 1.02 million barrels per day (b/d), an increase of 5% over the same period in 2016. On a weekly basis, U.S. ethanol production set a record of 1.06 million b/d in the week of January 27, 2017, and it has averaged near or a...

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IHS Market PMI Index Reached Four-Month High in July

3 HOURS AGO

July data revealed a further acceleration in business activity growth across the U.S. private sector. At 54.2, up from 53.9 in June, the seasonally adjusted IHS Markit Flash U.S. Composite PMI Output Index signaled the strongest rate of expansion since January.

The pickup in business activity growth ...

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IMF Lowers 2017 Growth Forecast for U.S.

1 DAY AGO

The growth forecast in the United States has been revised down from 2.3% to 2.1% in 2017 and from 2.5% to 2.1% in 2018, according to the IMF’s World Economic Outlook. While the markdown in the 2017 forecast reflects in part the weak growth outturn in the first quarter of the year, the major fa...

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Nickel-Copper Alloys

materials_q_and_a_graphicQ: Are the nickel-copper alloys (such as UNS N04400) acceptable for use in accordance with the NACE sour service standards?

 

A: This question has been asked frequently, usually in relation to a valve for an upstream hydrocarbon application involving sour water that also contains chlorides. Nickel-copper alloys can be an economical option for such applications. However, changes in the NACE standards within the last decade have complicated the issue.

The original version of NACE MR0175 released in 1975 allowed N04400 material with a 35 HRC maximum hardness requirement. In 1982, N04405, the higher-sulfur, free-machining version of N04400, was balloted, approved and added by addendum. M35-1 and M35-2, two cast “equivalents” of N04400, were balloted and added to a 1991 revision.

In addition to weak grades, the ­precipitation-hardenable N05500 was also included in the original 1975 ­version, with a maximum hardness of 35 HRC provided the material was hot-worked and age-hardened, solution-annealed, or solution-annealed and age-hardened.

When the MR0175 rewrite was under production as a precursor to ISO 15156, the weak grades (N04400, N04405, M35-1 and M35-2) were omitted for general usage and relegated to specific oil and gas field applications (i.e., they were no longer allowed for valve components). Many end users felt this alloy family was not needed for general sour upstream petroleum applications.

In addition, because of some field failures in N05500 fasteners, an effort was made to eliminate this material as well. In the end, N05500 was retained in the new standard, but was relegated to use in:

  • Wellhead and Christmas tree components other than bodies or bonnets, with specific pH and hydrogen sulfide partial pressure restrictions
  • Non-pressure-containing internal components in valves, pressure regulators or level controllers, and
  • The same specific oil and gas field applications as soft alloys.

Because NACE defines valve shafts and stems as pressure-containing components, this material could no longer be used for shafts and stems when compliance with MR0175 was required.

Shortly after NACE MR0175-2003 was released, it was converted to ISO 15156, which NACE then adopted back as NACE MR0175/ISO 15156. No changes were made regarding the ­nickel-copper materials.

In the meantime, NACE MR0103, the downstream (oil refining) sour service standard, was released (in 2003), and included N04400, N04405, M35-1, M35-2 and M30C (another N04400 cast equivalent), as well as N05500 with the same metallurgical requirements that were specified in the pre-2003 versions of NACE MR0175. No restrictions regarding the types of components that could be made from the N05500 grade were made.

In 2005, ISO 15156-3:2003 Technical Corrigendum 2 (essentially an addendum to NACE MR0175/ISO 15156) was released, allowing use of N04400 and N04405 for general purposes. However, the cast grades were not included in this change.

When NACE MR0175/ISO 15156 Second Edition was published in 2009, N04400 and N04405 were inserted into the main document along with the other solid solution nickel alloys.

A summary of the acceptability of these various nickel-copper materials is shown in Table 1.

vmfall12_repair_table1

The ramification of this situation is that it is not possible to produce many valve designs using an all nickel-copper construction in accordance with the current version of NACE MR0175. If the body style requires a casting (such as a globe valve), the cast alloys are not permitted. In addition, N04400 and N04405 are rarely strong enough to use for shafts or stems, and N05500 is not allowed for those components.

Therefore, unless the valve body can be produced from a wrought material form such as a plate or forging, and the shaft can be made from the lower-strength N04400 or N04405, some other, non-nickel-copper material will need to be used for the body and the stem or shaft.


Don Bush is a principal materials engineer at Emerson Process Management–Fisher Valve ­Division (www.emersonprocess.com). Reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..

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