06282016Tue
Last updateTue, 28 Jun 2016 8pm

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Fugitive Emissions—Issues and Opportunities

Fugitive Emissions—Issues and Opportunities

Fugitive emissions, ppm, consent decrees...

Problem-Driven Innovation

Problem-Driven Innovation

Developing Alternative Technology to Imp...

Valve Repair Takes Center Stage in Houston

Valve Repair Takes Center Stage in Houston

Attendees gathered June 2-3 in Houston t...

What Internal Best Practices Can Do for Valve Selection

What Internal Best Practices Can Do for Valve Selection

As time goes by, technology moves forwar...

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Industry Headlines

Oil Sands Production Forecast to Grow by Nearly 1M bpd

Tuesday, 28 June 2016  |  Chris Guy

IHS, in its outlook for Canadian oil sands production through 2025, expects continued growth through the period. IHS anticipates a new phase driven pr...

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Industry Headlines

MSS Publishes Revised Standard for High Pressure Knife Gate Valves

7 HOURS AGO

The Manufacturers Standardization Society (MSS) announces that recently revised Standard Practice, SP-135-2016, High Pressure Knife Gate Valves, has been approved by the American National Standards Institute (ANSI) as an American National Standard (ANS).

The first edition of MSS SP-135 was published in...

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Admiral Valve Joins VMA

7 HOURS AGO
Admiral Valve Joins VMA

This week the Valve Manufacturers Association (VMA) welcomed Admiral Valve LLC dba CPV Manufacturing , our sixth new member in 2016.

Admiral Valve, LLC designs and manufactures high-performance filtration systems for marine and aerospace use from their 30,000 square foot facility in the Philadelphia su...

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Oil Sands Production Forecast to Grow by Nearly 1M bpd

2 HOURS AGO

IHS, in its outlook for Canadian oil sands production through 2025, expects continued growth through the period. IHS anticipates a new phase driven primarily by the expansion of existing facilities with more attractive economics.

Oil sands production is forecast to grow by nearly one million barrels pe...

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Construction of Chemical Processing Facilities Begins in Louisiana

2 HOURS AGO

This month, LACC LLC, the joint-venture company formed by Axiall Corporation and Lotte Chemical Corporation, held a groundbreaking ceremony at its Calcasieu Parish, LA construction site. This follows a Dec. 17, 2015 announcement that the boards of Lotte and Axiall reached final investment decisions ...

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Consumer Confidence Climbs to 8-Month High

7 HOURS AGO

The Conference Board Consumer Confidence Index, which had decreased in May, improved in June. The Index now stands at 98.0 , up from 92.4 in May. Those stating business conditions are “good” increased slightly from 26.1% to 26.9%, while those saying business conditions are “bad&rdquo...

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How Will Brexit Affect the Manufacturing Industry?

1 DAY AGO

The day after the Brexit decision, National Association of Manufacturers (NAM) chief economist Chad Moutray addressed the UK vote to leave the EU and its effect on the manufacturing industry as well as the element of uncertainty it adds to the global marketplace.

According to Moutray, “If you are...

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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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