CSWIP: Welding Inspector Exam Quiz!

The main reason for reporting this issue and filing a non-conformance report is that the weld metals composition would be incorrect. TIG welding requires the use of a specific filler wire that matches the composition of the base metal being welded. Using an MMA electrode stripped of flux as filler wire would result in a different composition, leading to an incorrect weld metal composition. This can affect the strength, integrity, and performance of the weld, making it necessary to report and address the issue.

The ratio between the leg length and design throat thickness on a mitre fillet weld with equal leg lengths is 1.414 to 1. This means that the leg length is 1.414 times greater than the design throat thickness.

Carbon is the element with the greatest effect on hardness in steel. This is because carbon can form strong chemical bonds with iron atoms, creating a solid solution called iron carbide or cementite. The presence of carbon in steel increases its hardness by forming a lattice structure that prevents the movement of dislocations, making it more resistant to deformation. Additionally, higher carbon content can also lead to the formation of other hard phases, such as martensite, which further contributes to the overall hardness of the steel.

The elongation percentage can be calculated by subtracting the original gauge length from the final gauge length, dividing it by the original gauge length, and then multiplying by 100. In this case, the original gauge length is 50mm and the final gauge length is 72mm. So, the elongation percentage would be ((72-50)/50) * 100 = 44%.

The most important stage for close scrutiny would be fit-up and root pass welding. Fit-up ensures that the parts being welded together are properly aligned and positioned, which is crucial for the overall strength and integrity of the weld. Root pass welding is the initial weld that penetrates the base metal, and it is essential to ensure proper fusion and penetration to prevent defects such as lack of fusion or incomplete penetration. By closely inspecting fit-up and root pass welding, the welding inspector can identify and address any issues early on, ensuring the quality and integrity of the weld.

Grinding the capping passes flush helps to increase the fatigue life of the component. This is because any irregularities or roughness on the surface can act as stress concentrators, leading to the initiation and propagation of fatigue cracks. By grinding the capping passes flush, the surface becomes smoother and eliminates these stress concentrators, thereby improving the fatigue life of the component.

A typical heat input reading with the MIG/MAG welding process is 1.2KJ/mm. This measurement indicates the amount of energy transferred into the weld per unit length.

The down-slope control in tungsten arc welding is used to help prevent the formation of crater pipe and possible cracking. Crater pipe refers to a depression or groove that can form at the end of a weld, and it can lead to cracking if not properly managed. By controlling the down-slope, the welding process can be gradually slowed down, allowing the crater to be filled and preventing the formation of a pipe. This helps to ensure a smooth and strong weld without the risk of cracking.

AC (alternating current) is the correct answer for the welding of aluminium with the TIG welding process. TIG welding requires a high-frequency alternating current to generate the heat needed for the welding process. AC current allows for better control of the heat input and helps prevent overheating or distortion of the aluminium material. DC-ve and DC+ve currents are not typically used for TIG welding aluminium as they do not provide the necessary heat control and can result in poor weld quality.

The inclusion of an inductance in the welding circuit when using the MIG/MAG welding process is to control the rate of spatter in the dip transfer mode. Spatter refers to the small droplets of molten metal that can be produced during the welding process. By controlling the rate of spatter, the welder can achieve a cleaner and more precise weld. The inductance helps to regulate the current flow and reduces the likelihood of excessive spatter, resulting in a better quality weld.

TIG (Tungsten Inert Gas) welding process would produce the lowest levels of hydrogen in the completed weld under controlled conditions. TIG welding uses a non-consumable tungsten electrode to create the arc and a shielding gas, usually argon, to protect the weld area from atmospheric contamination. This process provides excellent control over the welding parameters, resulting in a high-quality weld with minimal hydrogen content. MMA (Manual Metal Arc), SAW (Submerged Arc Welding), and FCAW (Flux-Cored Arc Welding) processes may introduce higher levels of hydrogen due to the presence of flux or consumable electrodes.

DC+ve refers to direct current with positive polarity. In the MMA welding process, the electrode is connected to the positive terminal of the power source. This configuration allows for deeper penetration because the positively charged electrode attracts negatively charged electrons from the workpiece, creating a concentrated heat source. This concentrated heat results in a deeper weld penetration, making DC+ve the correct answer for achieving the deepest penetration in typical conditions using the MMA welding process.

Weld centerline longitudinal cracks in welded butt joints may have resulted from solidification problems. When the weld metal solidifies too quickly or unevenly, it can lead to the formation of cracks along the centerline. This can occur due to factors such as high cooling rates, improper weld parameters, or inadequate preheating. Hydrogen entrapment can also contribute to crack formation, but in this case, the cracks are specifically attributed to solidification issues. Poor welder skill may result in various welding defects, but it is not directly related to the formation of centerline longitudinal cracks.

The main usage of the arc air process is the removal of defective welds. This process involves using an electric arc to heat and melt the metal, while a high-velocity jet of compressed air blows away the molten metal. This allows for the removal of welds that are deemed defective or need to be repaired. The arc air process is particularly useful in situations where traditional methods of weld removal, such as grinding or cutting, are not feasible or efficient.

The given welding process parameters are measured in KJ/mm, which stands for kilojoules per millimeter. The answer, 0.7 KJ/mm, indicates that the arc energy for the welding process is 0.7 kilojoules per millimeter.

Spray transfer is the best suited metal transfer mode for welding thick plates over 25mm in the flat welding position. Spray transfer is characterized by a high current and voltage, which results in a stable and controlled arc. This mode produces a fine, steady stream of small droplets that transfer across the arc to the weld pool. The high energy and velocity of these droplets allow for deep penetration and efficient fusion of the thick plates. Additionally, the spray transfer mode provides good control over the weld pool and minimizes spatter, resulting in high-quality welds.

Preheating the material to be cut reduces local hardening when considering thermal cutting. This is because preheating raises the temperature of the material, making it more ductile and less prone to hardening during the cutting process. By increasing the material's temperature, it becomes easier to cut and reduces the risk of hardening, resulting in a smoother and more efficient cutting process. Increasing the cutting speed and using propane as a fuel gas may have their own benefits but they do not directly address the issue of local hardening.

The fillet weld's profile is concave because the throat thickness (which represents the minimum amount of weld material) is measured at 8.5mm, which is less than the even length of the weld (15mm). In a concave profile, the weld material is not evenly distributed, resulting in a depression or concavity in the weld.

Arc length is the most difficult welding parameter to control during manual arc welding. The arc length refers to the distance between the electrode and the workpiece. It directly affects the stability and quality of the weld. If the arc length is too short, it can cause the electrode to stick to the workpiece, resulting in an unstable arc and poor weld quality. On the other hand, if the arc length is too long, it can lead to excessive heat input and potential defects such as porosity or lack of fusion. Therefore, maintaining a consistent and optimal arc length is crucial for achieving a successful weld.

The EN/ISO weld symbol differs from the BS weld symbol in that it has the welds elementary symbol placed on a dashed line above or below the solid reference line to indicate a weld on the other side. This means that when using the EN/ISO welding symbol, the placement of the elementary symbol provides information about the location of the weld on the other side of the joint. In contrast, the BS weld symbol does not have this specific feature.

Having a heat input that is too low during welding can lead to high hardness, lack of fusion, and entrapped hydrogen. High hardness occurs because the low heat input does not allow for proper heat treatment of the weld metal, resulting in a harder and more brittle weld. Lack of fusion refers to the incomplete bonding between the base metal and the weld metal, leading to weak joints. Finally, entrapped hydrogen occurs when the low heat input does not provide enough energy to release the hydrogen gas that is produced during the welding process, resulting in hydrogen being trapped within the weld and causing potential cracking and porosity.

Duplex stainless steel is a type of stainless steel that contains both ferritic and austenitic microstructures. It combines the strength and corrosion resistance of both ferritic and austenitic stainless steels, making it suitable for applications where high strength and excellent corrosion resistance are required. Therefore, it can be referred to as ferritic/austenitic stainless steel. Martensitic stainless steel refers to a different type of stainless steel that has a martensitic microstructure, and 316L stainless steel is a specific grade of austenitic stainless steel.

The best way to identify hydrogen controlled electrodes for the MMA welding process is by looking at the electrodes classification code stamped onto the electrode. This code provides specific information about the type and characteristics of the electrode, including whether it is hydrogen controlled. The colour of the flux covering, the electrodes classification code on the box, and the electrode trade/manufacturers name may also provide some information, but the classification code stamped onto the electrode itself is the most reliable and accurate method of identification.

Increasing the heat input can reduce the toughness and yield strength of steel. This is because when the heat input is increased, it can cause the formation of larger grains in the steel microstructure. Larger grains result in decreased strength and toughness, as they provide less resistance to deformation and fracture. Therefore, increasing the heat input can lead to a reduction in the mechanical properties of steel.

A ductile fracture surface typically appears rough and randomly torn, with a noticeable reduction in the area of the fractured material. This is because ductile materials have the ability to deform and stretch before breaking, resulting in a jagged and torn appearance. Additionally, the reduction in area indicates the extent of plastic deformation that occurred before the fracture.

Pre-heating prior to the welding of a carbon steel butt weld is not always necessary. The need for pre-heating depends on factors such as the thickness of the material, the welding process being used, and the specific requirements of the welding code or standard being followed. Pre-heating may be required to prevent cracking or improve the weld quality, but it is not always carried out and can be omitted if post-weld heat treatment is planned. Therefore, the correct answer is "None of the above."

The purpose of the rectifier in a welding set's electrical circuit is to convert AC (alternating current) to DC (direct current). This is important because welding typically requires a steady and constant flow of current in one direction. By converting AC to DC, the rectifier ensures a consistent and reliable power source for the welding process, allowing for more accurate and controlled welds.

The correct answer is "Check- gas flow rate, stick out length, WFS, and current." When calibrating a mechanized MAG welding plant, it is important to check the gas flow rate to ensure proper shielding gas coverage. Stick out length refers to the length of the electrode extending from the welding torch and should be checked to maintain the correct arc length. Wire feed speed (WFS) is crucial in controlling the deposition rate, and current is adjusted to achieve the desired heat input. Therefore, all of these factors need to be checked during the calibration process.

Aluminium oxide residue is formed on the surface of aluminium during welding. This residue acts as a barrier and makes it more difficult to melt the aluminium. Therefore, more heat is required to melt the aluminium oxide residue compared to the aluminium itself. This can affect the welding process as it may require higher temperatures or longer welding times to achieve proper fusion.

In a semi-automatic welding process, 100% CO2 would normally give the deepest penetration on steel. CO2 has a higher heat input compared to argon and the mixture of argon and CO2, which allows for deeper penetration into the steel. Argon and the mixture of argon and CO2 may be used for different purposes in welding, but in terms of achieving the deepest penetration, 100% CO2 is the most suitable choice.

A concave fillet weld with a throat thickness of 6mm would have the highest resistance to fatigue fractures compared to the other options. The concave shape of the weld helps to distribute stress more evenly, reducing the concentration of stress at any particular point. Additionally, the smaller throat thickness of 6mm allows for better penetration and fusion between the base metal and the weld, resulting in a stronger joint.

E7018 electrodes are basic low hydrogen electrodes containing iron powder. Additionally, they are known for depositing weld metal with a tensile strength of at least 70,000 psi (pounds per square inch). This classification (E7018) refers to a type of MMA (Manual Metal Arc) electrode that is commonly used in welding applications. It is classified as "basic" because it contains a basic flux coating, which helps to protect the weld from impurities and contaminants. It is also classified as "low hydrogen" because it has a low moisture content, which reduces the risk of hydrogen-induced cracking in the weld. The addition of iron powder helps to improve the deposition rate and overall performance of the electrode.

When the arc length is shortened in an MMA welding plant, the voltage will decrease. This is because the arc length is inversely proportional to the voltage. When the arc length is reduced, the voltage required to maintain the arc decreases. As a result, the voltage will decrease in order to maintain a stable welding process.

In semi-automatic welding processes, the welder manually controls the travel speed and arc gap, while the welding plant automatically feeds the filler metal. This allows for greater control and precision compared to fully automatic processes where the welding plant controls all aspects of the weld.

A change of pipe wall thickness by at least 15 mm is the most likely to be considered an essential variable for a welder qualification test because it involves a significant change in the welding conditions. This change in pipe wall thickness can affect the heat input, welding technique, and overall weld quality, making it crucial for a welder to demonstrate their ability to adapt to different thicknesses. The other options mentioned in the question may also be important variables to consider, but a change in pipe wall thickness is typically a more critical factor in welder qualification tests.

The Charpy Vee notch impact test is a destructive test that is used to give a measure of notch toughness in a material. It assesses the material's ability to absorb energy in the presence of a notch or defect. This test is commonly used to evaluate the ductility and toughness of materials, including those in the weld zone. Therefore, both statement a and c are true.

When using pure argon as the shielding gas in MIG welding on carbon steel, excessive root penetration and porosity are likely to occur. Excessive root penetration refers to the weld penetrating too deeply into the base metal, which can weaken the joint. Porosity refers to the presence of small gas pockets within the weld, which can also weaken the joint and make it more prone to cracking. Using pure argon as the shielding gas can lead to these issues because it does not provide enough oxygen to promote proper weld penetration and prevent the formation of gas pockets.

In an MMA welding process, the statement that is false is "An arc gap, which remains almost constant even if as usual the welder varies the position of the electrode." In reality, the arc gap will vary depending on the position of the electrode. The voltage and current, on the other hand, will remain almost constant even if the arc gap is varied by the welder. Therefore, the correct answer is "a and b."