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Valve Basics Training Helps Fill Industry Skills Gap

Valve Basics Training Helps Fill Industry Skills Gap

One of the most keenly felt needs in tod...

An End-User’s Perspective on Valve Selection and Risk

An End-User’s Perspective on Valve Selection and Risk

I am not a valve expert, although I ofte...

New Test Stamp and More Updates on Pressure Vessel Codes

New Test Stamp and More Updates on Pressure Vessel Codes

A new test organization program and stam...

The Role of Valves in HAZOP Studies

The Role of Valves in HAZOP Studies

Process hazard analysis (PHA) is require...

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ValvTechnologies Successfully Completes NUPIC Audit

3 DAYS AGO

ValvTechnologies, Inc. recently achieved NUPIC-approved suppliers list status, upon successful completion of the Nuclear Procurement Issues Committee (NUPIC) audit conducted at the Houston facility. NUPIC members include all domestic U.S. nuclear utilities as well as several international members.

Form...

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GE Oil & Gas Supporting ONGC’s Exploratory Drilling Campaign in India

3 DAYS AGO

GE Oil & Gas has been awarded a multi-million-dollar frame agreement by Oil and Natural Gas Corporation Limited (ONGC), India’s largest exploration and production company. Under the agreement , GE will provide an estimated 55 subsea wellheads (SG5) over next three years for the operator&rsqu...

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Chemical Activity Barometer Suggests Accelerated Business Activity

4 DAYS AGO

The Chemical Activity Barometer (CAB) expanded 0.4% in August following an upward revision for July. This marks the barometer’s sixth consecutive monthly gain. Accounting for adjustments, the CAB is up 3.2% over this time last year, the strongest year over year growth since January 2015. All d...

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Innovation Could Lead to Significant Cuts in Chemical Manufacturing Energy Use

4 DAYS AGO

Scientists from ExxonMobil and Georgia Tech have developed a new technology that could significantly reduce the amount of energy and emissions associated with manufacturing plastics. If brought to industrial scale, this breakthrough could reduce industry’s global annual carbon dioxide emissions ...

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Manufacturing Productivity in U.S. Higher Than Other Nations

2 DAYS AGO

“U.S. productivity unexpectedly declined for a third straight quarter in the three months through June, Labor Department figures showed. On a year-over-year basis, it fell for the first time since 2013,” Bloomberg reports .

But on a more positive note, “the U.S. still blows other natio...

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Durable Goods Orders Up 4.4%, a Six-Month High

2 DAYS AGO

New orders for manufactured durable goods in July increased $9.7 billion or 4.4% to $228.9 billion, the U.S. Commerce Department announced. This increase, up following two consecutive monthly decreases, followed a 4.2% June decrease. Excluding transportation, new orders increased 1.5%. Excluding def...

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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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