12022016Fri
Last updateFri, 02 Dec 2016 4pm

i

Valves in a Cement Slurry Line

Valves in a Cement Slurry Line

Basically everywhere you look in modern ...

Triple Offset Butterfly Valves

Triple Offset Butterfly Valves

Since their introduction to the market m...

Digital Valve Control Leads to Increased Plant Availability

Digital Valve Control Leads to Increased Plant Availability

Surge is characterized by fast flow reve...

Cast vs. Forged: The Ongoing Debate Takes a New Direction

Cast vs. Forged: The Ongoing Debate Takes a New Direction

In the valve industry, the cast versus f...

The Weekly Report

New Products

  • ja-news-2
  • ja-news-3

Industry Headlines

Industry Headlines

VMA Members Among Plant Engineering 2016 Product of the Year Finalists

1 DAY AGO

Several VMA members are among this year’s Plant Engineering Product of the Year finalists. Emerson has products nominated in four different categories, while Siemens has several products nominated in a total of three different categories. Chesterton and Hunt Valve have products up for awards the...

Readmore

MSS Publishes Revised American National Standard for Steel Pipeline Flanges and Receives ANSI Approval

1 DAY AGO

The Manufacturers Standardization Society (MSS) announces that the substantially revised Standard Practice, SP-44-2016, Steel Pipeline Flanges, has been approved by the American National Standards Institute (ANSI) as a Revised American National Standard (ANS).

The first edition of MSS SP-44 was publish...

Readmore

U.S. Chemical Industry Remains Optimistic for 2017

1 DAY AGO

Moving into 2017, the U.S. Chemical Processing Industry continues to enjoy optimism about future investment, according to Industrial Info's 2017 Global Industrial Outlook . Much of this activity stems from the continued low cost of natural gas liquids (NGLs), a primary feedstock for building-block che...

Readmore

Hydraulic Institute Celebrates Centennial with New Logo

1 DAY AGO
Hydraulic Institute Celebrates Centennial with New Logo

The Hydraulic Institute (HI) will celebrate its centennial in 2017 with a new logo as part of a larger initiative to position HI for the next 100 years of service to the pump industry. The new logo is a key element of HI’s overall brand refresh and redesign process.

The logo includes a hidden &ld...

Readmore

U.S. Adds 178,000 Jobs, Unemployment Rate at 4.6%

2 HOURS AGO

The unemployment rate declined 0.3% to 4.6% in November, and total nonfarm payroll employment increased by 178,000, the Department of Labor reported today. Employment gains occurred in professional and business services and in health care.

Employment in construction continued on its recent upward trend...

Readmore

Third Quarter GDP Revised Up to 3.2% Growth

1 DAY AGO

Gross domestic product (GDP) in the U.S. increased at an annual rate of 3.2% in the third quarter of 2016, according to the second estimate released by the Department of Commerce. In the second quarter, real GDP increased 1.4%.

This new GDP estimate is based on more complete source data than were avail...

Readmore

Welding Procedure

materials_q_and_a_graphicQ: I need to qualify a welding procedure specification per Section IX of the ASME Boiler and Pressure Vessel Code. What are some of the basics I need to understand?

A: Section IX of the ASME Boiler and Pressure Vessel Code is very complex, and the rules for qualifying welding procedures vary depending upon the welding processes used and the materials being welded. However, a few of the fundamental concepts are often misunderstood, and gaining a firm understanding of those concepts will make it easier for a new user of this code section to figure out how it works.

Section IX Part QW (which covers welding) is divided into four articles—I, II, III and IV:

  • Article I covers general requirements.
  • Article II covers requirements for qualifying welding procedures.
  • Article III covers qualification of welders and welding operators (which is outside the scope of this article).
  • Article IV covers welding data—variables, material groupings, test specimen requirements, etc.


A good way to begin is to read articles I and II. There is no point “reading” most of article IV because it is primarily dedicated to describing variables. However, the text at the beginning of each major section should be reviewed, including QW-401 (description of variables), QW-420 (material groupings), QW-424 (base metals for procedure qualification) and QW-431 (F-Numbers). Also, the definitions in QW-490 should be reviewed, as some of the terms used in the text may not mean what they seem to imply.

The end goal is a viable welding procedure specification (WPS). The WPS is a document that states requirements regarding the materials that may be welded, which welding process must be used, the filler metal used, the minimum preheat temperature, welding parameters such as current, voltage, travel speed, interpass temperature, PWHT requirements, etc.

The WPS is based upon the successful creation of a welded qualification test coupon. The procedure qualification record (PQR) is a document that lists all pertinent data associated with the creation and testing of the qualification specimen.

A common misconception is that the WPS is written first, and then the test coupon is created to “prove” that the WPS is valid. In actuality, the qualification coupon is created first. The PQR document is written, and then the WPS is created based upon the PQR data. The rules in Section IX govern how the parameters specified in the WPS are determined using the PQR data as a basis.

VARIABLES

In Section IX parlance, a variable is a parameter or factor that has been determined to have an effect upon the welding characteristics or the resulting weldment. Section IX includes many variables, and has categorized them for various welding situations as “essential,” “nonessential” and “supplementary essential.”

For a given welding situation, an essential variable is one that has been identified as critical to the success of the welding process or to the properties of the resulting weldment. A change in an essential variable requires requalification of the welding procedure.

A nonessential variable is a variable that must be documented in the WPS, but which may be changed during an editorial revision without requalification of the procedure.

A supplementary essential variable is a parameter or factor that becomes an essential variable when the base material is required to be impact tested.

Lists of essential, supplementary essential and non-essential variables for various welding processes are listed in tables immediately following paragraph QW-250. For example, QW-253 covers SMAW joining, and lists the paragraphs that describe the essential, supplementary essential and nonessential variables that apply. Two examples of variables listed in QW-253, and their impact are:

  • QW-406.1 - Decrease > 100° F (55° C) is an essential variable. Paragraph QW-406.1 states: “QW-406.1 A decrease of more than 100° F (55° C) in the preheat temperature qualified. The minimum temperature for welding shall be specified in the WPS.”
    Therefore, assuming the PQR lists a preheat temperature of 150° F (65° C), the WPS can be written with a preheat temperature as low as 50° F (10° C). If creating or revising the WPS to utilize a preheat temperature below 50° F (10° C) is desired, the procedure would need to be requalified.
  • QW-406.3 - Increase > 100° F (55° C) (IP) is a supplementary essential variable. Paragraph QW-406.3 states: “QW-406.3 An increase of more than 100° F (55° C) in the maximum interpass temperature recorded on the PQR. This variable does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic material is solution annealed after welding.”


Since this is a supplementary essential variable, it only applies if the base material is required to be impact tested (such as ASME SA352 LCC). Assuming that is so, and assuming the PQR lists a maximum interpass temperature of 500° F (260° C), the WPS can be written with a maximum interpass temperature of up to 600° F (315° C). If creating or revising a WPS to increase the maximum interpass temperature to higher than 600° F (315° C) is desired, the procedure would need to be requalified.

Note there are many QW-4XX paragraphs that describe variables; however, the only ones that apply to the welding procedure are those referenced in the QW-25X tables for the welding processes being used.

A valid WPS lists all essential and non-essential variables (and supplementary essential variables if the base metal is required to be impact tested), and provides appropriate values for each.

New users of Section IX sometimes think they can just use the example forms in Section IX and fill them in based upon what seems “obvious.” This approach is unlikely to result in a procedure that properly addresses the variables. The best way to ensure a WPS is complete and correct is to use the QW-250 tables as a type of “index” to ensure that all appropriate variables are included and properly addressed, and to review the definitions in QW-490 to ensure all terminology is interpreted and used correctly.


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..

  • Latest Post

  • Popular

  • Links

  • Events

Advertisement

Looking for a career in the Valve Industry?

ValveCareers Horiz

To learn more, watch the videos below or visit ValveCareers.com a special initiative of the Valve Manufacturers Association