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Welding-steeland steel weldability:SOLUTIONS with Effective, Powerful AdviceWelding-steel, welding low carbon steel, welding low alloy steel, iron base alloy welding, weldability, composition, preheating, welding precautions, stress relieving, welding techniques, heat treatments, mechanical properties, welding information, welding links, welding tips, improving welding results, joining questions needing answers: these are some of the items developed in this Site for the benefit of interested readers. What is in here for me? Welding-steel and iron base alloys are presented in this page. A brief account on the importance and versatility of iron and steel in developing their most wanted properties can be found hereafter.
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The single reason that makes steel so important is its versatility or the capability of presenting economically a very wide range of mechanical 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.
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 here. 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.
To receive all the issues of PWL as they are published, please subscribe. The steels can then 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 unequalled 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]...) or to other qualification that make them suitable for special processing (free machining steel [not weldable], case hardening steel...) or to some other important characteristic that definitely separates 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? It depends upon the material and its condition. Also on the Process and its 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 rehardened by heat near the weld, and crack. Such steels are identified as having limited weldability. This is why one should know before welding what are 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. 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 as required. Filler metal should be selected with care, because dilution with the base metal may alter the final properties of the joint. In most cases preheating is recommended and also stress relieving after welding. What does the process... FRICTION WELDING, as a solid state process with lower than melting temperature, 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 or selenium, for breaking the machining chips: the same elements interfere with welding producing cracks. Heat treated steels tend to lose less of their properties with friction welding as the heat is localized and limited to a narrow zone.
Regular practice... RESISTANCE WELDING, either spot or seam is widely used for Welding-steel. For Specification requirements of Resistance Welds see
AWS C1.1M/C1.1-2000 ANSI/AWS C1.4M/C1.4-1999
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, and when correctly employed, permit to overcome the difficulties sometimes associated with Welding-steel of medium carbon or with low alloy steels. Tip!: Although 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 gages, 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.
AWS A5.2-92(R1997)
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.
An Article on the AWS Classification of Welding Electrodes was included in our Practical Welding Letter No. 01 of September 2003. To see the article click onPWL#001 A section including information on Comparison of Filler Metals was published in the May 2004, Issue No. 09 of Practical Welding Letter. Click on PWL#009 to read it. An Article on Pipe Welding is included in our Practical Welding Letter No. 11 of July 2004. To read the article click on PWL#011. An Article on Filler Metals in the form of Flux Cored Wires was published in the Feb. 2005 Issue No. 18 of Practical Welding Letter. To see the article click on PWL#018. An Article on Filler Metals with Exothermal Additions was published in Issue 51 of Practical Welding Letter for November 2007. Click on PWL#051 to read it. An Article on Parameters for welding 1/2" steel plates was published in Issue 51 of Practical Welding Letter for November 2007. To suscribe and receive regularly by e-mail at no cost the periodic publication above, click here. Other useful information you can find 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 A5.01-93(R1999) AWS issues a Filler Metal Comparison Chart listing commercial products. 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. 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. 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 here. To receive all the issues of PWL as they are published, subscribe here. 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:
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