Q1) When considering the MIG/MAG welding process which of the following metal transfer modes would be the most suited to the welding of thick plates over 25mm, flat welding position?
- Dip transfer
- Pulse transfer
- Spray transfer
- Globular transfer
(Explanation: Spray transfer is often preferred for welding thick plates in the flat position due to its high deposition rates, good penetration, and overall efficiency. While pulsed transfer can also be effective, spray transfer is a common choice for thicker materials in flat welding positions.)
Q2) Poor penetration would be found in MIG/MAG welded steels when using:
- Argon + 20 % CO2
- CO2
- Pure Argon
- Argon + 5 % CO2
(Explanation: Pure Argon tends to produce a wider, shallower penetration profile, and in certain applications, it may result in poor penetration. The addition of CO2 helps improve the welding process by providing better arc stability and deeper penetration.)
Q3) In the TIG welding process, slope-in/slope-out capability is useful in order to:
- Avoid start porosity and crater pipes
- Reduce the risk of tungsten inclusions
- Stabilise the arc
- Allow more time for the filler metal to melt
(Explanation: In TIG welding, slope-in and slope-out capability, also known as “amperage ramping” or “current up/down slope,” is useful to avoid start porosity and crater pipes. Slope-in helps gradually increase the welding current at the start of the weld to avoid porosity, and slope-out gradually decreases the current at the end to prevent the formation of crater pipes. This feature helps in achieving smoother and more controlled starts and stops in the welding process.)
Q4) Which defect is NOT normally associated with TIG?
- Tungsten inclusion
- Crater pipe
- Spatters
- Lack of fusion
(Explanation: Spatters are normally not associated with TIG (Tungsten Inert Gas) welding. TIG welding typically produces a clean and precise weld with minimal spatters compared to processes like MIG (Metal Inert Gas) welding, which is more prone to spatter.)
Q5) Argon purging on the root side is necessary in the TIG welding of stainless steel to:
- Obtain full penetration
- Obtain full fusion
- Avoid porosity in the root
- Obtain a satisfactory weld surface finish
(Explanation: Argon purging on the root side in TIG welding of stainless steel is necessary to avoid porosity in the root. Purging with argon creates an inert atmosphere on the backside of the weld, preventing the formation of porosity caused by exposure to oxygen.)
Q6) Tungsten inclusion occur due to:
- High current
- Incorrect vertex angle
- Lack of welder skill
- All of the above
(Explanation: Tungsten electrodes are not consumed during welding. However, sometimes the tungsten melts and go inside the molten weld pool, which results in tungsten inclusion. Tungsten inclusion can occur due to various factors, including an incorrect vertex angle, high current, and a lack of welder skill. Each of these factors can contribute to the presence of tungsten particles in the weld, leading to tungsten inclusion.)
Q7) In MAG/CO2 welding which parameter gives the greatest control of weld appearance during dip transfer or short-circuiting welding?
- Wire stick-out length
- Amperage
- Wire feed speed
- Inductance
(Explanation: Inductance control, if available on the welding equipment, can influence the characteristics of the welding arc, affecting things like arc stability and control of the molten metal transfer. Adjusting the inductance can have an impact on the appearance of the weld.)
Q8) What type of current is used for TIG welding of carbon steels:
- DCEN
- AC
- DCEP
- None of the above
(Explanation: DCEN, or straight polarity, is commonly used for TIG (Tungsten Inert Gas) welding of carbon steels. In this configuration, the electrode (tungsten) is connected to the negative terminal, and the workpiece is connected to the positive terminal.)
Q9) Spatter may be finely controlled during MIG/MAG (GMAW) welding by:
- Adjusting the inductance control
- Using CO2 gas
- Increasing the arc voltage
- Welding with no gas
(Explanation: The inductance control is a parameter that can be adjusted on some welding machines to influence the welding process, and it plays an important role in controlling spatter. Inductance control on a welding machine regulates the rate of current rise and fall during the welding process. By adjusting the inductance control, one can influence the characteristics of the welding arc.)
Q10) Which of the following electrodes and current types may be used for the TIG welding of nickel and its alloys?
- Cerium electrode, DC –ve
- Zirconium electrode, AC
- Thorium electrode, DC +ve
- All of the above may be used
(Explanation: When TIG welding, nickel and its alloys, a zirconium electrode with AC (alternating current) is commonly used. The use of AC helps to maintain a stable arc and provides good penetration and cleaning action on the base metal, which is beneficial for welding nickel alloys.)
Q11) The main reason why the use of semi-automatic dip transfer MIG/MAG welding is prohibited for some high-integrity applications is because?
- It may produce a lot of spatter
- The weld metal toughness is always poor
- It very often gives lack of sidewall fusion defects
- Wire feeding problems mean there are usually far too many stop-start regions
(Explanation: The semi-automatic dip transfer mode in MIG/MAG welding is characterized by the intermittent transfer of molten metal in the form of droplets from the welding wire to the weld pool. The reason why it is often prohibited for high-integrity applications is that it can very often result in a lack of sidewall fusion defects.)
Q12) Which of the following current types would be used for welding aluminum with the TIG welding process?
- AC
- DC +ve electrode
- DC –ve electrode
- All of the above could be used successfully
(Explanation: AC is effective for welding aluminum because it helps in cleaning the aluminum oxide layer from the surface during the welding process. This prevents oxide buildup on the tungsten electrode and contributes to better overall weld quality when working with aluminum.)
Q13) Which of the following welding processes would you expect to use a collet:
- TIG
- MIG / MAG
- MMA
- All of the above
(Explanation: A collet is commonly used in TIG (Tungsten Inert Gas) welding. Collet is the part of the torch assembly and is responsible for holding and securing the tungsten electrode. The collet exerts pressure on the electrode, keeping it in place while allowing for adjustments and replacements as needed.)
Q14) The spray transfer mode of GMAW is characterized by……..
- Giving deep penetration
- Being suitable for positional welding
- Giving excessive spatter
- All of the above
(Explanation: In the spray transfer mode, the welding wire is typically charged with high current, and the metal transfer occurs in a spray-like fashion. This mode is often used in applications where deep penetration into the base metal is required.)
Q14) In positional MMA welding (SMAW) on pipework, welders are having difficulty in obtaining good capping profiles when welding in the overhead position. You would..
- Advise them to increase the current
- Advise them to increase the voltage
- Ask for a new welding team
- Suggest the use of a smaller diameter electrode
(Correct Answer: d. Suggest the use of a smaller diameter electrode.
A smaller diameter electrode can offer better control and deposition of weld metal in positional welding. It allows for more precise placement of the filler metal, making it easier to achieve a desirable capping profile, especially in challenging positions like overhead welding.
Conflict: b. Advise them to increase the voltage.
Increasing the voltage is often a more common and straightforward adjustment to improve wetting and fusion of the weld metal, especially in overhead welding positions. It can help achieve better capping profiles by promoting smoother and more consistent deposition.
So, both Option b and Option d can be relevant suggestions to address the issue. The choice between the two may depend on the specific welding conditions and the welder’s preference or experience.)
Q15) MMA electrode can be grouped into three main types. These are:
- Basic, Cellulosic and Rutile
- Neutral, Cellulosic and Rutile
- Basic, Cellulosic and neutral
- None of the above
(Explanation: Basic, Cellulosic & Rutile is a grouping of MMA Welding (SMAW) based on their flux coverings. Examples are;
- Basic Electrode Example: E7018
- Cellulosic Electrode Example: E6010
- Rutile Electrode Example: E6013)
Q16) Which of the following welding processes would give the highest heat input when using typical parameters?
- Tungsten Inert Gas welding
- Manual Metal Arc welding
- Submerged Arc welding
- Metal Active Gas welding
(Explanation: The continuous feeding of the electrode and the use of granular flux contribute to sustained and intense heat, making SAW effective for welding thick materials and achieving deep penetration)
Q17) The term “low hydrogen electrode” is often used for certain electrodes. What type of covering will they have?
- Cellulosic
- Rutile
- Basic
- Acid
(Explanation: The term “low hydrogen electrode” is often associated with electrodes that have a basic covering. These electrodes are designed to deposit weld metal with low levels of hydrogen, which is crucial for preventing hydrogen-induced cracking in the weld metal. Basic-coated electrodes are often used in applications where hydrogen-induced cracking is a concern, such as welding high-strength steels and critical applications.)
Q18) MMA welds made with damaged electrode coatings are subject to:
- Porosity
- Undercut
- Excessive penetration
- Excessive bead height
(Explanation: Damage electrode coating can lead to contamination and the release of gases during welding, resulting in porosity in the weld. Porosity is the formation of small cavities or voids within the weld metal, and it can weaken the weld and adversely affect its mechanical properties.)