|
Welding-steeland steel weldability:SOLUTIONS with Effective, Powerful Advice
What is in here for me? Welding-steel and iron base alloys are presented in this page. A brief account on versatility of iron and steel follows hereafter. The importance of versatility: Common steel is quite economical and available in many shapes and dimensions. Besides that, the single reason that makes steel so important and commonplace for many applications is its versatility. It is the capability of presenting economically a very wide range of mechanical and other properties. This ability is based on the fact that a tailored chemical composition makes the material responsive in subtle ways to the application of precise heat treatments. If you did not yet find what you need, why not typing your question in the following Search Box?
As a result of proper heat treatment, the steels develop definite micro structures that display those all important mechanical properties. The sought for properties give to steel structures their unique quality and implement their unequaled usefulness. Welding-steel enlarges and amplifies even more this versatility.
Welding-steel is not always easy or even possible. Steels are generally classified according to their main application (construction steel [weldable], tool steel, bearing steel [not weldable]...). They may be classified also by other characteristics that make them suitable for special processing (free machining steel [not weldable], case hardening steel...) or to some other important quality that definitely separates them as a special class (stainless steels). Most common steels are weldable, but there are many types where special Welding-steel procedures must be implemented to perform acceptable welds. Occasionally one can meet a definite steel type which can only be joined by sophisticated processes like solid state (that is without melting), which are not available to the common welding job shop. It may be important though to acknowledge the limitations. Are there problems in Welding-steels? Full knowledge of the material and its condition will determine if and which problems are likely to crop up in welding. This knowledge may affect Process and parameters. Hardened and tempered low alloy steels are likely to lose their mechanical properties (strength and hardness) during welding. But not only that: they may be re-hardened by quick cooling in the volume that was heated by welding in the zone near the weld, called Heat Affected Zone (HAZ), and crack. Such steels are identified as having limited weldability. This is why one should have before welding, full information on material and condition of the job at hand. What benefits can be found here? Essentially a short overview of problems concerning Welding-steels. However as types and conditions of various steels can be very different, so could be the problems and the answers. In order to get solutions one should focus on a general or specific problem. Ask your question by e-mail. Click on the Contact Us button in the NavBar. Welding-steel is concerned with the weldability of the various kinds of this material. Low carbon steels, those having less than 0.25% carbon, display good weldability, meaning that they can be generally welded without special precautions using most of the processes available. This is true, however, only if the content of sulfur and of phosphorus is very low (less than 0.04 %). As these steels cannot develop exceptional mechanical properties neither by heat treatment nor by thermo-mechanical means, there is no way to damage their basic properties by heating to melt or to weld them. Low alloy steel should be considered separately. They are called this way because, besides iron, carbon, silicon and manganese, they include also other alloy elements (Cr, Mo, Ni etc.) but usually in cumulative proportion under 5%. The carbon content is most important: up to about 0.25% C no special problems in Welding-steel should be found. The best practice would call for welding in the annealed condition, and then to provide for heat treatment if required and possible. Filler metal should be selected with care, because dilution with the base metal may alter the final properties of the joint. In certain cases (heavy sections) preheating may be recommended. Stress relieving after welding is also common practice. What does the process... FRICTION WELDING, as a solid state process with lower than melting temperature (that is: not a fusion welding process), presents no problem for Welding-steel in most cases, even for different materials combinations, which may not be welded jointly by any other process. Carbon and low alloy steels can be joined under wide ranges of Welding-steel conditions. Medium carbon and alloy steels can be friction welded but with more strictly controlled parameters, because of their hardening properties, and then only for non stressed members. Welding-steel is not applicable for free machining steels by any process, including friction welding, except when mechanical properties and especially fatigue strength are not important at all. The reason is that free machining steels contain in their composition sulfur, lead or selenium, for breaking the machining chips: the same elements interfere with welding producing solidification (hot) cracks. Heat treated steels tend to lose less of their properties with friction welding even if heat is localized and limited to a narrow zone. See Friction Welding Processes, and also
Regular practice... RESISTANCE WELDING, either spot or seam is widely used for Welding-steel.
ANSI/AWS C1.1M/C1.1:2000 (R2012)
ANSI/AWS C1.4M/C1.4:2009 The surface condition of the materials is critical for the production of consistent spot or seam welds as it influences surface resistance which in turn, in Resistance welding, determines the heat developed by electric current flow. Tip!: Steel sheets for resistance welding should always be clean and free from oil, paint and rust. Furthermore low quality surface condition can be reflected in material pick up at the electrodes, which rapidly contributes to produce low quality welds. Tip!: Electrode surfaces must be dressed and reconditioned at regular intervals to keep them clean and in correct shape. Resistance Welding-steel of low carbon steels can be performed even when these are coated by a thin layer of a corrosion resistance metal (zinc, aluminum, nickel, tin). However nonmetallic coatings must usually be locally removed before resistance welding. Electrode composition for Resistance Welding has been established by RWMA (Resistance Welder Manufacturers' Association). The classification includes copper alloys in Group A, divided in Class 1, 2 and 3, and refractory metals in Group B, divided in classes 10 to 14. The mechanical and electrical characteristics of each type make each of them best suited to welding a particular material.
International Standard ISO 5182: Materials for Resistance Welding Electrodes can be found at ISO. Schedule adaptation of parameters such as preheat, forge pressure and postheat, together with precise timing and sequence of the various phases permits a large measure of control upon the metallurgical characteristics of weld nugget. When correctly employed, permit to overcome the difficulties sometimes associated with Welding-steel of medium carbon or with low alloy steels. Tip!: Equipment manufacturers may insist that their specialties are equipment and instrumentation, and they are not material experts. Yet they are able and willing to help, they may have a development laboratory, and they will do their best to solve a manufacturing Welding-steel problem by suggesting a proper schedule. It may be worth trying to have them involved. Independent laboratories like EWI will take a project for a fee, research and solve it. Mostly for thin stuff... Welding-steel by manual GAS WELDING or more properly by oxyacetylene process, mostly of thin gauges, especially low carbon or mild steel in the form of thin sheets or tubes, is performed regularly with success. The characteristics of the flame can be controlled to be neutral, carburizing or reducing, as better adapted to the work on hand, but in any case the flame and its surrounding atmosphere can effectively protect the workpiece and the tip of filler metal, if used, from contamination from air.
ANSI/AWS A5.2/A5.2M:2007
See Oxyacetylene Welding Tips. Most popular... ARC WELDING is widely used for welding steels. The most popular manual process for Welding-steel is probably Shielded Metal Arc Welding (SMAW). Electrode Classification is established by the American Welding Society.
See Shielded Metal Arc Welding Tips. An Article on the AWS Classification of Welding Electrodes was included in our Practical Welding Letter No. 01 of September 2003. An Article on Heat Treatment of Carbon Steels was included in our Practical Welding Letter No. 06 of February 2004. To read the article click on PWL#006. An Article on Selection of GMA and FCA Filler Welding Electrodes was included in our Practical Welding Letter No. 06 of February 2004. To read the article click PWL#006. A section including information on Comparison of Filler Metals was published in the May 2004, Issue No. 09 of Practical Welding Letter. An Article on Pipe Welding is included (2) in our Practical Welding Letter No. 11 of July 2004. An Article on Filler Metals in the form of Flux Cored Wires was published (4) in the Feb. 2005 Issue No. 18 of Practical Welding Letter. To see the article click on PWL#018. An Article on Basic facts on Steel was published on the May 2005, Issue No. 21 of Practical Welding Letter. To read the article click on PWL#021. An Article on Weldability Testing for Weld Repair was published in the November 2005 Issue No. 27 of Practical Welding Letter. Click on PWL#027 An Article on Filler Metal for controlling Hydrogen Induced Cracking was published in section (4) of Issue 44 of Practical Welding Letter for April 2007. Click on PWL#044 to read it. A short note on Welding together Different Carbon Steels (3) was published in issue 45 of Practical Welding Letter for May 2007. For reading the article click on PWL#045. An Article on TRIP Steels was published (11) in Issue 50 of Practical Welding Letter for October 2007. An Article on Parameters for welding 1/2" steel plates was published (3) in Issue 51 of Practical Welding Letter for November 2007. An Article on Filler Metals with Exothermal Additions was published (4) in Issue 51 of Practical Welding Letter for November 2007. A note on Stress Relieving was published (8) in Issue 88 of Practical Welding Letter for November 2010. An Article on Buttering on High Carbon-Equivalent Steel was published (3) in Issue 134 of Practical Welding Letter for October 2014. An Article on Filler Metal Spec Changes was published (4) in Issue 144 of Practical Welding Letter for August 2015. Two new Website Pages on Weld-preparation and on Online Resources Links, were introduced (8) in Issue 147 of Practical Welding Letter for November 2015. An Article on Choosing a Steel Filler Metal appropriate for the Base Metal was published (4) in Issue 149 of Practical Welding Letter for January 2016. An Article on Changes in D1.1:2015, Structural Welding Code — Steel was published (2) in Issue 150 of Practical Welding Letter for February 2016. An Article on An Update on AWS Classification Requirements was published (4) in Issue 154 of Practical Welding Letter for June 2016. An Article on Induction Coupled Thermomagnetic Processing was published (2) in Issue 155 of Practical Welding Letter for July 2016. An Article on Nanostructured Metal was published (7) in Issue 162 of Practical Welding Letter for February 2017. See also our page on Stress Relieving. To receive regularly by e-mail at no cost the periodic publication above, please click and subscribe. Other useful information can be found by clicking on the FAQ Button in the Top Left Side NavBar. For Gas shielded processes (GTAW or TIG and GMAW or MIG) the specifications are:
See also ANSI/AWS A5.01M/A5.01:2008
AWS issues a Filler Metal Comparison Chart listing commercial products.
See Tig Welding Tips, and also Selection of Electrode type depends on many factors: there is no all-purpose electrode for every welding situation. The "best" electrode is the one that permits an acceptable weld to be performed at minimum cost (all included). Tip!: it may be advisable to follow recommendations as published by established suppliers. However, Electrodes from different suppliers, nominally satisfying the requirements of a given Specification, may perform quite differently in any given situation. Therefore a few tests on Welding-steel should always be conducted before selecting a definite product for a repetitive job, in order to find the best solution for the given application under the prevailing circumstances, including welder's skill.
See Flux Cored Arc Welding Tips. To receive all the issues of PWL as they are published, please subscribe. Higher productivity... SUBMERGED ARC WELDING (See a description of this process in
Groove geometry and size have a definite importance in determining the success of the operation and its overall cost. It may also influence the size of the wire used, the flux and the maximum speed of welding. For low carbon Welding-steel FLUX-CORED ARC WELDING is an accepted process. Filler metal are classified in:
See Submerged Arc Welding Tips. A new page was recently added to this website. It is found by clicking on Steel Finishing.
If you did not yet find what you need, why not typing your question in the following Search Box?
NEW RESOURCES
Looking for more Online Reference Links?
Any questions or comments or feedback? Write them down and send them to us by e-mail.
You are entitled, as you probably know by now, to a FREE Subscription to our Practical Welding Letter and to a FREE download, right to your computer, of our book in pdf format on PRACTICAL HARDNESS TESTING MADE SIMPLE. It could help you for your hard welding problems.
To reach a Guide to the collection of the most important Articles from Past Issues of Practical Welding Letter,
Back Home
Material Identification.
How I Quit My Job No Commute = Less Stress
POWERED BY:
Click on this Logo NOW! Watch - The Video: and also
Copyright (c) 2003-2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017  Welding-steel may be simple or complex: it depends on weldability, which studies how steel reacts to heat, in and near the weld. See it here...
|
