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PWL#166, Welding Pipe Downhill, Sinter Brazing, New Brazing Alloys, Prevent Defects in Alum Welding
June 01, 2017
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Practical Welding Letter No. 166
June 2017

PWL#166, Manual Shielded Metal Arc Welding (SMAW) of Pipe Downhill, Sinter Brazing by unifying sintering and brazing in the same heat cycle, New Brazing Filler Metal Alloys, summaries of research papers presented at the 11th International Conference on Brazing, How to Prevent Defects in arc welded Aluminum, Laser Shot Peening, Advanced Instrumentation for Putting Welds to the Test, Study to Find the Truth and much more...

June 2017 - Practical Welding Letter - Issue No.166

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This publication brings to the readers practical answers to welding problems in an informal setting designed to be helpful and informative.
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1 - Introduction

2 - Article - Welding Pipe Downhill

3 - How to do it well: Sinter Brazing

4 - Brazing Filler Metal Alloys

5 - Online Press: recent Welding related Articles

6 - Terms and Definitions Reminder

7 - Article: How to Prevent Defects in arc welded Aluminum

8 - Site Updating: Laser Shot Peening

9 - Short Items

10 - Explorations: beyond the Welder

11 - Contributions: Putting Welds to the Test

12 - Testimonials

13 - Correspondence: a Study to Find THE TRUTH

14 - Bulletin Board

1 - Introduction

This time the opening article (2) of this 166th Issue deals with a most basic Shielded Metal Arc welding (SMAW) technique, that of welding pipes downhill: the summarized original article was written by instructors whose job is exactly to prepare and certify new welders to weld pipelines.

Therefore the article is highly informative and helpful: interested readers can profit to learn details by seeking the original as indicated.

The next article reviewed (3) reminds that a practical way exists to braze together powder metallurgy preforms while the same heating cycle promotes both sintering and brazing. But most attention must be devoted to optimize all parameters in order to produce quality assemblies.

What follows (4) is the a list of the titles of summaries of brazing research papers from a recent international conference. The summaries can be found in the referenced pages. Interested readers can check if some of the specific subjects dealt with there have any relationship with their problems.

The article reported after that (7) helps to look for conditions impairing the quality of welded aluminum parts.

For the website update (8) we took the hint from a recent article to revise an existing page, by focusing on an advanced process called pulsed laser shot peening, which is presently employed only for expensive high performance aerospace parts, although many industrial items could improve their fatigue life by being treated this way.

Then (11) we report an interview from another magazine discussing the contribution of modern analytical equipment in the search for hidden problems in the metallurgical makeup of welded joints, that could translate in failure later in the operational life of weldments. Too sophisticated for everyday items, the scientific approach is certainly required for advanced applications.

Finally (13) we report on an extended investigation performed by the company who helped us to build our website, to expose the improper behavior of a competitor who procured remarkable damage to large droves of unsuspecting victims and could have damaged also the company we follow for their unfailing helpfulness.

Even if not applicable to most of our readers, the results may illustrate the many faces of fraud likely to show up from anywhere, just a reminder to stay always on the alert.

The other columns appear where they do so usually. As always we hope that at least some of the published subjects might interest as many readers as possible: your feedback, comment and original contribution are always welcome. Please use the Contact Us Form.

2 - Article - Welding Pipe Downhill

Weld. Jnl. Cover May 2017

The May 2017 issue of the Welding Journal runs at page 90 an interesting article full of practical hints for those welders whose job is to weld pipes.

It deals in particular with field welding API 5L line pipe in grades X42 or X52, where many welding procedures, for thin wall pipes 0.5 in. or less, require downhill shielded metal arc welding (SMAW) using covered electrodes of cellulosic type EXX10.

The article reminds that this particular electrode cover permits to run "hot and fast" downhill welding with higher productivity relative to alternatives, using direct current electrode positive (DCEP) with higher voltage than required by other electrodes.

New inverter power sources are available with special control knobs for optimizing cellulosic operating mode.

The article specifies a few setup data required for downhill pipe welding: interested readers should seek the original, because summarizing the recommendations would deprive the exposition of essential information. Criteria are given for the selection of bevel, root opening and electrode size. Tack welds size, position and preparation are recommended.

Then specific hints are given for selecting amperage, electrode orientation and drag angle. Further indications are given to manage the "keyhole", essential for assuring complete penetration.

Additional explanations and "how-to" instructions are also given to instruct welders on the best way to deposit fill and cap passes. The final recommendation is, quite obviously, to practice as much as needed.

The original article is recommended reading for all, and specially for involved new welders.

properly sized keyhole

On a root pass with a properly sized keyhole, very little light appears on the outside of the pipe, as the arc force pushes the weld metal through to reinforce the backside of the joint.

[From the Welding Journal May 2017 - page 93]

3 - How to do it well: Sinter Brazing

Weld. Jnl. Cover May 2017

Among the various fabricating techniques used to build components for different industries, the Sinter Brazing process offers an interesting way to produce complex assemblies by unifying sintering and brazing in the same furnace heating cycle.

An article on the fundamentals of this process was published at page 44 in the May 2017 issue of the Welding Journal.

Success can be assured only if the severe criteria of surface cleanliness from contaminants and suitable clearences are respected. Oxides should be completely reduced before brazing filler metal can flow and wet the surfaces to be joined. An important factor is the required equilibrium dew point at the brazing temperature.

Densities of the green preforms must be so compact that porosity will not absorb an eccessive part of the brazing alloy, depriving the joint of the filler. Flux is sometime used to reduce oxides, if found necessary.

Interested readers are urged to seek the original article. Experienced readers who may have comments to add are invited to contribute them here.

Sinter Braze

Lower density powder metal compacts pull more fillermetal from the joint clearance than the higher density compact of the same material.
This is shown by the deposits on the tops of the sintered compacts, as well as the volume of filler metal shown in the sectioned and etched samples.

[From the Welding Journal May 2017 - page 46]

4 - Brazing Filler Metal Alloys

Weld. Jnl. Cover May 2017

The Brazing and Soldering Today supplement, published in the May 2017 issue of the Welding Journal at pages 52-56 provides information on the following items:

  • Active Soldering Ceramic-Ceramic and Ceramic-Metal Compounds
  • The Microstructure of Li-Ti Ferrite Joints by Brazing with a Bismuthate Glass Solder
  • Effect of Ag-Cu-Ti Braze Preform Thickness on the Properties of Alumina-to-Alumina Joints
  • Corrosion Protection of Small-Diameter Steel Pipes by Soldered-Clad Layers
  • Development of Cu-Al-Ti Filler Metals for Al2O3/SS Brazed Joints
  • Brazing Kovar to Alumina and LTCC for Integrating Ceramic Pressure Sensors
  • Reactive Brazing of Magnesium-Steel Contact Using Pure Nickel as the Interlayer
  • Application of Electrical Resistance Measurement for Quality Assurance
  • Grain Boundary Penetration of a Pure Copper Brazed Joint
  • Boron and Phosphor Effects in Nickel-Based Brazing Alloys on Different Base Materials
  • Microstructure and Mechanical Properties of Ti3Al/Ni-Based Superalloy Joints
  • Evaluation of DCB and V-Notch Fracture Mechanics Test Methods for High-Temperature Brazed Joints of Gas Turbines
  • In-Situ Synthesis of Difficult-to-Form Ag-Cu-Zn Brazing Filler Metals
  • Rapid Solidified Al-Si-Cu and Al-Si-Ge Brazing Filler Metals for Joining Aluminum Alloys
  • Low-Temperature Soldering Premetallized Glass to Steel and Properties of Joints
  • Economic Processing of High-Volume Binder Burn Out in the Vacuum Furnace

A list of 16 bibliographic References to the Sources is reported.

In the above pages are reported summaries of research papers presented at the 11th International Conference on Brazing and Diffusion Bonding, held on June 2016 at Aachen, Germany.

5 - Online Press: recent Welding related Articles

German Research Institute Uses VSHAPER ONE Pro 3D Printer to Study and Analyze Metal-Polymer Hybrid Structures

Impact of Arc Welding Technology on Consumption of Welding Consumables welding-technology-on-consumption-of-welding-consumables/

SABIC and Airborne Join Forces to Develop Automated Composites Processes

Welding Dissimilar Metals for New Product Designs

Cyan Tec to deliver laser welding system to Nuclear Advanced Manufacturing Research Centre

6 - Terms and Definitions Reminder

Abrasive Waterjet Machining is a cutting process using a high speed water jet with or without abrasive particles to produce cuts into solid metals, ceramic, glass and composite materials.

Brittleness is the tendency of a material to fracture without prior noticeable plastic deformation. A brittle fracture may be not an intrinsic property, but due to stressing conditions (i. e. low temperature).

Cavitation is the formation of vapour cavities in a liquid that are the consequence of forces acting upon the liquid.

Dew point is the temperature to which air must be cooled to become saturated with water vapor.

Eddy-current testing is one of many electromagnetic testing methods used in nondestructive testing (NDT) making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.

Faying Surface is one of the mating surfaces that are in contact at a joint.

Gas welding is a nonstandard term for oxy-fuel gas welding.

Heat affected zone crack is a crack occurring in the heat affected zone.

7 - Article: How to Prevent Defects in Arc welded Aluminum

Weld. Jnl. Cover May 2017

Confronted with more severe requirements in nondestructive radiographic and ultrasonic testing of aluminum welded structures, a shipbuilder had to eliminate all sources of unwanted hydrogen that could have found their way in aluminum weldments, producing unacceptable porosity.

Systematic searching for the causes of inferior quality and for the needed improvements brought about a check list of items and of recommendations, then organized in an article published in the May 2017 issue of the Welding Journal at page 96.

Detailed warnings were formulated and supplied to all welders involved, to avoid all contaminants. Besides eliminating moisture, water and lubricants, instruction were given to use only electric tools, because the exhausts of pneumatic ones may contain moisture or lubricants and contaminate joints to be welded.

Coiled filler metals must be kept in their original package, to be removed only when used. Moisture should not be permitted to condense on cool wire surfaces.

Welding equipment with plastic liners must be dedicated to aluminum only to avoid contamination. Shielding gas must be dry, of suitable flow and dew point. A few more recommendations are spelled out.

A table describing possible causes of porosity is included in the article for guidance. Finally a list of good practices explains how to perform grinding for exposing incomplete penetration. Attention to the highlighted details should improve performance to acceptable non destructive test results.

Interested readers are urged to seek the original article summarized here.

GMAW of an aluminum aircraft elevator

Mechanized GMAW of an aluminum aircraft elevator for the USS Gerald R. Ford.
(Photo courtesy of Chris Oxley, Newport News Shipbuilding.)

[From the Welding Journal May 2017 - page 96]

8 - Site Updating: Laser Shot Peening

Weld. Jnl. Cover May 2017

Following the suggestion of an article published at page 38 in the May 2017 issue of the Welding Journal, a revised section summarizing the characteristics and the benefits of the process mentioned in the title above, was merged into the page on Shot Peening appearing since a long time in our website.

The article above traces a short history of the development of laser shot peening, which lasted for some decades, starting around 1960 with the development of the first pulsed lasers.

By pulsing laser beams on the surface of materials suitably protected, high pressure plasma is generated, inducing layers of residual compressive stresses deeper than standard shot peening (which shoots hard particles made of metal, glass, or ceramic at the surface of the material undergoing treatment).

The presence of compressive stresses has the remarkable effects of resisting cyclic loading that produces fatigue failures, and also of slowing down crack growth.

The article reviews the behavior of different materials treated by laser shot peening and reports some of the published results of research: it remarks that additional testing is required to complete a better understanding of the benefits to be gained by LSP.

Selected sensitive parts of aircraft engines and generally high-cost and high-importance applications are currently processed by this technique because of their documented longer fatigue life in regular operation.

But, the article concludes, the ability to reliably increase the strength of weldments by inducing compressive stresses can benefit in the future the entire welding industry.

The above website page can be found at

Readers are urged to send us comments and feedback, or original contributions originating from experience and practice with welding related techniques using the Contact Us Form.

Laser Shot Peening

LSP drawing detailing the laser pulse, opaque and transparent layers, and plasma cloud.
(Image courtesy of Professor Michael Hill.)

[From the Welding Journal May 2017 - page 39]

9 - Short Items

Do You Know...

    ...Stronger web?
    See: ceramics?
    See: ethz.


    ...thinnest mirrors?
    See: nasa.

    ...resilient enamel?
    See: umich.

9.1 - Salt Bath Heat Treatment for metals is carried out in a bath of molten salt.

9.2 - Tempering, in heat treatment, means reheating hardened steel or hardened cast iron to some temperature below the eutectoid temperature, for the purpose of decreasing hardness and increasing toughness. The process also is sometimes applied to normalized steel.

9.3 - Ultimate Elongation of a tensile specimen is the elongation measured at rupture.

9.4 - Vacancy is a structural imperfection in which an individual atom site is temporarily unoccupied.

9.5 - Water Quenching is a quench in which water is the quenching medium. The major disadvantage of water quenching is its poor efficiency at the beginning or hot stage of the quenching process.

9.6 - X-ray Spectrometry is the measurement of wavelengths of x-rays by observing their diffraction by crystals of known lattice spacing.

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10 - Explorations: beyond the Welder

The Human Nose Knows More Than We Think

Climate Change Is Turning Antarctica Green

What Are Software Vulnerabilities, and Why Are There So Many of Them?

Trump Budget Would Slash Science Programs across Government

Bizarre Star Dims Again, and Astronomers Scramble to Catch It in the Act

11 - Contributions: Putting Welds to the Test

AMP Cover May 2017

An article under the above title was published at page 30 in the April 2017 issue of Advanced Materials and Processes (AM&P), a publication of ASM International.

In the interview, the editor asked the product manager of a manufacturer of advanced instrumentation, what can be done to alert welded components builders of impending failures causes hidden in the products they make.

The first answer was that industry as a whole is investing heavily in developing analytical instrumentation technology and test procedures that more directly and reliably expose root causes of failures.

In the case of metal welds, manufacturers now have access to powerful imaging techniques such as electron backscatter diffraction (EBSD), meaning they just need to put a weld sample under a scanning electron microscope and look for telltale microstructural changes.

To make advanced weld testing more accessible to the industry one needs improved cooperation between academy and industry to teach the latter how to profit from the use of modern analytical tools and how to implement best practices for weld test procedures.

Efforts are being done in this direction and productive cooperation is bound to reach tangible results. Interested readers are invited to seek the original article that can put them in contact with the scientist of the instrument producer, possibly capable to address them to the solution of problems they may have.

electron backscatter diffraction

EBSD Euler maps reveal microstructural changes in aluminum caused by welding.
Note the differences in grain size and orientation between
(a) the bulk material and (b) that in the weld region.

[From AM&P April 2017 - page 30]

12 - Testimonials

On Wed May 10 14:19:40 2017, the following results were submitted from the "Form 5" on

Name: Jim Warren
E-Mail Address: removed for security
Country: United States
Your Task: Tube Steel tearing
Details: [...]
Thanks in advance, for your consideration and any guidance you can provide.

13 - Correspondence: a few Comments

As our attentive readers may know, we have been using for quite a long time a friendly tool to build and expand our website ( The friendly tool is called Site Build It (SBI for short) and it provides all services that a person should use to build an attractive website to inform, entertain and satisfy readers on the particular topic (niche) selected.

This is particularly important to anyone having no previous computer or website experience, but it is much more than that. We add generally a few links for interested readers to easily access this very rich source of instruction and encouragement, which includes lessons on how to do it.

Many examples are available, concerning successful entrepreneurs who reached their goals by building a business of exploiting their particular interest. Site Build It is proud of the success enjoyed by the persons it helped to overcome all sorts of difficulties on the way to a rewarding life of satisfactory achievements.

Lately though they got notice of an unscrupulous competitor who entices its followers to steer away from SBI by promising success along a faulty route to nowhere.

It appears that a company called Wealthy Affiliate ("WA") has been misleading folks who search for reviews about Solo Build It!. Its affiliates post "fake reviews" that rank high at Google.

The affiliates mislead people into believing they're reading a review (i.e., a fair and balanced review, followed by a recommendation).

They have actually entered a sales funnel for WA -- whatever the content may be (usually some rehash of inaccurate material), affiliates recommend WA as #1.

SBI reaction was to Conduct a Study to Find THE TRUTH.

Link to Part 1 of the Study: Intro & Summary: Fake Reviews vs. A Peek at the Truth:

Link to Part 2 of The Study: Objective, Rigorous, Statistically Significant, and Reproducible:

Link to Part 3 of the Study: The Results:

Even a cursory review of the Study easily reveals that the purpose of Wealthy Affiliate is to induce readers to believe in fake revues, to embark in the useless exercise of writing more of the same, and to recommend WA without any proven reference of their claimed "best" status, in preference to SBI, despite their solid demonstrations on the effectiveness of their philosophy and longtime history of honest deeds.

We urge our readers to keep clear of WA and, if they want to explore how to build a honest business by investing their time and mind in building a successful internet business, to trust SBI as a faithful hand ready and willing to help them out.


14 - Bulletin Board

14.1 - National Robotic Arc Welding Conference and Exhibition.
June 6, 7. Milwaukee, Wis

14.2 - Additive Manufacturing with Powder Metallurgy.
June 13–15. Bellagio Hotel, Las Vegas, Nev.

14.3 - 70th IIW Annual Assembly and International Conference.
June 25–30. Shanghai International Convention Center, Shanghai, China.

See you next time...

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