The filler metal for gas tungsten arc welding is a hand fed consumable welding rod. K to 12 smaw welding learning module by tactical foundati. The flux coatings burn in the intense heat and form a blanket of smoke and gas that shields the weld puddle from the air. With root pass welding, quickly move the arc from the weld pool to the plate edge.
Users should also consider the selection of the welding process, welding procedure, or consumable. Consequently, codes and standards developed by the american welding society specify exactly how a joint must look when the job is completed. However, thermite and flash butt are used for joining continuous welded rail. Do not weld where flying sparks can strike flammable material. A welding defect is any flaw that compromises the usefulness of a weldment. Slag is a vitreous material that occurs as a byproduct of stick welding. Ensure ppe is properly stored and maintained when not in use. Pdf technological development accompanied the need to get a.
Joint included angle too small electrode or torch angle is incorrect. Safety standards are mandatory rules set and enforced to eliminate or reduce, a. The purpose of the welding handbook for maritime welders is to provide guidance in modern welding and related processes and to provide the welder with a source of practical information on the right solution to specific onboard welding problems. A basic understanding of electrical terms is necessary to fully understand shielded metal arc welding. It gives less spatter than most other rutile electrodes, the slag is easy to remove and the weld bead is smooth and even. This document is not an application manual and does not contain a complete statement of all factors pertaining to those topics. Cracks must be ground out with a file or grinder, and. Weld steel pipe in 6g using smaw by lawrence lerias 904. Experience gained from user contact and welding training of crewmembers showed that. Guidelines for shielded metal arc welding smaw warning this document contains general information about the topics discussed herein. Protect yourself and others from flying sparks and hot metal. Industrial technology maintenance maintenance welding.
Welding defects may occur either outside or inside the weld metal. Welding defects can be defined as the irregularities formed in the given weld metal due to wrong welding process or incorrect welding patterns, etc. Stick welding application shielded metal arc welding is one of the most widely used processes, particularly for short welds in production, maintenance and repair work, and for field construction. The most popular processes are shielded metal arc welding smaw, gas metal arc welding gmaw and gas tungsten arc welding gtaw.
Nonconsumable electrodes are only used as a conductor for the electrical current, such as in gas tungsten arc welding. Molten metal travels from the electrode via the electrical arc and is deposited into the work piece. Weld defects in austenitic stainless steel sheetseffect of. As an example, any change to the following essential variables for performance qualification with shielded metalarc welding smaw will require requalification. Corrosionpedia what is shielded metal arc welding smaw. Smaw metal filler eival kclta tn olapkela rnc anoteaeital ano ou0 uepn nupnva uetaaalk. Shielded metal arc welding, which is also known as stick welding, is the most widely used process. Welding circuit for shielded metal arc welding smaw. The shielded metal arc welding smaw stick process generates an arc between a fluxcoated consumable electrode and the workpiece. Be alert that welding sparks and hot materials from welding can easily go through small cracks and openings to adjacent areas. Pdf classification of welding defects using gray level histogram. Shielded metal arc welding smaw, also known as manual metal arc welding mma or mmaw, flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld.
The welding shall be done using the shielded metal arc welding smaw. All of these methods employ an electric power supply to create an arc which melts the base metals to form a molten pool. Shielded metal arc welding smaw, also known as manual metal arc welding mma or mmaw, flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld an electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc. Smaw is well known for its versatility because it can be used in all welding positions, and in both production and repair welding situations. Welding imperfections are classified according to iso 6520 while their acceptable limits are specified in iso 5817 and iso 10042. It is easy to strike and restrike and therefore also good for tack welding. Om2237 page 1 section 1 safety precautions read before using. Stick welding shielded metal arc welding or smaw although mostly considered archaic nowadays, especially when compared to the tig and mig, shielded metal arc welding, or stick welding, is a manual welding technique that relies on a consumable electrode coated in flux that is then used to lay the weld.
Weld carbon steel plates using smaw welding carbon steel plates using smaw mee726 2. There are different types of cracks, depending on the temperature at which they occur. Saw mma basic electrodes mig mag solid wire 5 10 15 20 25 30. Welding and related processes for repair and maintenance onboard 14th edition 2nd revision.
Welding defects and implications on welded assemblies. Mmawelding manual metal arc, smaw tigwelding tungsten intert gas, gtaw plasma welding submerged arc welding laser welding welding methods other than those mentioned above may also be used. An electrode is a bare metal rod which is usually coated with chemical compounds called flux. Choose the best answer and write the letter only on your answer sheet. Weld defects in austenitic stainless steel sheetseffect. Resistance spot welding is used frequently as a successful joining method for a variety of work commonly in automotive and other manufacturing. What can be done to manage the hazards associated with smaw. So below well learn about the 7 most common welding defects, their types, causes. Students will demonstrate competency in shielded metal arc welding.
Use lowhydrogen welding consumables from moisture protective packagings or rebake welding consumables. The crack begins at a void in the welding crater, caused by the solidi. Guidelines for shielded metal arc welding smaw miller welding. Welding on closed containers, such as tanks, drums, or pipes, can cause them to blow up. Depending on the application, other groups may have a say.
Weld defects and how to avoid them welding jobs, equipment. Depending on the type shielding gas, this process is of also known as co. The equipment is relatively simple, inexpensive, and portable. All welding is carried out on the welder s own risk and account. Smaw, gmaw, fcaw, pipeline construction, welding processes, mechanized welding. The flying sparks, hot workpiece, and hot equipment can cause fires and burns. Smaw welding electrodes inconel welding electrode 112 enicrmo3 a basic coated electrode with fully alloyed core wire and reduced coating thickness offers. Welding should be executed by a qualified and experienced welder and adequate safety measures should always be adhered to.
Fume extraction is only one component in reducing welding fume. Set up for welding, brazing, or soldering pipetubing joints shielded metal arc welding set up for welding in the flat, horizontal, vertical, and overhead positions assemble and disassemble smaw equipment adjust parameters and weld ferrous materials with the smaw process gas metal arc welding and flux cored arc welding. Arc welding, shielded metal arc welding, shielding in smaw, electrode coating, welding current, electrode size 11. The defect may differ from the desired weld bead shape, size, and intended quality. In this article, we have covered the welding defects and we see the. The most common track welding functions are electric arc, thermite, and flash butt. The need to chip away slag and replace spent electrodes make this welding process one. The most serious type of welding defect is a weld crack and its not accepted almost. Source extraction local exhaust is a mechanical device used to capture welding fume at or near the arc and filter contaminants out of the air. Understand and apply math skills as they relate to welding module 3. History of welding the art of welding is an ancient one but the science of shielded metal arc welding is relatively new. Welding theory and applications welding and cutting tech industrial maintenance trades wlv 1116 shielded metal arc welding i effective 2006 imm 1734 maintenance welding and metals assessment students will be assessed using the welding mscpas2 test. Defects of different kinds can be cre ated during the welding of austenitic stainless steels, e. Stick smaw welding om2237 206 035a march 2002 arc welding power source cst 250 tig gtaw welding.
Electrode size is nominated by diameter of core wire and is. Welding defects neural network computer vision xray image histogram. Weld defects and how to avoid them welders universe. Standard arc welding processes such as smaw, gmaw, and fcaw are used to weld manganese and carbon steel track components. Jun 16, 20 k to 12 smaw welding learning module by tactical foundati.
Introduction welding is the process of coalescing more than one material part at their surface of contact by the suitable application of pressure or heat or both at the same time. Smaw, gmaw 5 too much welding amperage, arc length, or arc voltage preventive measures. Oct 31, 2018 shielded metal arc welding smaw is a fusion welding process that uses a consumable, fluxcoated electrode to create an arc between the electrode and the work piece. The symbols shown below are used throughout this manual. The pipeline construction industry uses the welding processes extensively before laying it down under surface. Because the electrodes used in the shielded metal arc welding process are consumable, it is necessary for the person performing the welding to periodically replace the electrode. Check welding equipment and personal protective equipment ppe for defects and damage before beginning work. Many times a combination of fume extraction, training, process change, andor consumable change is needed to reduce the amount of fume to acceptable levels.
Mee726 weld carbon steel pipes using smaw welding carbon steel pipes. The flash butt method is used in the plant to create quartermile. Industrial technology maintenance maintenance welding level i. The welding course of study provides students with an opportunity to learn about the industry as it relates to welding. Welding table workpiece connection clamp workpiece lead cable electrode holder electrode lead cable plug to power source input power lead cable arc welding power source nkek.
Shielded metal arc welding is one of the most widely used processes, particularly for short welds in production, maintenance and repair work, and for field construction. Be alert that welding sparks and hot materials from. What are the principle hazards associated with smaw. Shielded metal arc welding smaw is a fusion welding process that uses a consumable, fluxcoated electrode to create an arc between the electrode and the work piece.
However, of the methods mentioned, magwelding is the most commonly used welding method in the industry today. A generalised electrical circuit for smaw is shown in fig. Stick smaw welding 155 095 a july 2005 visit our website at. Ppt smaw welding powerpoint presentation free to download. The most serious type of welding defect is a weld crack and its not accepted almost by all standards in the industry. Accidental contact of electrode to metal objects can cause sparks, explosion, overheating, or fire. Watch for fire, and keep a fire extinguisher nearby. According to the american society of mechanical engineers asme, causes of welding defects can. The filler metal, and the means of protecting it and the. Prepared for major welding processes fcaw, smaw stick, gmaw mig, saw. Electrode size is nominated by diameter of core wire and is determined by the amperage. Lichtenberg electric fusion 1801 sir humpherydavy arc two poles 1860 wilde electric welding 1907 oscar kjellbrogfluxcoated 1909 stroh menger heavy coated 1912 us patent mechanicalproperties 1918 ao smithusa celluosic coating. In spite of the use of welding shield an operator may develop eye pain if he welds continuously for long shifts say 6 to 10 hours. Shield metal arc welding is an arc welding process that uses a consumable electrode to initiate the arc and provide the filler material.
Set up and adjust smaw for welding operations use proper grounding techniques perform tack weld. Students will master a variety of welding competencies including oxyfuel cutting and welding including shielded metal arc welding. If this is not possible, tightly cover them with approved covers. Introduction pipeline is used to transfer gases or fluids from one place to another place by connecting pieces of lengths of pipes together. K to 12 welding learning module linkedin slideshare. In the third installment of the weld defects series we demonstrate three more welding discontinuities. Position welding curtains as needed to protect others in the area from splatter, flash and glare. Applying shielded metal arc welding smaw techniques. Remove slag from and visually inspect welds for defects.
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