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Weld Cracking VII “The Heat-Affected Zone” Conference
AWS Conference attendees are awarded 1 PDH (Professional Development Hour) for each hour of conference attendance. These PDH’s can be applied towards AWS recertifications and renewals.

June 9 - 10, 2009 — Columbus, Ohio
Chairman: Robert Irving
Co-chairman: David Farson
Coordinator: Natalia Lopez

The most perplexing problem in the welding industry has to be weld cracking. Back by popular demand, this two-day conference is for those who want or need to get a handle on any weld cracking situation.

8:50-9:00 AM
Welcome: Robert Irving, Chairman

9:00-9:35 AM
The Keynote Address
William A. Baeslack III, Provost, Case Western Reserve University, Cleveland, and formerly, Dean, College of Engineering, Executive Dean for the Professional Colleges, Professor of Industrial, Welding and Systems Engineering and Professor of Materials Science and Engineering, Ohio State University, Columbus, OH

In his address, Dr. Baeslack will be discussing the metallurgical origins of weld cracking in such high performance alloys as nickel-base materials and such high performance nonferrous alloys as aluminum and titanium and how those materials compare to weld cracking behavior in conventional and advanced steels.

9:35-10:10 AM
“The Rewards in Purchasing Filler Metal by the AWS 5.01 Specification”
William F. Newell, President, Euroweld Ltd., Mooresville                    

“The AWS A5.01 specification is organized in a logical order and is user friendly. Whether or not all, or part, of the criteria listed in the document for actual lot testing are used depends on the extent to which special criteria are needed to adequately describe the product(s) desired and to reduce the uncertainty of receiving a product that may not meet the procurer's specific needs. As a minimum, the manufacturer is required to have an established quality assurance system and is required to trace the product to some known lot that is unique to that manufacturer. This requirement also applies to those who repackage, relabel and resell another manufacturer’s product that is identified as meeting AWS specification and classification or having the AWS classification imprinted on the electrode.”

10:10-10:30 AM Coffee break

10:30-11:05 AM
“Cracking Problems with Grade 91 and Other Creep-Strength Enhanced Ferritic Steels”
Jeffrey Henry, Associate, Structural Integrity Associates, Inc., Chattanooga, TN

“There has been ample discussion over the last several years regarding the need for tight control of the processing of Grade 91 and the other creep-strength enhanced ferritic steels if the improved mechanical properties of these materials at elevated temperature are to be realized. However, failure to control the processing steps, and particularly the post-weld heat treat temperature, can substantially increase the risk of brittle fracture and/or stress-corrosion cracking in the weld. Other factors that can promote cracking at the weldment include deficient design (e.g., saddle welded branch connections), improper support of components, and poor choice of filler metal for dissimilar metal combinations. This talk will review the various reasons that welds in these materials crack, and discuss the appropriate strategies to avoid cracking.”

11:05-11:40 AM
“Hot Cracking in Aluminum Welds”
William Hamilto, Quality Assurance Manager, AlcoTec Wire Corp., Traverse City, MI

“The hot cracking of aluminum welds can be a function of contraction stresses or the hot-short tendency of certain weld compositions.  When contraction stresses are greater than the weld metal strength at the elevated temperatures of solidification, then cracking will develop in the weld metal itself.  In addition, welding procedures can develop alloy compositions within known hot-cracking sensitivity ranges.  The problem of hot cracking due to contraction stresses, may be avoided by applying welding techniques that overcome the natural volume change that occurs during the heating and cooling of aluminum.  In order to avoid hot-short cracking, it is necessary to understand the effects that alloying elements have on crack sensitivity and how the choice of joint design and the selection of a filler alloy can eliminate it.”

11:40-1:00 PM Lunch

1:00-1:35 PM
“New Technique Determines Solid-Liquid and Solid-State Phase Transformations During Processing”
Boian T. Alexandrov, Research Scientist, Welding Engineering Program, Dept. of Industrial Weldin and Systems Engineering, The Ohio State University, Columbus, OH

“A new technique has been successfully applied for in-situ determining the solidification ranges and solid-state phase transformation temperatures in welded joints of various alloy steels, non-ferrous alloys and Ni-base superalloys, and for development of continuous cooling transformation diagrams. In addition, phase transformation behavior during weldability testing, post-weld heat treatment, and casting has also been measured.”

1:35-2:10 PM
“Hot Cracking in Welding of Austenitic Stainless Steels”
Damian Kotecki, Damian Kotecki Welding Consultants, Inc., Mentor, OH

“The talk will focus on solidification cracking, liquation cracking and ductility dip cracking. Then attention will turn to the role of ferrite in preventing hot cracking and means of lessening hot cracking tendencies when ferrite cannot be obtained in the weld metal. Finally, hot cracking caused by foreign metal contamination will be discussed.”

2:10-2:30 PM Refreshment break

2:30-3:05 PM
“Induction Heating as a Tool for Minimizing the Risk of Weld Cracking”
Steve Latvis, Regional Manager, North & South America, Global Pipe Systems, Miller Electric Manufacturing Co., Appleton, WI

“Relatively new induction heating equipment is finding use in various industries for preheat and stress relief. The technology appears to be more cost effective than either resistance heating or flame heating. Air-cooled equipment is available for temperatures up to 400oF and liquid-cooled equipment for work up to 1,450oF.”

3:05-3:50 PM
“Fracture Mechanics – Operating with Defects”
Kyle Koppenhoefer, Principal, Advanced Computational and Engineering Services, Gahanna, OH 43230   

“One of the primary goals for welding engineers and welders is to produce structural welds that are free of defects. Unfortunately, welding defects cannot always be avoided or removed and some may develop during in-service loading. In these situations, applied fracture mechanics can determine the affect of these defects on service life. Theoretical fracture mechanics has been taught to engineers for many years. However, advancements in fracture mechanics, coupled with improved computational capabilities, have extended the application of fracture mechanics to practical problems of interest to welding engineers. This presentation will provide engineers with an understanding of how fracture mechanics can be applied to solve a range of challenges.”

Adjournment for the Day

9:00-9:35 AM
“Reheat Cracking in Weldments”
Jose E. Ramirez, Principal Engineer, Edison Welding Institute, Columbus, OH

"Reheat cracking has been observed in low-alloy steels, stainless steels, and nickel-base superalloys weldments. Reheat cracking is manifested by low rupture ductility and intergranular fracture along (prior) austenite grain boundaries. Reheat cracking typically occurs in the coarse-grained heat affected zone (CGHAZ) or high-temperature HAZ and occasionally in the weld metal.Understanding the effect of material chemical composition and microstructure, joint design, welding procedures, and post-weld heat treatment conditions on reheat cracking is of paramount importance to obtain crack-free weldments."

9:35-10:10 AM "Understanding and Preventing Solidification Cracking in Fusion Welds"
John N. DuPont, R.D. Stout Distinguished Professor, Dept. of Materials Science & Engineering, Assoc. Director, Energy Research Center, Lehigh University, Bethlehem,PA

“Solidification cracking is one of the most common defects that can occur during fusion welding of engineering alloys. The cracking susceptibility is controlled primarily by alloy composition and resultant solidification behavior of the alloy. This presentation will outline the mechanism of solidification cracking, describe the use of the Varestraint test for determining the relative cracking susceptibility of engineering alloys, and illustrate methods for avoiding solidification cracking in welds.”

10:10-10:30 AM Coffee break

10:30-11:05 AM
“How AWS D1.1 Mitigates Weld Cracking”
Duane K. Miller, Manager, Welding Technology Center, and welding design consultant, The Lincoln Electric Co., Cleveland, OH

“The AWS D1.1 Structural Welding Code--Steel is the preeminent welding standard when it comes to structural steel welding in the U.S. To mitigate the potential of cracking that could occur during fabrication or erection, whether the cracks are "hot" or "cold", myriad requirements have been codified in this standard. Code requirements governing base and filler metals, preheat and interpass temperatures, joint design details, welding procedures specifications and fabrication techniques will be reviewed. Not only will this presentation serve as a primer on the use of D1.1, it will also serve as an example of a comprehensive method of controlling weld cracking, applicable to nonstructural steel industries.”

11:05-11:40 AM
“Temper Bead Welding Technique: An Alternative to Stress-Relieving Welded Repairs”
Patrick Nightengale, Senior Staff Engineer, Training Specialist, National Board of Boiler and Pressure Vessel Inspectors, Columbus, OH

“On occasion it may be inadvisable or impractical to perform postweld heat treatment (PWHT) of welded repairs to boilers and pressure vessels. The National Board Inspection Code (NBIC) includes alternatives to performing PWHT required by the original code of construction. Depending on the material properties and welding process selected, the alternative may simply require controlled preheat, or preheat and interpass temperature, or may require the repair be performed using the temper bead welding technique. The alternative requirements to performing PWHT will be reviewed and discussed.”

11:40-1:00 PM Lunch

1:00-1:35 PM
“How to Avoid Cracking in Titanium Welds”
John Lawmon, Principal Engineer, American Engineering & Manufacturing, Inc., Sheffield, OH

“The most popular titanium alloys are the commercially pure grades and Ti-6Al-4V alloys. These alloys offer good weldability under most conditions as long as proper procedures are used to assure protection from contamination. Weld cracking can be a result of contamination of the weld metal or heat-affected zone. Hydride precipitation; interstitial embrittlement, and stress corrosion are the main causes of cracking. In addition, heat treatable alloys can suffer from brittle microstructures that are related to martensitic transformations. These cracking conditions can be avoided by using proper cleaning, welding, shielding, and heat treating procedures.”

1:35-2:10 PM
“Measuring Residual Stress Using X-Ray Diffraction”
Robert Drake, Lab Sales, Proto Manufacturing Ltd, Oldcastle, Canada

“Residual stresses in weldments, if undetected, can lead to such problems as stress corrosion cracking or even fatigue cracking. But it is often difficult to determine whether heat treatment or shot peening can be used to cure such conditions without prior knowledge of the residual stress state. X-ray diffraction is being used to provide the information needed. Welding fabricators can buy this type of equipment or they can be serviced on site by trained inspectors equipped with portable x-ray diffraction equipment.”

2:10 - 2:30 PM Refreshment Break

2:30-3:05 PM
"Quality Improvements in Heat Treatment"
Gary Lewis, Director of Business Development, Superheat FGH, Mooresville, NC

“A significant percentage of weld anomalies and material deviations in new alloys (creep strength enhanced ferritic steels) are being attributed to improper heat treatment. Advancements in equipment technology, software and process control solutions, with renewed emphasis on shoring up weld procedures and industry codes, are revolutionizing traditional business models and enhancing quality assurance, at a number of levels, beneficial to plant owners, welding engineers and construction contractors.”

3:05-3:50 PM
“Ultrasonic Phased Array Testing Well Suited for Weld Inspection and Crack Detection”
Michael Moles, Senior Technology Manager, Olympus NDT Canada, Toronto, ON

“Ultrasonic phased array testing is a giant step up from many of the conventional ultrasonic testing methods in common use today. In phased array, multiple elements are used to steer, focus and scan beams with a single transducer assembly. The technology now is established and reliable, and codes have been developed supporting it. With this newer technique, greater flexibility and reduced inspection time can be realized, giving cost-effective benefits. Industries benefitting from this technology include power generation, petrochemical, pipelines, and structural fabrication.”

Adjournment