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Achieving Predictable Valve Performance for Safety Applications

Achieving Predictable Valve Performance for Safety Applications

A focus on having the proper specificati...

Putting Servo Valves Back to Work

Putting Servo Valves Back to Work

Industries as varied as paper production...

Corrosion and Fouling: Is There a Solution?

Corrosion and Fouling: Is There a Solution?

According to a 1998 study released by the ...

Valves with All the Trimmings

Valves with All the Trimmings

The term valve trim has been around for ...

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Industry Headlines

Leading Economic Indicators Rose in January

Friday, 23 February 2018  |  Chris Guy

The Conference Board Leading Economic Index (LEI) for the U.S. increased 1.0% in January to 108.1, following a 0.6% increase in December, and a 0.4% i...

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Valve Positioners Offer Improved Control Valve Performance

Valve Positioners Offer Improved Control Valve Performance

Monday, 19 February 2018  |  David Matherly

From time to time, we are re-posting well-received or particularly valuable articles that have previously run on VALVEMagazine.com so that those who m...

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Industry Headlines

MRC Global Announces Fourth Quarter 2017 Results

3 DAYS AGO

MRC Global’s sales were $903 million for the fourth quarter of 2017, which was 26% higher than the fourth quarter of 2016 and 6% lower than the third quarter of 2017 due to seasonality. As compared to 2016, all sectors increased driven primarily by midstream and upstream.

MRC Global's fourth qu...

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Curtiss-Wright Acquires Dresser-Rand Government Business

4 DAYS AGO

Curtiss-Wright has entered into an agreement to acquire the assets that comprise the Dresser-Rand Government Business (Dresser-Rand), a business unit of Siemens Government Technologies, for $212.5 million in cash.

Dresser-Rand designs and manufactures mission-critical, high-speed rotating equipment sol...

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U.S. Refiners Increasingly Turning to Export Markets

3 DAYS AGO

“U.S. gasoline consumption has leveled off as the stimulus provided by low and falling oil prices between 2014 and 2016 has faded, so refiners are increasingly turning to diesel and customers in emerging markets,” Reuters  reports .

“In geographical terms, the fastest growth in co...

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$900M Power Plant Planned for Indiana

3 DAYS AGO

Vectren Energy Delivery of Indiana is proposing to install an additional 50 megawatts (MW) of universal solar and build an 800 to 900-MW natural gas-fired generation facility in addition to other critical investments that will significantly change the way the company generates power for the region .

Th...

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Leading Economic Indicators Rose in January

1 DAY AGO

The Conference Board Leading Economic Index (LEI) for the U.S. increased 1.0% in January to 108.1, following a 0.6% increase in December, and a 0.4% increase in November.

“The U.S. LEI accelerated further in January and continues to point to robust economic growth in the first half of 2018. Whi...

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IHS Markit Manufacturing Index Rose in February

2 DAYS AGO

U.S. manufacturers reported a strong upturn in business conditions during February, which continued the positive trend seen at the start of 2018. At 55.9, up from 55.5 in January, the seasonally adjusted IHS Markit Flash U.S. Manufacturing Purchasing Managers’ Index (PMI) pointed to the fastes...

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NACE MR0175/ISO 15156

materials_q_and_a_graphicQ: I see that there is a new version of NACE MR0175 called NACE MR0175/ISO 15156. Why did MR0175 become an ISO standard, and how do the requirements in the ISO version differ from those in the previous version?

A: This topic is too broad to cover completely in a column of this size. However, we would like to offer a brief history and a summary of one major change that will affect valve companies and their suppliers.

You may recall that MR0175-2003 invoked some major changes compared with the 2002 revision. Many of these changes were encouraged by the European Federation of Corrosion (EFC). The EFC had already issued two reports closely related to MR0175: Publication 16, "Guidelines on Materials Requirements for Carbon and Low Alloy Steels for H2S-Containing Environments in Oil and Gas Production," and Publication 17, "Corrosion Resistant Alloys for Oil and Gas Production: Guidance on General Requirements and Test Methods for H2S Service" ISO requested that NACE work to merge MR0175 and these documents into a single ISO standard. The "rewrite" of MR0175, which was eventually published as MR0175-2003, was the first step in that merger.

The biggest change in the 2003 version was the introduction of environmental application limits (such as maximum H2S partial pressures, maximum temperature limits, pH restrictions) for almost all of the CRAs (corrosion-resistant alloys-the various classes of stainless steels, nickel alloys, titanium alloys, etc). Some materials were actually deleted from the document (N06600 and N04400, to name two). However, for the materials that remained, there were few changes in actual metallurgical requirements. MR0175-2003 was then converted into ISO 15156, which was published in December 2003. In North America, it is sold by NACE as NACE MR0175/ISO 15156.

NACE MR0175/ISO 15156 is actually published in three parts:

  • Part 1: General principles for selection of cracking-resistant materials
  • Part 2: Cracking-resistant carbon and low-alloy steels, and the use of cast irons
  • Part 3: Cracking-resistant CRAs (corrosion-resistant alloys) and other alloys

The format of the document changed dramatically from that of the MR0175-2003 standard. The PDF version of MR0175-2003 was 44 pages. The three-part ISO version totals 147 pages. Although much of this expansion is due to the different format of the ISO standard, some new information was added (such as information about H2S-related cracking mechanisms other than sulfide stress cracking), and some new metallurgical requirements were imposed.

The environmental restrictions that originated in MR0175-2003 were passed along to the ISO 15156 document with essentially no changes, which means that selection of materials will not be affected vs. MR0175-2003.

Obviously, there are many new requirements that need to be evaluated by each manufacturer. However, the change that will most affect equipment suppliers and their foundries relates to new requirements for the qualification of welding procedures. NACE MR0175/ISO 15156 provides much more specific requirements for qualification of welding procedures than previous versions of MR0175. All procedure qualifications are required to include hardness surveys, whether or not post-weld heat treatment is performed. The hardness surveys must be performed using either 10 kg or 5 kg Vickers (HV 10 or HV 5) or Rockwell 15N (HR15N), and the indentations must be located according to specific survey layouts provided in the standard. Hardness surveys performed using Rockwell C (HRC) are allowed only if the design stress does not exceed two-thirds of specified minimum yield strength and if the welding procedure specification requires postweld heat treatment. Therefore, in most cases the use of HRC will not be acceptable.

The major implication of this new requirement is that it applies to all material categories, even those that are not hardenable by heat treatment. One normally associates the use of hardness surveys with the qualification of procedures for alloys that are hardenabled by heat treatment, such as the carbon steels, alloy steels, martensitic stainless steels, and duplex stainless steels. Materials that are not hardenable by heat treatment usually are exempt from these kinds of tests. Per ISO 15156, even procedure qualifications for austenitic stainless steels and solid-solution, nickel-based alloys must include hardness surveys. Most equipment suppliers, including valve manufacturers, likely did not perform hardness surveys for these types of materials, and even hardness surveys included in existing procedure qualifications for materials hardenable by heat treatment are very unlikely to have been performed per the layout specified in the new standard.

These new requirements mean that foundries and valve manufacturers will need to update existing procedure qualifications by either performing the hardness surveys on leftover procedure qualification coupons (if they happen to still be available), or by creating new weld coupons for the hardness surveys. When the range of alloys supplied into sour applications is considered, updating welding procedures to meet these new requirements will consume a great deal of time and expense.

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