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PWL#089 & 089B - Welding Standards, Aluminum weldability, Cast Iron-steel welding, DS Al Alloys,Lean January 03, 2011 |
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| We hope you will find this Letter interesting and useful. Let us know what you think of it. PWL#089 - European Welding Fabrication Standards, How to find if an aluminum alloy is weldable, welding cast iron to alloy steel, Dispersion Strengthened Aluminum Alloys, Applying Lean Principles to Combat Waste, Welding production planning, Fractographic Examination and much more...
and Mid January Bulletin
DON'T USE REPLY to send us your messages! Use Contact Us instead. Please be advised that the Mid Month Bulletin is now integral with the regular PWL publication. You will find it further down, past the end of this Practical Welding Letter. Important AnnouncementFor assembling at no cost your own Encyclopedia Online, A New Opportunity!By promoting these books above you can gain up to 75% of the sale price. Interested? Please explore the ClickBank process at:
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1 - Introduction 2 - Article - European Welding Fabrication Standards 3 - How to do it well: Find if an aluminum alloy is weldable or not 4 - Filler Metals: welding cast iron to alloy steel 5 - Online Press: recent Welding related Articles 6 - Terms and Definitions Reminder 7 - Article - Dispersion Strengthened Aluminum Alloys 8 - Site Updating: Welding-planning, Fractographic Examination 9 - Short Items 10 - Explorations: beyond the Welder 11 - Contributions: Applying Lean Principles to Combat Waste 12 - Testimonials 13 - Correspondence: a few Comments 14 - Bulletin Board 1 - Introduction Practical Welding Letter wishes to all readers and their families a Happy and Prosperous New Year in Good Health and Happiness. This 89th issue of Practical Welding Letter for January 2011 opens with the review of a downloadable document likely to shed light on how to comply with welding standards. Although it is meant to be relevant to those bound to European Standards, it provides an overview suitable for any person interested in understanding general qualification requirements. Therefore I recommend reading the publication and keeping it available for reference. Then, following a query that asked how to find out if a given aluminum alloy is weldable or not, a note reminds the types of aluminum alloys and suggests to perform qualitative analysis if its commercial or standard designation are not known. Also the subject for the filler metals section was offered by a query for a consumable to be used for welding together cast iron and alloy steel. Two observation are included in the answer. First, that the materials are not sufficiently identified and second that, if the steel is indeed in the form of hardened and tempered fasteners, their strength will be inexorably compromised by weld heating. The article in section 7 introduces Dispersion Strengthened Aluminum Alloys, manufactured by special procedures (Rapid solidification and Powder Metallurgy). To the same subject are devoted the resource links presented in the Mid Month Bulletin, the section appended at the end of this publication. The Pages of the Month added to the website deal as usual with two unrelated subjects. The first is concerned with an organizational program for planning the production of items where welding is needed. It should be appreciated that the economic results of the operation will depend deeply on how good and realistic the plan is and on how well it is implemented. That is why utmost attention should be devoted to this subject. The second page explains what to look for in a fracture to glean the hints of the main cause of the failure. A lot of information is there for those who know how to recognize the signs. While waiting for some expert invited to investigate, one should at least preserve the fracture surfaces as they were at the time of the event. In the contribution section 11, continuing the theme exposed in an article of last issue and referring to a Welding Journal Article, more suggestions are given on how to look for eliminating the wastes that affect most of not yet optimized welding operations. The other departments can be readily found at their regular place. Enjoy your reading and let us have your feedback and comments using the Contact Us Form. The references to online resources, assembled in this issue for the Mid Month Bulletin, that follows the regular issue, are devoted to Dispersion Strengthened Aluminum Alloys, the subject of the article in section 7 further down, as already mentioned above. 2 - Article - European Welding Fabrication Standards An interesting publication (*) has recently caught my attention. It was designed as an aid to continuing education of professionals employed in welding activities. It is meant to provide information on European standards relevant to welding fabrication as part of a larger educational effort in welding related disciplines. Considering the good quality and the relevance of the information also to those not specifically bound to use European standards, this note presents the publication, deemed useful for clarifying information and concepts. Besides providing clear reference to European Standards connected to welding operations, this publication introduces concepts and practices universally applied for assuring the safety of metallic constructions. It is first reminded that ISO 9001 standard has been developed in order to apply a consistent Quality Management System throughout industry at large. However, for those fabrications where quality cannot be established only by inspection of the finished product, then quality management alone is insufficient to assure that special processes have been carried out correctly. Specific European Standards are introduced and expounded to show how manufacturers should comply with general and specific requirements. In particular, the use and application of EN ISO 3834 is explained. It is a standard independent of the type of construction manufactured, that provides a method to demonstrate the capability of a Manufacturer to make products of the specified quality. Then the five parts into which is structured the above standard are introduced, with explanations relative to the different levels of quality requirements applicable to different structures depending on how critical they are with respect to safety. Certification to the above standard is shown to be articulated in national organizations, assessed and monitored against constant rules, to ensure that manufacturers are competent and exercise adequate control of the special processes of welding so that customers or others may have confidence that the welded products they produce will comply with the regulatory and/or contractual requirements. The European Federation for Welding, Joining and Cutting (EWF) certified companies will have demonstrated that they have achieved an identified, minimum level of capability over a specified scope of activity, irrespective of the country in which they had been qualified. The comprehensive EWF Integrated Manufacturer Certification System (EWF IMCS), covers all the management aspects in welding fabrication, including quality, environment and heath & safety. The publication lists and reviews the requirements that Manufacturers and Subcontractors (managed by Manufacturers) must meet, after demonstrating technical competence and adequacy of resources. Welders must be qualified. A special section is dedicated to the introduction of the tasks performed by welding coordinators, personnel with considerable knowledge and expertise, responsible for all quality activities. Inspectors must be qualified according to specific requirements. Equipment properly maintained must be validated, with all instruments currently calibrated. Production plans must be ready before starting production and specific instructions (Welding Procedure Specification - WPS) must be ready for all welding processes employed. Identification, Traceability and acceptable Quality records must be assured. Then overviews of standards are provided for applications involving:
Summing up, this is recommended reading for all involved in welded metal fabrication. The publication can be Downloaded from the following URL. (*) - Welding Fabrication Standards (95 pages) 3 - How to do it well: Find if an aluminum alloy is weldable or not Good that you asked. It is better to pause and to inquire to get the answer before welding, otherwise one may make irreversible damage to whatever was incautiously welded. Weldable is to be understood by fusion welding, that is by processes that use an electric arc or a flame to cause melting of the alloy. Aluminum alloys are also classified as being or not Heat Treatable by Solutioning and Precipitation Hardening. For those alloys that are both heat treatable and weldable like 6061 and similar alloys, additional heat treatment may be needed to restore mechanical properties after welding. Heat treatable high strength aluminum alloys like 2024 and 7075 which are not successfully welded by fusion welding, are currently welded by resistance spot welding. One should know which is the material one wants to weld. In case the material is new and identified by a standard designation, it is easy to find in handbooks or from the supplier its welding characteristics. If you consider repairing an aluminum object whose designation you ignore, first look on it to see if it shows signs of original welding. If it was welded it is weldable. If it has only spot or seam resistance welds, it is probably not fusion weldable. If the original material is not known, the family to which it belongs should be determined at least by qualitative analysis, preferably by X-ray fluorescence methods. See Material Identification. Hardness testing should also be performed to determine the material condition. See also:
Aluminum Welding Please be advised that special aluminum alloys, called Metal Matrix Composites, including reinforcing particles of various types are not considered weldable by common means. See Joining Aluminum MMC. Also a different class of aluminum base materials for moderately elevated temperatures, called Dispersion Strengthened Aluminum Alloys and introduced further down in Section 7 in this issue of PWL, are not considered weldable unless special procedures are developed and applied. To the same subjects are devoted the links presented in the Mid Month Bulletin, the section appended at the end of this publication. 4 - Filler Metals: welding cast iron to alloy steel A few queries were submitted asking for the consumables needed for welding cast iron to alloy steel. More specific queries asked the same but the cast iron was specified as (Indian Standard) IS 2644 Gr. 2 and the alloy steel was indicated as IS 1367. Unfortunately, while the inquirer had in mind a very specific application, the indication of IS 1367 leaves the material undefined. In fact to the best of our understanding, this specification refers to technical supply conditions of Threaded Fasteners from different materials. From a publication available online on Threaded Fasteners For such elevated Strength levels, welding could be possible only with very specific procedures, including preheat and post weld heat treatment, depending on the application and its requirements. Without that, the risk of cracking is quite real, and even if cracks are avoided, then the strength is drastically reduced. Regarding the Casting, Indian Standard IS 2644 : 1994 The Mechanical Properties of Grade 2 Designated CS 700 are as follows While these requirements are not exceptionally high, any welding process applying heat will affect the mechanical properties obtained by Hardening and Tempering Heat Treatment. These consequences should be understood by those specifying the welding, who in this query seem to be interested only in the consumables, without a thought on the effects of welding heat. In the page Interested readers could get some useful information from that article. What is important to retain from the present note is that, when facing a question like the one of the title, there is more to the solution of the problem than the definition of a suitable consumable. The fabrication or the repair of a cast iron (or steel) part or joining to that an alloy steel item should be viewed as an engineering project to be addressed seriously and completely. 5 - Online Press: recent Welding related Articles Worldwide Fastest X-Ray Video of a Laser Welding Process Friction Stir Welding of ODS (Oxide Dispersion Strengthened) Steels Tackling aluminum GMAW Flux-Cored Welding: The Basics for Mild Steel Connect - Issue 169 November/December 2010 6 - Terms and Definitions Reminder Coefficient of Thermal Expansion (CTE) is the unit change in linear dimension of a body when its temperature is changed by one degree. Off Time in resistance welding defines the time during which the electrodes are off the workpieces, used for repetitive welding cycles. Parallel Welding in resistance welding is a variation in which the secondary current is divided in parallel electrical paths, typically with both electrodes from one side of the part, held by an anvil from the other side. Rockwell Hardness Test measures the residual penetration depth of an indenter (a hardened steel ball or a diamond cone) after a specified sequence of load application and removal. Soldering is a group of joining processes where parts are heated (by various means) to a suitable temperature not affecting the base metals and by wetting the surfaces with a filler metal whose liquidus does not exceed 450 0C (840 0F). Ultrasonic Examination is a non destructive test using beams of high frequency sound waves that are introduced in a test object to detect and locate surface and internal discontinuities. Visual Inspection procedures establish which characteristics must be examined before, during and after welding to avoid unacceptable features and to assure conformance to requirements. Welding Transformer is used to supply electric current suitable for welding. 7 - Article - Dispersion Strengthened Aluminum Alloys The elevated mechanical properties exhibited by heat treatable aluminum alloy derive from the finely divided precipitation particles generated when the alloys of selected compositions are subjected to solutioning and aging thermal processes. Unfortunately the exceptional properties shown at room temperature are lost when the structures made of these materials are heated to moderate temperatures. The reason is that heating causes coarsening and precipitation of those particles responsible for the sought mechanical properties. In order to develop alloys capable to reduce the damaging effect of heat, particles resisting coarsening and dissolution were produced, to be integrated with processing procedures avoiding melting. Powder Metallurgy (P/M) and Rapid Solidification (RS) together with mechanical alloying, were found to be promising routes for the production of primary semifinished shapes of the advanced alloys. These are the Dispersion Strengthened aluminum alloys, containing a fine distribution of oxides, oxynitrides and/or carbides in a fine grained alpha aluminum matrix. At room temperature their properties cannot compete with the strongest of the conventional heat treated alloys, but at higher temperatures they show only minimal decrease in their properties. The particulates to be distributed into the matrix are selected among the most promising of those obtained by alloying with elements assuring low solid solubility and low solid state diffusivity in alpha aluminum. Rapid solidification of aluminum alloys, containing iron (Fe) as a major constituent at 8-12% but also ternary and quaternary precise additions of one or more from the elements molybdenum, nickel, cerium, vanadium and silicon, produce particulates of refined metastable microstructures. The thermomechanical processing which follows produces consolidated products consisting of very fine size dispersoid particles in an equally fine grain size alpha aluminum matrix. The particles provide exceptional thermal stability and excellent mechanical properties from room temperature up to 345 0C (650 0F). The volume fraction of the dispersoid particulates in representative alloys may range from 15 to 35%. Fusion welding applied to these materials causes profound modifications of the original microstructure and affects severely the resulting mechanical properties. Nevertheless, by thorough development work implementing exceptional controls and by limiting heat input, acceptable results may be achieved. A short account of the above problems is available in my page on Joining Aluminum MMC. The Mid Month Bulletin attached to this issue of PWL, and appearing past the end of the regular publication, is devoted to presenting online links to resources on the subject of Dispersion Strengthening of Aluminum Alloys. Readers are urged to download as many of the publications as they may wish, and to save them in suitable folders identifiable by meaningful names. 8 - Site Updating: Welding-planning, Fractographic Examination This time the Pages of this Month refer as usual to two unrelated subjects. While industrial Production Planning for machining operations is quite an understood and well mastered subject that permits to prepare precise production plans and to follow them quite accurately, when welding processes are involved many managers don't know how to deal with them and let the people on the floor do what they know at the best of their capability and good will. This attitude is regrettable of course, but it is unavoidable unless a good welding engineer is put in charge of managing all welding operations. Those who decide that it is preferable to spare the cost of keeping such a professional in house ignore that they spend many time that amount in unrecoverable waste. The influence of this policy on the bottom line of the company escapes from them. The first Page of this Month is dedicated to production planning of welding operations and it tries to explain all the factors involved in successful managing of welding production. It is found by clicking on Welding Planning. The study, the description and the interpretation of the minute signs that characterize the fractured surface of a failed body is called Fractography. To the knowledgeable person these signs hint at the cause of the failure. When additional information is obtained, the total picture becomes often sufficiently clear so that corrective actions can be implemented to avoid the recurrence of a similar event. The second Page of this Month is a short introduction to this subject, available by clicking on
Fractographic Examination To remain updated as new pages are regularly added to the website, please subscribe to the RSS (follow instructions under the NavBar in each page), look at the Site Map, or review periodically the Welding Blog. You are urged to inform your friends of this website: they may benefit from the quite extensive information available to all readers and can ask questions that may help them. 9 - Short Items 9.1 - Surface Texture is the roughness, waviness, lay (the direction of predominant surface pattern remaining after cutting, grinding, lapping, or other processing) and flaws associated with a surface. 9.2 - Triaxial Stress is a state of stress in which none of the three principal stresses is zero. 9.3 - Unit Cell is a repeating unit of the space lattice, an infinite three dimensional array of points describing completely the structure of a perfect crystal. 9.4 - Work Hardening (same as strain hardening) represents an increase in hardness and strength (with reduction of ductility) of metals caused by plastic deformation at temperatures below the recrystallization range. 9.5 - X-Ray is a penetrating ionizing electromagnetic radiation, usually generated by accelerating electrons to high velocity and suddenly stopping them by collision with a solid body. 9.6 - Young's Modulus is the same as modulus of elasticity or the ratio of tensile or compressive stresses to the resulting strain. 10 - Explorations: beyond the Welder X-rays From Lightning Photographed Ten more science stunts for Christmas World's Largest Neutrino Detector Completed at South Pole Victory for sharks: U.S. bans shark finning Why is the north magnetic pole racing toward Siberia? 11 - Contributions: Applying Lean Principles to Combat Waste The Article on Best Practice in a Fabrication Environment published (2) in issue 88 of PWL for December 2010, outlines knowledge confirmed in practice, that in any industrial welding operation not yet specifically optimized, there is ample opportunity to improve economic results by applying Lean principles. An Article on Applying Lean to Welding Operations was published on the Welding Journal of April 2007 on page 32 and it reports on the practical results obtained in a series of case studies. The fact that Lean is not first priority as it should always be, might be the research object of sociologic studies on internal relationships among the various hierarchical functions in any Company. But it is probably mostly the result of laziness, because disturbing entrenched habits may rouse mighty conflicts which most people want to avoid, even at the cost of heavy losses. That is why, in view of the long term gains to be collected once the entire organization embraces Lean principles, it is probably advisable in most situations to hire external help from consultants experienced in making the first review and preparing a working plan to implement. All would gain from more efficient operations, but it is true that without the constant urging from the owner or the chief executive officer, nothing real will occur. The critical role of top management for introducing Lean activities as applied to welding is known in the case studies examined. Eliminating waste is the focus of the Lean process. It is achieved through a few principles to be adopted by the whole organization. The first goal consists in realizing the ideal of performing top quality work with no defects, first time and then always. Applying Lean would begin with making perfect fillet welds, eliminating overwelding and assuring adequate weld penetration. Minimizing waste is the second, through removal of all no value actions and skilled management of resources. Continuous improvement is the third, by dynamic change through product-process development and information exchange. Flexibility, meaning the capability of rapid change of setup, to deal efficiently also with small lot sizes, is the fourth goal. The last one consists in developing fruitful relationships with suppliers by timely information sharing. Among the most useful research purposes of the examination of a running operation would be a serious design review to improve fit-up and reduce assembly time. Welding wire selection and usage should be scrutinized for unifying sizes and improving logistics. Welder retraining may be advisable. Gas usage should be monitored and standardized. In the case study reported in the above article, significant savings were obtained in the first year. It should be understood that the maximum efficiency of the program could take place only by long time application of all principles, and by constant monitoring and improvement of performance. The author of the article stresses that the keen involvement of the main authority assured the success of the Lean application in more than 100 cases treated by his team. It is interesting to note that the author urges to implement the Welding System Control Measures proposed by the ISO 3834 Part 6, standard mentioned in this publication in section 2 above. Curious readers are urged to seek the WJ article (April 2007, page 32). 12 - Testimonials On Thu Nov 25 13:33:57 2010, the following was received: Name: Paul Daniel Thank you for taking the time to answer my questions, I really appreciate it.
[Note: with reference to the Article The Dangers of Hexavalent Chromium,
published (7) in last issue (PWL#088) the reader who proposed the subject posted the following comment:] Thu Dec 02 01:05:54 2010 13 - Correspondence: a few Comments 13.1 - After the last issue article (11) on Submerged Arc Welding Electrode Extension Nozzles, a kind reader posted a comment summarizing his experience with these devices. See his note at Tipmate Trendsetters. 13.2 - I am always amazed anew, though by now I should know better.
13.3 - Following the case of the query of section 4, when in need of a correct answer, don't ask only for a partial answer (in this case which consumable...) but present the situation with as much detail as feasible, explaining what you would like to do. The expert will then try to find the best options available. 13.4 - Inadvertent readers use sometimes the Welding-talk page for asking questions. It will not help, especially if they fail to write their e-mail. Welding-talk page is reserved for readers' notes relating personal experience with practial welding applications. For asking questions, only the Contact Us page form should be used. 14 - Bulletin Board 14.1 - You can download at no cost a sample Chapter from the book: Optical Microscopy of Fiber-Reinforced Composites 14.2 - LAM, Laser Additive Mfg. Workshop, 3rd Annual 14.3 - ASNT (American Society for Nondestructive Testing) 14.4 - Follow SiteSell to discover new avenues. SiteSell Facebook SiteSell Twitter On SiteSell Twitter, visitors will learn who SiteSell is, through each person delivering personal insights into SiteSell... his news, his interests and perspectives. They can interact with each "SiteSeller" too, asking questions of programmers, coaches or anyone else. SiteSell YouTube SiteSell Blog Case Studies Retirees Jump Start Your New Initiative: Removing the last Barrier to Indecision: The 90 Day Guarantee: See: Order NOW!
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Bulletin 57 - PWL#089B Dispersion Strengthening aluminum alloys, aluminum weldability, literature survey report, mechanical properties PWL#089B - Resources on Dispersion Strengthening Aluminum Alloys, Weldability of DS Aluminum Alloys, Literature Survey Report: Nano-Dispersion Strengthening of Aluminum, Mechanical Properties of Metallic Composites, Advantages of Aluminum P/M Technology, Aluminium Matrix Composites Materials and much more...
Important AnnouncementFor assembling at no cost your own Encyclopedia Online, See a note on Your Opportunity at the beginning of this page, just above the Table of Contents. We urge our readers to Bookmark this page or to subscribe to our Welding Site Blog by clicking on the orange buttons under the NavBar in each Website page.(www.welding-advisers.com)
Introduction This Mid January Bulletin #57 is now integral with and appended to the regular PWL#089 publication. The subject of this Bulletin is a collection of Online Resources on Dispersion Strengthened Aluminum Alloys as additional information completing that presented in section 7 above with authoritative references. Links to the Mid Month Bulletin Pages are listed in the regularly updated page on Welding Resources (Opens a new Window). We urge our readers to Bookmark this page or to subscribe to our Welding Site Blog by clicking on the orange buttons under the NavBar in each Website page.(www.welding-advisers.com) The addresses reported hereafter were live and correct at the time of their publication. There is no guarantee that they will always be so, because they are administered by the sources themselves and are under their control. Note: References to articles or other documents are given here in 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 selected them 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. If the information is important to you as we hope, you may save the selected pages in a suitable folder on your Computer for easy reference. You are welcome to forward this page to those of your friends who may profit of this information. Resources Summary - Dispersion Strengthening alloys (6 pages) Microstructure and Creep Properties of Dispersion-Strengthened Aluminum Alloys (19 pages) Literature Survey Report: Nano-Dispersion Strengthening of Aluminum (10 pages) Nano-Aluminum: Small Size Leads to Big Properties Weldability of DS Aluminum Alloys Advantages of Aluminum P/M Technology Principles and examples of Dispersion Strengthening An Investigation of Alloying Effects in Aluminum Dispersion Aluminium Alloys: Strengthening Dispersion Hardening (10 pages) Dispersion Strengthening (Presentation 12 slides) Precipitation hardening The Science and Engineering of Materials, 4th ed Cast Aluminum Alloy for High Temperature Applications (8 pages) Solid Solution, Precipitation, and Dispersion Strengthening (28 frames) Oxide Dispersion-Strengthened (ODS) Materials (15 frames)
http://osiris.seas.ucla.edu/seminars/ods.pdf
Strengthening Mechanisms of Metals: Part One Strengthening Mechanisms in Metals (61 frames) http://www.mrt.ac.lk/material/strengthening.pdf Aluminium Matrix Composites Materials (28 pages) http://www.eaa.net/eaa/education/TALAT/lectures/1402.pdf Aluminium matrix composites: Challenges and opportunities (16 pages) The Mechanical Properties of In-Situ Composites Metal Matrix Composites – Processing Techniques Based on Powder Metallurgy Read more on Joining-Aluminum-MMC in the following online publication: Strengthening mechanisms in aluminum containing coherent Al3Sc precipitates and incoherent Al2O3 dispersoids (Downloadable paper) For Sale Development of Dispersion-Strengthened aluminum Alloys (Paper for sale) Selection and Weldability of Dispersion-Strengthened Aluminum Alloys Mechanical Properties of Metallic Composites (Book for sale) The Aluminum Metal Matrix Consortium
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