Back to Back Issues Page
PWL#067 - - Encyclopedia Online Volume 2, Hybrix Composite Panels, Welding Cobalt Filler Metal ...
March 02, 2009
We hope you will find this Letter interesting and useful.
Let us know what you think of it.

Encyclopedia Online Volume 2, Hybrix Composite Panels, Welding Cobalt Filler Metal, Welding Fume Trial, Low Pressure Cold Spray for WC-Co, Welding Cobalt, Roll Welding and more...

DON'T USE REPLY to send us your messages! Use Contact Us instead.

This publication brings to the readers practical answers to welding problems in an informal setting designed to be helpful and informative.
We actively seek feedback to make it ever more useful and up to date.
We encourage you to comment and to contribute your experience, if you think it may be useful to your fellow readers.
Click on Contact Us(opens new page).

You are urged to pass-along this publication to your friends, if you like it, and if you want to help them. If you received this from a friend and if you like what you read, please subscribe free of charge and you will also receive a bonus book on Practical HARDNESS TESTING Made Simple.
Click on Subscription (opens new page).

Note: References to articles or other documents are given here in one of two forms. If the links are "live" (usually underlined or otherwise highlighted) they are operated with a click of the mouse.

If they are URL's (Uniform Resource Locator), which is the analogue of an address, they begin with "http://..." or "www.". These are not live and must be copied and pasted entirely into the browser (after having been selected with the mouse or otherwise). If they are long they may be displayed in two or more lines. In that case one has to care that the URL be copied completely in a single line without any space, and Enter.

March 2009 - Practical Welding Letter - Issue No. 67


1 - Introduction

2 - Article - New Welding Resource

3 - How to do it well: Joining Hybrix

4 - Filler Metals for Welding Cobalt

5 - Online Press: recent Welding related Articles

6 - Terms and Definitions Reminder

7 - Article - Defendants Win California Welding Fume Trial

8 - Site Updating: Welding Cobalt, Roll Welding

9 - Short Items

10 - Explorations: beyond the Welder

11 - Contributions: Low Pressure Cold Spray

12 - Testimonials

13 - Correspondence: a few Comments

14 - Bulletin Board

1 - Introduction

This 67th issue of Practical Welding Letter opens with an Announcement and a Spring Offer... It is about a New book that I prepared, presenting a long list of useful links to competent Sources of Knowledge on the subject of Metals Welding.

The publications that you can reach, download and save, will form the Second Volume of the Encyclopedia Online (the First was presented two years ago), an easy and economical reference for your professional library.

You are invited to benefit of the introductory price, to profit of the discount available until the 15 of this Month. Hurry up, before the discount expires...

Then, following a question from a reader, we talk of a (relatively) new composite material. We think it is interesting, for the right applications.

Filler metals for Cobalt alloys have here a dedicated short note explaining uses and differences. Certain alloys are used especially for Hardfacing. References to Specifications may be useful to those needing them.

There is a Warning that young welders should take to their heart. Breathing welding fumes may compromise welders' health. The meager consolation of obtaining some money indemnity for the damages suffered seems not to be really achievable.

More and more the Courts free defendants from any responsibility in the cases they judge. A short reference to some news on this subject should ring alarm bells to attentive welders before it is too late, when there is still time to prevent the risk of damaging their own health. Be careful...

Our Website Update notice in Section 8 points to new pages published on Welding Cobalt and on Roll Welding. See details there.

Cold spraying is reaching new applications but it is not easy, when dealing with Tungsten Carbide particles for Hardfacing. A reported article explains the difficulties and the ways demonstrated to have achieved successful results.

The other departments can be found at their usual place. If you like what you read in this issue please let me know. If you want to contribute from your experience you are welcome. Enjoy your reading.

2 - Article - New Welding Resource: grab it now...

Almost two years after the publication of the first Volume of our Encyclopedia Online, dedicated to information on Metals and their Properties, and appreciated by many of our selected audience, I am glad to be proposing here to all readers the New Volume 2, dealing with Metals Welding.

As the first one, this volume presents a list of over 310 primary links, pointing to authoritative, instructive and valuable Internet sources that provide pages, brochures, leaflets, tables and other publications intended to enrich the knowledge of interested readers who care for their own advancement.

The opportunity of reaching easily and economically a vast amount of useful technological information represents a precious benefit for those who know how to use it to their advantage. It should not be dismissed carelessly. Knowledge and experience are irreplaceable foundations for every successful career and for inquisitive minds there is never enough.

It is the second best to the expensive alternative of purchasing Handbooks and dedicated Monographs, or to the not so convenient option of using the services of Libraries, that share the books with all in need to study them.

Here you will be able to study at home, at your leisure, directly from the screen of your computer or, if you prefer, from hardcopies you will decide to print, as much and as deep knowledge as you will want to dig out.

Once obtained the books, for enjoying at the most the opportunity of learning offered by the downloaded and stored information, readers should dedicate some time and thought to the organization of the cumulated materials in separate subfolders, to be named with meaningful titles.

One possible way to ease the retrieval of information when needed would be to assign in a separate file, to each page (or downloaded unit) a list of keywords. Each keyword should be linked to the title of the page and to the name of the subfolder. The comprehensive list of all keywords could then be sorted in alphabetic order, to permit quick location of the items sought.

The Books offered here are in pdf format, meaning that you would need the Adobe Acrobat software installed in your computer: if it is not yet there, you can download it free of charge from

A Preview of the Front Cover and of the Table of Content of the two Books can be viewed at
Preview 1: Materials - Volume 1 and
Preview 2: Metals Welding - Volume 2.

This exercise will prove to you that you will be able to download and to see onscreen the real products in a similar way.

You are urged to profit from the introductory price of only $ 20

To boost your professional knowledge you are invited to take this step. Consider that its content is much more valuable than the modest price it costs you.

Go to the new page of Metals Knowledge to get your Encyclopedia Online, Volume 1 and Volume 2.

3 - How to do it well: Joining Hybrix

Q: Writing M.Sc Thesis for SAAB Automobile AB in Sweden. Looking into a sandwich material called Hybrix to see if it can be used in an automobile body.

The sandwich material I'm investigating is made from thin facesheets (0.1 mm thick) of austenitic stainless steel. Arc weld studs are seemingly impossible to weld to this sandwich material due to the thin facesheets.

My question to you: are there any alternatives for welded studs? Maybe something that is more like a rivet or bolt.

PWL Note: I am glad of this opportunity to introduce to my readers a new material possibly not yet widely known. See the brochure:

A: You could try to use through passing rivets or bolts as per sheet
Tips for Processing.

But how will the joints behave under load?
Probably adhesive bonding, also mentioned in the above sheet, is likely to be more suitable, as it is used in aircraft and in car manufacturing. Even Laser welding is proposed there for joining, although without details.

I see that data on Bending Stiffness against Surface Density are reported, more important for crashworthiness properties than classic tensile testing data.

4 - Filler Metals for Welding Cobalt

As briefly outlined in our new page on Welding Cobalt, the preferred filler metals for welding selected Cobalt alloys are those with composition matching that of the base metal.

Those of current use, supplied as bare wire, are listed in the following
Table I, with the indication of nominal, approximate composition.
Readers should refer to the relevant specifications for the complete requirements.

Table I
Selected Cobalt Base Welding Alloys
Cobalt Alloys Composition %
Alloy AMS Co Cr Mo C Ni Si W Fe Other
HS25 5796 52 20 - 0.10 10 0.4 15 3 -
HS188 5801 39 22 - 0.10 22 0.06 14 3 1.25Mn, 0.07La

Note: For the alloy HS25, known also as L-605, Covered Electrodes of similar composition to that of bare welding wire, are available per SAE AMS 5797.

Cobalt base filler metals are supplied for hardfacing purposes. The types listed hereafter in Table II owe their wear resistance essentially to the carbides present in the weld deposit. The ductility of these alloys is limited.

Table II
Selected Cobalt Base Hardfacing Alloys
Cobalt Alloys Composition %
Alloy Standard Co Cr Mo C Ni Si W Fe Other
HS21* AMS 5819 62 27 5.5 0.3 2.5 1 0.5 2 -
Ultimet® R31233 54 26 5 0.06 9 0.3 2 3 0.8Mn
ERCoCr-A AWS5.21 Bal. 28 1 1.2 3 - 5 3 -
ERCoCr-B AWS5.21 Bal. 29 - 1.5 - - 8 - -
ERCoCr-C AWS5.21 Bal. 31 - 2.5 - - 13 - -

Note: * - HS21 is also known as ERCoCr-E per AWS A5.21

For welding of dissimilar metals, filler metals with higher ductility are generally preferred, mostly nickel based. A comprehensive table giving some indications on the suggested selection of possible filler metals for dissimilar joints can be seen at:

Welding Metal Filler Information

ANSI/AWS A5.13:2000
Specification for Surfacing Electrodes for Shielded Metal Arc Welding
American Welding Society / 07-Sep-2000 / 38 pages
Click to Order.

ANSI/AWS A5.21-2001
Composite Surfacing Welding Rods and Electrodes
American Welding Society, 01-Jan-2001, 41 pages
Click to Order.

Corrosion and Heat-Resistant, Welding Wire 52Co - 20Cr - 10Ni - 15W

Corrosion and Heat-Resistant, Covered Welding Electrodes 51.5Co - 20Cr - 10Ni - 15W

Corrosion and Heat-Resistant, Welding Wire 39Co - 22Cr - 22Ni - 14.5W - 0.07La

Corrosion and Heat-Resistant, Hardfacing Rod and Wire 62Co - 27Cr - 2.9Ni - 5.5Mo

5 - Online Press: recent Welding related Articles

Laser and waterjet: friends or foes?

The importance of exercising oxyfuel welding safety

Download Chapter 14 - Fatigue (23 pages) from
Elements of Metallurgy and Engineering Alloys
by F. C. Campbell

Size Matters (video)

Laser Welding: It’s Not Just for Metals Anymore

6 - Terms and Definitions Reminder

Agglomerated Flux for submerged arc welding is produced by baking a pelletized mixture of powders and binder and then crushing to obtain the required granular size.

Beam Divergence is the spreading of a beam's cross section with its distance from the source.

Carburizing Flame, also called reducing has an excess of fuel, resulting in a visible characteristic zone beyond the cone.

Dynamic Electrode Force is that exerted by the electrodes of resistance welders during the actual welding cycle.

Multipass Welding is a fusion weld produced with more than a single progression of the heat source and filler metal supply (if used) along the joint.

Upset Distance is the total reduction in the longitudinal length occurring in welding processes like friction welding, hot pressure welding and upset welding where an upsetting forging operation follows heat application.

Voltage Regulator is an automatic electrical control device that provides relatively constant voltage supply to sensitive users.

Wire Straightener is a multi roller device used to control cast and helix of coiled wire to ease precise supply to the feeder of a welding unit.

7 - Article - Defendants Win California Welding Fume Trial

"This defense verdict [...] demonstrates the overall lack of merit of these welding fume cases."

This sentence, from the following piece of news, caught my attention. See

The above statement is included in a note released by the attorney who assisted the defendants, employers of welders or manufacturers of welding electrodes.

I am not entering into the merit of the litigation. I would only like to stress that an interested lobby, called "The Welding Rod Litigation Network" comprised of current and former manufacturers and distributors of welding rods and others, stands behind its members, sued for damages to welders' health.

Young and enthusiastic welders investing all their skills in performing their work in the best possible way, should think first of all of their own health and of how will it be later on in their life.

If they dismiss the dangers of welding fume poisoning, it is all their fault. If they don't care, who should? Their life and that of their loved ones is on their own responsibility.

If their lungs are later on found ruined, it will be virtually impossible to demonstrate in court that the employer or the electrodes manufacturer have any liability for the cause of their condition. It will be too late to complain of their tragic doom.

Scores of learned research papers found "no association between exposure to manganese and Parkinson's disease". Also "no causal link exists between welding or exposure to welding fumes and an increased risk of Parkinson’s disease or any other similar neurodegenerative disorders."

These conclusions contradict the results of other research reported by OSHA and EPA. A short note with a few online references on the issue of Manganese fumes was published (2) in PWL#020.

Anyhow the harsh reality is that no hopes should be set on obtaining swift recognition of damages suffered from having breathed welding fumes.

  • Welders must learn all they can on the possible consequences on their health of breathing welding fumes.
  • They have to request that their employers install suitable fume extractors or give them adequate respirators.
    They should not be shy on the requests. Good welders are a precious commodity nowadays, not easily substituted for. If they are self employed they must invest in keeping their own health.
  • They must educate themselves to the self imposed discipline of using constantly the devices intended to reduce their exposure to welding fumes.

Litigations are good only for attorneys.

8 - Site Updating: Welding Cobalt, Roll Welding

One of the Pages of this Month deals with Welding Cobalt, a somewhat specialized niche reserved to High Temperature resistant or Corrosion resistant applications.

It would help to know that the mere contact with Copper could compromise any Cobalt welding job and that a few other precautions are required for successful performance.

The other page, on Roll Welding describes a process that is not for every shop. However knowing which are the typical applications that profit the most from this specialized process can open the mind to propose this process for new applications where its characteristics can be put successfully to use.

Find these new pages by clicking on Welding Cobalt and on Roll Welding.

To stay updated on new subjects as they are added to the Website, browse through the frequently revised Site Map or subscribe to our Welding Blog, showing both the new and the revised pages. See details under the NavBar, in the left column of every website ( page.

Let us have your comments! DON'T USE REPLY, click on Contact Us instead.

9 - Short Items

9.1 - Induction Welding produces coalescence of metals by the heat obtained from the resistance of the workpieces to the flow of induced high frequency welding current with or without the application of pressure. The primary high frequency inducing current is made to flow in specially designed inductors, generally in the forms of coils, around or near the workpiece, with no actual contact. The welding heat is concentrated at the desired location by the effect of the high-frequency welding current.

9.2 - Rolling Mills are machines used to reduce the thickness of metal stock and to produce certain desired shapes as the metal passes between rotating rolls mounted in a framework comprising a basic unit called a stand. Rolling generally also improves the mechanical properties of the rolled workpiece, especially in the long direction. Cylindrical rolls produce flat shapes; grooved rolls produce rounds, squares, and structural shapes

9.3 - Superplasticity is a state in which metals (most notably aluminum- and titanium-base alloys) or other solid crystalline materials are deformed well beyond their usual breaking point at elevated temperatures and under controlled rates of deformation.

9.4 - Trepanning is a metal working process with removal of chips, used either for producing a circular hole or groove, or for obtaining internal cores from solid stock. The cutting tool has either one ore more teeth revolving around a center.

9.5 - Wetting indicates the spreading, and sometimes absorption, of a fluid on or into a surface. In case of good wetting the interface tension between a liquid and a solid is such that the contact angle is very small. On clean surfaces a liquid filler metal or flux at high temperature spreads on and adheres to a solid base metal in a thin continuous layer.

9.6 - Yield Point is the first stress in a material at which strain increases without an increase in stress. Certain materials exhibit a localized transition from elastic to plastic deformation producing a yield point. If there is a decrease in stress after yielding, upper and lower yield points can be seen. The load at which the stress drops is called the upper yield point. The constant load shown on the stress-strain curve is the lower yield point.

10 - Explorations: beyond the Welder

New Smart Material Bends Under Internal Heat Source

Water Vortex Engineering

Examining a SLIce of the Arctic

Mars Research in Polar Bear Country
Polar Bear.

Cliffbot Goes Climbing

11 - Contributions: Low Pressure Cold Spray

The February 2009 issue of International Thermal Spray & Surface Engineering, the official Newsletter of the ASM Thermal Spray Society (an insert of AM&P Magazine) reports, among other news, on the "Low Pressure Cold Spraying of Tungsten Carbide Composite Coatings".

The research was conducted to improve the performance of Tungsten Carbide within Cobalt binder (WC-Co) thermal sprayed coatings, generally done by HVOF (high velocity oxyfuel). The limitations of this combination (process and coating material) are coating imperfections like cracks, blisters and/or delaminations and such effects as oxidation, decarburization, thermal expansion mismatch and undesirable metallurgical transformations.

The use of the cold spray process permits adhesion by solid state bonding of the particles, accelerated towards the substrate at supersonic speeds, without the negative consequences of thermal effects. The favorable results are obtained only at the right critical velocity for impact.

Although a fraction of the ceramic particles was found correctly dispersed in the metal matrix, the mechanical properties were not sufficient to provide adequate abrasion resistance. Therefore research was directed to test if the addition of a minimum volume percentage of ductile metals could help in improving results.

Simple mixing of powders was inadequate. Better results were obtained by coating the ceramic particles with aluminum or copper by a proprietary Chemical Vapor Deposition (CVD) process, thus demonstrating the feasibility of the proposed solution.

"The deposits fabricated from coated particles were characterized by a high percentage of well dispersed, retained carbide phase and low porosity. These characteristics yielded hardness values higher than equivalent deposits produced from traditional metal-ceramic blends".

Interested readers are urged to seek the original publication indicated above.

12 - Testimonials

From: Jim Diamond
To: Welding Advisers
Date: 02 Feb 2009, 10:18:44 AM
Subject: Re: PWL#066 - Weld Failures, Distortion, GMAW filler for AHSS [...]

Thanks so much for the news letter, it has information that you can use everyday.

I wish all suppliers could/would read the articles, it would sure solve lots of everyday problems.


Jim Diamond

Name: Mike Corcoran
E-mail Address: removed for security
Country: United States
Introduce Your Organization: AMT Inc.
Describe Your Responsibility: Shipping/Q.C. supervisor; company production & repair welder.
Questions and Feedback :


I've been here before, I think you have a real good thing going here. I figured out my previous problem. Thank-you.[...]

Thank-you again. Keep up the good work, I'm sure that I'm not the only one that appreciates it.

13 - Correspondence: a few Comments

13.1 - It is quite interesting to receive e-mail messages with a collection of different questions from the whole world over. I look at them with interest and curiosity although I am sometimes surprised by the fact that some of them declare the complete incompetence of those asking them.

That is why I would appreciate if the inquirers spent a short time trying to clarify their request first to themselves, before they attempt to ask me. I am confident that only then can my answer be more pertinent and useful.

The suggested steps are written on the top of our Contact Us page and should be useful to clarify any issue and to decide if there is need to send me an immediate question.

Browsing through Site Map, Welding Topics, Weld FAQ pages and finally running a Google Search of my Website will help locate possible answers. This procedure should give quite a good indication of whether the subject is treated somewhere in the website or in the collection of Practical Welding Letters.

13.2 - I should apologize with a reader who asked me a long time ago a question on Gas Metal Arc Brazing. Unfortunately the question and my inadequate answer are submerged in the large heap of correspondence so that I cannot single it out.

At that time I was convinced that there is no such thing. It had to be either Welding or Braze-Welding. Or could it be Brazing by any of the known processes. That is what I answered.

Now I know that, although the process cannot be called Brazing, according to the accepted definition, nevertheless Braze-Welding can be performed with the equipment and techniques normally used for GMAW but with different filler metal.

I am sorry that I was probably somewhat harsh in my answer, where I should have investigated the matter deeper and qualified my response with more patience and details.

14 - Bulletin Board

14.1 - Heat Treating of Light Alloys
March 25-26, 2009 - Doubletree Hotel Anaheim/Orange County, Calif.

14.2 - MATERIALS 2009 - 5th International Materials Symposium
5 - 8 April, 2009 - Lisbon, Portugal

14.3 - If the global economic crisis risks to hit yourself or someone near you, see how you can
Create your job.

Important Announcement

See our New Page on Metals Knowledge.
New Volume 2 available on Metals Welding, besides Volume 1 on Materials.
Reach Online the best Expert Sources for assembling at no cost your Metals Encyclopedia , a rich collection of valuable information. You can!

Click on the following image to watch the SBI! TV Show!



Build It!

Click on this Logo NOW!

Copyright (©) 2009, by Elia E. Levi and
All Rights Reserved

See you next time...

Back to Back Issues Page