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Market Outlook 2018: A Sunnier Mood with a Few Caveats

Market Outlook 2018: A Sunnier Mood with a Few Caveats

The atmosphere at VMA’s 2018 Marke...

Is it Time to Toss Those Commissions?

Is it Time to Toss Those Commissions?

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Cybersecurity for Process Control

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Young Valve Professionals: Megan Johnston

Young Valve Professionals: Megan Johnston

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Industry Headlines

Crude Oil, Petroleum Product Exports Reach Record Levels

Thursday, 19 October 2017  |  Chris Guy

According to the U.S. Energy Information Administration ( EIA ), crude oil exports in the first half of 2017 increased by more than 300,000 barrels per ...

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Industry Headlines

Emerson Agrees to Acquire Paradigm

3 DAYS AGO

Emerson has agreed to acquire Paradigm for a purchase price of $510 million, reflecting a multiple of 13 times expected 2017 EBITDA. Paradigm will be joined with Emerson’s existing Roxar automation software. The acquisition is expected to close within the next 60 days, subject to various regulat...

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ValvTechnologies Receives ISO 15848 Certification

4 DAYS AGO

ValvTechnologies’ EcoPack technology has received ISO 15848-1:2015 certification from Odin Heavy Industries. To earn ISO 15848 certification, ValvTechnologies underwent a stringent evaluation process that included a series of 17 helium leak tests and eight thermal cycles on a fully assembled v...

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Crude Oil, Petroleum Product Exports Reach Record Levels

2 DAYS AGO

According to the U.S. Energy Information Administration ( EIA ), crude oil exports in the first half of 2017 increased by more than 300,000 barrels per day (b/d) from the first half of 2016, reaching a record high of 0.9 million b/d. Petroleum product exports also grew over the same period with propan...

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Energy Intensity in U.S. Manufacturing Decreased

2 DAYS AGO

Energy intensity in manufacturing in the U.S. decreased from 2010 to 2014. U.S. manufacturing overall fuel intensity decreased by 4.4% from 3.016 thousand British thermal units (Btu) per dollar of output in 2010 to 2.882 thousand Btu in 2014. According to the Manufacturing Energy Consumption Survey (M...

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Fed Reports Economy Growth in September, Early October

2 DAYS AGO

Reports from all 12 Federal Reserve Districts indicated that economic activity increased in September through early October, with the pace of growth split between modest and moderate. The Richmond, Atlanta, and Dallas Districts reported major disruptions from Hurricanes Harvey and Irma in some areas a...

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Industrial Production Up 0.3% in September

3 DAYS AGO

Industrial production rose 0.3% in September. The rates of change for July and August were notably revised; the current estimate for July, a decrease of 0.1%, was 0.5% lower than previously reported, while the estimate for August, a decrease of 0.7%, was 0.2% higher than before. Manufacturing output...

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Addressing Welding Procedures Not Covered by ASME Section IX

materials_q_and_a_graphicQ: My customer has rejected my welding procedure specification (WPS) and has asked me to address items that are not required by ASME Section IX. Is this reasonable?

A: Yes, this is a reasonable request. In many cases, it is a good idea to address items not covered by Section IX1.

Many people view any given ASME code section as a handbook, and assume that if they follow everything in that code section, they have met all necessary requirements. However, each ASME code section has verbiage in the foreword warning the user that merely following the rules in that particular section will not ensure an adequate design. Such wording is phrased in ways like: “The user of the Code should refer to other pertinent codes, standards, laws, regulations or other relevant documents,” and “it is not intended that this Section be used as a design handbook; rather, engineering judgment must be employed in the selection of those sets of Code rules suitable to any specific service or need.”

For example, Section IX does not impose enough controls to ensure reliable weld joints because it does not address the proper choice of filler materials. Section IX would allow welding nickel alloys or copper alloys together using carbon steel filler, provided the qualification specimen passed the appropriate mechanical tests. Many variables are not required to be addressed in a Section IX WPS. But in many of these cases, a WPS that does not address those variables may not produce consistently reliable weld joints or provide adequate guidance to the welder, both of which should be the primary purpose of the WPS.

The following are examples of factors Section IX does not require, but that should be considered for inclusion in a WPS:

1. There are supplementary essential variables not required to be addressed for a WPS to be used on materials that are not impact-tested. One such essential variable is heat input, which is calculated based on current, voltage and travel speed. If heat input does not need to be addressed, Section IX does not require including voltage or travel speed values. Some of the software packages for creating WPS documents will even omit this information automatically. On the other hand, if no voltage or travel speed values are specified, it is possible to follow the WPS and still produce unacceptable welds. Therefore, even though not required by Section IX, it is beneficial to include reasonable voltage and travel speed values on the WPS—even for materials that are not impact-tested.

2. For a WPS that involves carbon and alloy steels postweld heat-treated (PWHT) below the lower transformation temperature (LTT), Section IX only requires the WPS to indicate the PWHT must be below the LTT.

Most WPSs for non-impact-tested carbon steels and alloy steels will actually state a PWHT temperature, but many omit the tolerance on this temperature and any soak time requirements.

To ensure that proper strength, ductility and hardness requirements are met, a PWHT temperature range should be stated on the WPS. That temperature range should be based upon the PWHT temperature used on the qualification coupon, taking into consideration the effects of higher and lower temperature on the strength, ductility, hardness and toughness of the material. In addition, as a function of base metal thickness, guidance should be provided regarding the soak time, as well as providing absolute minimum and maximum allowable soak times. Again, strength, ductility, hardness and toughness of the material should be taken into account.

3. Section IX does not prohibit combining procedures that have been qualified in different ways, such as procedures qualified with and without PWHT, or procedures qualified with and without controls required for impact-tested materials. In fact, creating one WPS that covers non-impact-tested material (such as WCC) and impact-tested material (such as LCC), with and without PWHT is both possible and allowed. These procedures are handy when it is necessary to get a customer review. However, the combined procedures tend to be difficult for welders to follow because they usually contain a number of notes and tables, and for any given job it can be hard to determine what information actually applies.

Although the combined approach is allowed, and although the combined document might be convenient from a creation and maintenance standpoint, it is actually better to create four separate WPS documents (non-impact without PWHT, non-impact with PWHT, impact without PWHT and impact with PWHT), because each WPS will then convey much more clearly the specific requirements for the pertinent situation.

In summary, although Section IX imposes an abundance of rules for qualifying and writing WPSs, there are many instances where additional controls and information need to be conveyed to ensure results that meet the intended requirements of the weld. Therefore, if your customer makes a comment on your welding procedure, view it as a possible learning experience. In the end, your WPSs will be better for it.

Reference:

ASME Boiler and Pressure Vessel Code, Section IX, “Qualification Standard for Welding and Brazing Procedures, Welders, Brazers, and Welding and Brazing Operators,” American Society of Mechanical Engineers, New York, NY, USA.


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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