Gas Metal Arc Welding - Lab Report Example

WELDNG LAB REPORT Name: Institution Contents 1.0. Introduction………………………………………………………………………………… 3 2.0. Learning objectives ………………………………………………………………………….3 3.0. Tools and Equipment ………………………………………………………...………..…….3 4.0. Safety and Health ……………………………………………………………………………4 5.0. Theory ………………………………………………………………………………..……...5 6.0. Procedure …………………………………………………………………………...………..7 7.0. Results………………………………………………………………………………..………8 8.0. Problems and possible remedies…………………………………………………..…………9 9.0. Conclusion………………………………………………………………………………….13 10.0. References ……………………………………………………………………………...14 11.0. Safety audit report ……………………………………………………………………...15 1.0. Introduction Gas metal arc welding refers to a welding process in which an electric arc is formed between an electrode wire and a metallic work piece. The wire electrode s usually consumed during the welding process while the metal work piece is heated to melt hence forming the joint. A shielding gas is usually fed through the welding gun is provided to cushion the welding process from impurities within the surrounding air. Alongside the metal piece and the wire electrodes, a voltage source is required to provide a steady current that drives the whole welding process. Gas metal arc welding exists in two sub types: Metal Inert Gas welding (MIG) and Metal Active Gas welding (MAG) 2.0. Learning objectives Upon successfully completing this lab session, every group member was expected to do the following: I. Be able to follow the proper safety and health procedures for both metal inert gas welding and metal active gas welding as well as welding in broad perspective. II. Identify the required equipment and set up all the equipment required to carry out both metal inert gas welding and metal active gas welding III. Create various strong joints such as Butt, Corner, Edge, Lap and Tee Joints using metal inert gas welding and metal active gas welding III.1. Tools and Equipment used In order to successfully carry out the two forms of Gas metal arc welding, the following tools and equipment were used. I. Voltage source II. Leather gloves III. Wire brush IV. Apron V. Pieces of metal VI. Electrode holder VII. Electrodes VIII. Head shield IX. Chipping hammer 4.0. Safety and Health The following list presents a list of health and safety regulations that were adhered to during the welding process in the welding laboratory. I. All personnel within the welding laboratory should wear a face shield and safety glasses at all times within whenever in the lab. II. Always wear an apron and leather gloves while in the lab III. Students should obtain permission from instructor before attempting anything in the lab IV. While in the lab, do not watch the ultraviolet rays that spatter from metal surfaces when welding using eye without a head Shield V. Oxygen and Acetylene gas cylinders should be stored separately VI. All equipment connected to compressed oxygen and acetylene gas cylinders should be securely chained VII. All gas cylinders should be stored outside in as a safe area VIII. Strictly adhere and follow the operating procedures for equipment as provided in the operating manuals of the same equipment IX. Do not expose welding equipment to oil or grease as this may result into spontaneous fires, ensure you always work on a clean bench. X. All welding work should be carried out at a comfortable area; preferably good welding will be done away from the flammable materials. XI. Do not disturb or inconvenience in any manner other students who might still be working. XII. Do not work on any welding exercise without a fire extinguisher by your side. Ensure the fire extinguisher is in a proper working condition. 3.0. Theory During arc welding, the fundamental principle often involves continuous heating so as to melt the base metal by use of an established electric arc. An electric arc forms when there exists a potential difference between the metal coating, usually found at the rear end of the electrode, and the surface of the working base metal. The arc therefore supplies significantly sufficient heat to melt the surface of the base metal and the electrode end which in turn forms a pool of molten metal substance between the two surfaces. Welding joints are thus formed in this manner. T-joints for instance are formed by joining two metallic base plates with one held in a perpendicular position relative to the other, with an angle of 450 between the joint surfaces. This allows equal amount of both heat and metallic filler is distributed onto both surfaces during welding. The following figures show some of the commonly made joints using ether Metal Inert Gas welding (MIG) or Metal Active Gas welding (MAG) in a welding laboratory. Fig 4.1. Welding Joints Parts of a weld Photograph 1: Parts of a weld 4.0. Procedure for Gas metal arc welding Gas metal arc welding is done using the following procedure and sequence of activities Metal Inert Gas Welding. I. Cleaning: - The metal surface is cleaned with aid of a wire brush before the start of the welding process. II. Place the weld as close to the metal surface as possible III. Insert a new electrode to the electrode holder and then strike an arc IV. While reading the voltage reading scale, adjust the electric current to match the electrode size being used. It is usually advisable to maintain an arc length of about 1/16 and 3/32 in diameter between the metal plate and the electrode end point. V. Weld along the base of the metal from the left to the right hand side VI. Maintain the electrode in the electrode holder at an almost perpendicular position with slight tilt all through the welding process. 5.0. Results The following photographs show complete welds as carried out by our group using the earlier on mentioned tools and equipment and procedures. i. Photograph of a corner Joint done by several group members Photograph 2: A completed Corner Joint 6.0. Problems and possible remedies There are a number of problems experienced during the lab session. Some were as a result of mere negligence by the students to adhere to some of the safety and health precautions as expected while in the laboratory. i. Untidy working environment It is always advisable to return all the tools and equipment to their initial secure places. However, as depicted in the photograph bellow, the students failed to adhere to this requirement. They rather opted to leave all the tools and equipment, gas cylinders, gloves, apron and electrode holders, bundled on the bench from where they had been working from. This is risky as it can be a source of accidents within the laboratory Photograph 3: Unsorted Tools and Equipment The above problem can be easily solved through emphasis on the need to stick and operate within the set health and safety measures while in the laboratory. Students should be encouraged to be responsible enough to pay strict adherence to such rules and regulations. ii. Uneven distribution of the molten metal filler As shown in the photograph bellow, there was inconsistent distribution of the melting electrode on the metallic pieces. While some group members had an equal distribution of the molten metal, others kept on trembling with the electrode holder hence the uneven distribution as shown in the photograph bellow. This eventually resulted into a rough weld surface. Photograph 4: Uneven distribution of molten filler This problem can easily be solved through exposure. The students should therefore make arrangements to carry out more lab sessions on welding in order to acclimatize themselves with the activities involved. This will help them produce more consistent welds and of a smooth texture. The overall quality of weld depends on the level of exposure and experience with welding processes. iii. Worn out tools and equipment Some of the tools and equipment availed to the students for use during the lab experiment were in there worst states. The photograph bellow shows a voltage source with worn out electrical cables, often without insulation cover. This could easily expose the students to accidents such as electrocution, not because of negligence but due to the state and condition of the same equipment. Photograph 5: Worn out Voltage Source The most viable solution to worn out tools and equipment is to either replace them with new ones or repair the worn out parts of the same equipment. For instance in the photograph above, the best solution will therefore be replacing the worn out cable with a new one or providing an insulating material for the exposed and naked live wires. iv. Poor storage of tools and equipment According to the conventional lab requirements, gas cylinders should be stored outside the laboratory in a secure and safe place. However, in the laboratory in which the experiment was carried out, gas cylinders were kept inside the laboratory. This is illustrated as shown in the photograph below. In case of gas leakage or mishandling of the gas, t can easily result into an enormous fire especially in such a confined building. Photograph 6: improper storage of Gas cylinders The above elaborated problem can easily be solved by providing an alternative storage place for the gas cylinders outside the lab confinement. The lab management should design a designate storage facility next to the lab for safe storage of the gas cylinders. This is not only for the safety of the students but also the lab management and technical team as well as the institution as a whole which as things are, stand a risk of huge fires due mishandling of gases. 7.0. Conclusion A number of conclusions can be deduced from the lab session as conducted. For instance, at the end of the above described lab session, group members learnt the following: I. The problems that occur during Gas Metal Arc Welding can easily be solved through adherence to lab safety and healthy rules and regulations II. In order to produce the best quality of a gas metal arc weld, the involved student must calculate and maintain the angles required, concentrate on the welding process as well as ensure a steady electrode movement and speed during the welding process. III. The group members also learnt of the various factors that affect the overall quality of the arc weld. Such factors include among others, the thickness of the metal, the type of the electrode used and the potential difference developed during the welding process. References Hollatz, A. F. H. (2001). A system dynamics study for the adaptive control of the gas metal arc welding process. Lund, R. A. (2007). Multivariable computer control of a gas metal arc welding process. Madison, Wis: University of Wisconsin Minnick, W. H. (2008). Gas metal arc welding handbook. Tinley Park, Ill: Goodheart-Willcox Co. Naidu, D. S., Ozcelik, S., & Moore, K. L. (2009). Modeling, sensing and control of gas metal arc welding. Amsterdam: Elsvier. Schmitkons, J. W. (2007). Analysis of adaptive control systems for gas metal arc welding. Madison, Wis: University of Wisconsin. Walsh, S. R. (2010). Studies in computer control of the short circuit Gas Metal Arc welding process. Wang, F. (2009). Simulation of metal transfer and weld pool development in gas metal arc welding of thin sheet metal. Xu, G. (2009). Simulation of drop formation and metal transfer in gas metal arc welding. Safety Audit Report Name(s) and group number the student(s) completing this form: Date of inspection: Area being inspected: Description of hazard and safety issue Suggested solution to hazard Type of control hazard* 1 Worn out and faulty tools and equipment Repair and replacement Personal protection and equipment 2 Improper storage of tools and equipment Design proper storage facilities Personal protection and equipment 3 Untidy working environment Adhere to safety rules and regulations Personal protection and equipment 4 Uneven welding surface More practice and experience required Engineering 5 6 7 8 Read More

This allows equal amount of both heat and metallic filler is distributed onto both surfaces during welding. The following figures show some of the commonly made joints using ether Metal Inert Gas welding (MIG) or Metal Active Gas welding (MAG) in a welding laboratory. Fig 4.1. Welding Joints Parts of a weld Photograph 1: Parts of a weld 4.0. Procedure for Gas metal arc welding Gas metal arc welding is done using the following procedure and sequence of activities Metal Inert Gas Welding. I. Cleaning: - The metal surface is cleaned with aid of a wire brush before the start of the welding process. II. Place the weld as close to the metal surface as possible III.

Insert a new electrode to the electrode holder and then strike an arc IV. While reading the voltage reading scale, adjust the electric current to match the electrode size being used. It is usually advisable to maintain an arc length of about 1/16 and 3/32 in diameter between the metal plate and the electrode end point. V. Weld along the base of the metal from the left to the right hand side VI. Maintain the electrode in the electrode holder at an almost perpendicular position with slight tilt all through the welding process. 5.0.

Results The following photographs show complete welds as carried out by our group using the earlier on mentioned tools and equipment and procedures. i. Photograph of a corner Joint done by several group members Photograph 2: A completed Corner Joint 6.0. Problems and possible remedies There are a number of problems experienced during the lab session. Some were as a result of mere negligence by the students to adhere to some of the safety and health precautions as expected while in the laboratory. i. Untidy working environment It is always advisable to return all the tools and equipment to their initial secure places.

However, as depicted in the photograph bellow, the students failed to adhere to this requirement. They rather opted to leave all the tools and equipment, gas cylinders, gloves, apron and electrode holders, bundled on the bench from where they had been working from. This is risky as it can be a source of accidents within the laboratory Photograph 3: Unsorted Tools and Equipment The above problem can be easily solved through emphasis on the need to stick and operate within the set health and safety measures while in the laboratory.

Students should be encouraged to be responsible enough to pay strict adherence to such rules and regulations. ii. Uneven distribution of the molten metal filler As shown in the photograph bellow, there was inconsistent distribution of the melting electrode on the metallic pieces. While some group members had an equal distribution of the molten metal, others kept on trembling with the electrode holder hence the uneven distribution as shown in the photograph bellow. This eventually resulted into a rough weld surface.

Photograph 4: Uneven distribution of molten filler This problem can easily be solved through exposure. The students should therefore make arrangements to carry out more lab sessions on welding in order to acclimatize themselves with the activities involved. This will help them produce more consistent welds and of a smooth texture. The overall quality of weld depends on the level of exposure and experience with welding processes. iii. Worn out tools and equipment Some of the tools and equipment availed to the students for use during the lab experiment were in there worst states.

The photograph bellow shows a voltage source with worn out electrical cables, often without insulation cover. This could easily expose the students to accidents such as electrocution, not because of negligence but due to the state and condition of the same equipment. Photograph 5: Worn out Voltage Source The most viable solution to worn out tools and equipment is to either replace them with new ones or repair the worn out parts of the same equipment. For instance in the photograph above, the best solution will therefore be replacing the worn out cable with a new one or providing an insulating material for the exposed and naked live wires. iv.

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