6/3/2015 The Secret to Fusion Welding Success ­ FABTECH

http://www.fabtechexpo.com/the­secret­to­fusion­welding­success/#.VPnVGPmG98A 1/5

November 9­12, 2015McCormick PlaceChicago, IL USA

EXHIBIT FIND HOUSING REGISTERNorth America's Largest Metal Forming, Fabricating, Welding andFinishing Event

Home | Contact Us | FAQ's

ATTENDFABTECH 2015SEARCHExhibitor DirectoryLEARNEducation ProgramEXHIBITReserve SpacePLANExhibitor ResourcesJOBBOARDFABTECHMEXICOFABTECHCANADAATTEND FABTECH 2013SEARCH — Exhibitor DirectoryLEARN — Develop Your SkillsEXHIBIT — Reserve SpacePLAN — Your ExhibitJOB BOARDFABTECH MEXICOFABTECH CANADAMenu...

The Secret to Fusion Welding SuccessWe’ve all heard the mantra about how to succeed in real estate: location, location, location. So is there somethingsimilar to summarize the key to success in fusion welding? Yes. It’s preparation, preparation, preparation.

The secret to fusion welding success is a Weld Execution Plan that outlines all product prerequisites as determinedthrough diligent planning and preparation. The quality of individual weld beads is proportional to the extent of

6/3/2015 The Secret to Fusion Welding Success ­ FABTECH

http://www.fabtechexpo.com/the­secret­to­fusion­welding­success/#.VPnVGPmG98A 2/5

planning and preparation performed prior to welding. A weldment, which may be comprised from a few to thousandsof individual weld beads, thus will reflect the amount of preparation conducted prior to welding. We can measure thesuccess of fusion welding, including hardfacing and cladding applications, by how accurately and thoroughly theWeld Execution Plan identifies and details all the prerequisites required to develop a high­integrity weld thatconsistently meets weld code criteria and the design for service and performance requirements.

Figure A.4 of AWS A3.0:2010, Standard Welding Terms and Definitions, lists 26 fusion welding processes.However, this article applies to eight of them: electron beam (EBW), laser beam (LBW), gas tungsten arc (GTAW),gas metal arc (GMAW), plasma arc (PAW), shielded metal arc (SMAW), submerged arc (SAW), and flux cored arc(FCAW) welding, in which there are common prerequisites to achieving a high­integrity weld.

Fusion welding is best viewed from the welder’s or welding operator’s perspective to fully garner an understandingof the criticality of performing thorough planning and preparation prior to welding.

The transient nature of a weld pool is unforgiving relative to coping with any adverse weld process and/or weld jointconditions. For example, if the weld joint is contaminated, joint fitup poor, preheat insufficient, or an incorrectwelding technique employed, the weld pool will react accordingly and discontinuities and/or defects such asincomplete fusion, cracks, undercut, slag inclusions, and porosity will develop. Beam/arc time is critical relative tothe time available for welders to manipulate and control weld pool behavior. Weld pool geometry and the surfacemorphography of the weld bead is a function of weld process parameters such as the preheat temperature andbeam/arc manipulation and control (e.g., travel speed, amperage, watts, torch/beam axis angle, arc/focal length,technique/oscillation, etc.), and weld joint attributes such as cleanliness, fitup, alloy chemistry, and base metalsurface finish. Respective to the individual process, additional criteria may include shielding gas composition, fillermetal alloy, electrical attributes, filament type and size, flux composition, etc. These all relate directly to thecontinuity of the weld bead solidification process, which is dependent upon the dynamics of the weld pool meltsuch that any detrimental or unfavorable aspect of the welding process and/or weld joint that may be present orintroduced during welding will prevent or inhibit the creation of an acceptable code­compliant weld.

Characteristics of a high­integrity weld bead include mechanical soundness, metallurgical homogeneity, and auniform profile/cross section. The tempo of welding and the rate at which the weld bead solidifies transpiresquickly, such that there is no compensating for inadequate planning and preparation once welding has begun. Thisis especially true for high travel speed (i.e., 20–110 in./min), programmable processes such as EBW and LBW, aswell as modest travel speed (i.e., 2–40 in./min) processes such as semiautomatic, automatic, and mechanizedFCAW, GTAW, PAW, FCAW, SAW, and GMAW, as well as in­situ SMAW downhill pipe welding, which has speedsof 4–17 in./min. A marked correlation exists between the extent of planning and preparation performed prior toproduction welding and formation of weld bead discontinuities or defects that affect the integrity of the weldment.

The Weld Execution Plan

A well­formulated weld execution plan will mitigate welding and fabrication risks. The plan should outline all theprerequisites that require resolution prior to production. These prerequisites include the following:

1. Implementation and enforcement of environmental, health, and safety and personal protection equipmentpolicies/practices for the protection of welders/operators, support personnel, equipment, and the environment.Employing ANSI Z49.1:2012, Safety in Welding, Cutting, and Allied Processes, and promoting an attitude of pre­vention and precautionary awareness is recommended.

2. Qualification of Procedure Qualification Records (PQRs) in accordance with the respective weld code for theactual production application. In other words, PQRs should be qualified based upon actual production weldingrequirements such as pipe wall or plate thicknesses, etc. Also, PQRs should be qualified utilizing a weld procedurequalification plan so there is agreement among all parties relative to weld variables like filler metals, preheating,etc.; and weld specimen nondestructive examination (NDE), mechanical and metallurgical testing, andenvironmental simulation testing. Reproducibility of qualified PQR weld variables is crucial to consistently achievehigh­integrity production welds — Fig. 1.

6/3/2015 The Secret to Fusion Welding Success ­ FABTECH

http://www.fabtechexpo.com/the­secret­to­fusion­welding­success/#.VPnVGPmG98A 3/5

3. An in­depth knowledge of the metallurgical/weldability properties of the base metal alloys relative to crackingsusceptibility, postweld heat treatment, quenching and tempering, thermal conductivity, coefficient of thermalexpansion, hardenability, etc. Subjecting weld joint mockups to metallurgical/metallographic evaluation (e.g., micro­structure, microhardness); mechanical testing (e.g., yield strength, Charpy V­notch, fracture analysis); andenvironmental simulation testing (e.g., sour service, wet gas, humidity) are essential for critical applications.

4. Logistics and the production infrastructure. Production methodologies (e.g., fixturing, positioners, machine tools,pipeline shelters, etc.) need to be determined prior to the start of fabrication. A preventive maintenance and annualcalibration program for welding equipment is imperative. Base materials and welding consumables require properstorage to prevent contamination and damage. For critical applications, securing base metal and weld filler metalCertified Material Test Reports are vital as is maintaining material traceability and usage records.

5. The fostering of increased communication/production efficiencies. For example, you should conductproduction/project briefings so welders/operators, fitters, etc., develop an understanding of and increasedawareness of production/project criteria including objectives, expectations, health and safety policies, scheduling,etc., for the project. This will also let staff know what quality control and engineering support is available.Employing a preweld checklist at job site/workstation locations to help decrease welding­based errors, rework, andrepair activities is also helpful.

6. A realization of metallurgical and mechanical principles. These could include the following:

• Realizing the effects of weld solidification shrinkage forces, overwelding, the coefficient of thermal expansion, andbase metal thermal conductivity to reduce weldment distortion;

• Understanding the importance of eradicating weld joint stress risers by

a) Achieving code­compliant weld joint fitups;

b) Using the proper welding technique to achieve acceptable weld bead tie­ins, weld bead sequencing, andweld bead profiles as well as eliminating weld discontinuities/defects such as incomplete fusion, arc strikes,craters, undercut, etc.;

c) Employing skillful grinding/blending techniques.

7. Developing a quality manual that delineates policies and procedures pertaining to quality assurance/qualitycontrol oversight; a preventive maintenance and calibration program; fitup, in­process/in­service, and postweldinspection; hold points; weld maps; a foreign object debris and elimination program; positive material identificationand Certified Material Test Reports; material handling, storage, and traceability; documentation control;workmanship quality standards; and other pertinent items. The manual would also contain training and qualificationrequirements for welders, welding operators, fitters, weld inspectors, and other quality assurance personnel.

8. Fabrication/production drawings, including the drawing notes, that are accurate and unambiguous. Keep in mindthat it is also necessary to make sure weld symbols are in accordance with AWS A2.4: 2012, Standard Symbolsfor Welding, Brazing, and Nondestructive Examination. Details matter.

9. Welder/operator training, training and more training. Rigorous training is needed for the performance qualificationof welders/operators with respect to the weld code and the actual production application — Fig. 2. It is important toestablish fabrication competency and to instill confidence and pride in workmanship. Provide instruction and/or

6/3/2015 The Secret to Fusion Welding Success ­ FABTECH

http://www.fabtechexpo.com/the­secret­to­fusion­welding­success/#.VPnVGPmG98A 4/5

About FABTECHSupporting PublicationsExhibitor Advisory CouncilIndustry LinksHost City Info

Join Our Email ListSubscribe to the FABTECH 365Current Issue of FABTECH 365FABTECH CaresMedia Resources

More Information

verify knowledge regarding visual examination of welds, types of discontinuities, NDE concepts, weld codes,materials, drawing interpretation (e.g., weld symbols), weld filler metals, measuring tools, and fitup techniques.

10. A comprehensive understanding of the weldment application and optimization of weldment design. These wouldinclude weld joint design and preparation methodologies; weld sizing; selection of base and filler metal; purgingstrategy; weld process selection; and incorporation of design for manufacturability and assembly concepts (e.g.,design simplicity, fewer parts, reduced cost, etc.). Performing welding and NDE inspection on full­size weld jointmock­ups to verify weld joint accessibility/producibility is emphasized.

Conclusion

The secret to success in applications that employ the EBW, LBW, GTAW, GMAW, PAW, SMAW, SAW, andFCAW processes is a Weld Execution Plan that outlines all production prerequisites. A Weld Execution Planmitigates welding and fabrication risks by identifying and detailing items that must be addressed and resolved priorto the commencement of production. There are no shortcuts to achieving high­integrity welds on a consistent basis.A well­recognized and deeply rooted axiom rings true: “Proper planning and preparation performed prior toproduction prevents pitiful poor performance and propels productivity.”

Works Consulted

1. AWS D1.1:2010, Structural Welding Code — Steel, Annex I. Doral, Fla.: American Welding Society.

Lead Photo: A high­integrity, 347 stainless steel valve component hardfaced with a CoCrW alloy powder applied bythe plasma arc welding process.

Fig. 1 — A high­quality Inconel® 600 fillet weld produced with the GTAW process.

Fig. 2 — Before training, a welder made the aluminum weld on the left using GTAW. The welder made the weld onthe right after being instructed in welding technique, weld bead characteristics, weld parameters, and theimportance of base metal/weld joint cleanliness.

This article authored by William C. LaPlante, welding engineer, and AWS CWI, CWE with BPXA,Anchorage/Prudhoe Bay, Alaska.

Reprinted with permission: The Welding Journal.

6/3/2015 The Secret to Fusion Welding Success ­ FABTECH

http://www.fabtechexpo.com/the­secret­to­fusion­welding­success/#.VPnVGPmG98A 5/5

ArchiveSitemap

Show Video & PhotosShow Logos & Banners

Search for: Search

Connect with us:

FABTECH Co­sponsors:

©2014 FABTECH. All rights reserved. Privacy Policy Legal Stuff

©2014 FABTECH. All rights reserved.