This article is about WELDING & PIPING INTERVIEW QUESTIONS PART-2 as per international codes and standards and useful for Welding and piping engineers, QCs, Supervisors and managers.
WELDING & PIPING INTERVIEW QUESTIONS
1. Describe the difference between QA & QC?
Quality Control (QC) refers to the operational techniques such as inspection, examination, and testing that are utilized to ensure that a product or service meets the defined quality requirements. QC focuses on detecting and correcting any deviations or defects in the final product or service. It is primarily concerned with the verification and validation of the product or service against established standards.
On the other hand, Quality Assurance (QA) is the system of actions and planning implemented to provide confidence that a product or service will consistently meet the required quality standards. QA takes a proactive approach by establishing processes, systems, and procedures to prevent defects or issues from occurring in the first place. It involves the development and implementation of quality management systems, documentation, audits, and continuous improvement efforts to ensure that the necessary controls and processes are in place for consistent quality.
2. What do quality system audits evaluate?
Quality system audits evaluate the degree of conformance of a quality system to established requirements. These audits assess whether the quality system is designed, implemented, and maintained in accordance with specified standards, regulations, or internal policies and procedures. The purpose of a quality system audit is to verify that the quality management system is effectively addressing quality objectives, meeting customer requirements, and complying with relevant quality standards.
During a quality system audit, auditors typically examine various aspects of the quality system, which may include:
- Documentation and Procedures: Auditors review the documentation and procedures related to the quality system, such as quality manuals, standard operating procedures (SOPs), work instructions, and records. They assess whether these documents are properly developed, implemented, and maintained.
- Compliance: Auditors assess whether the quality system adheres to applicable standards, regulations, and requirements. This includes verifying compliance with industry-specific standards (e.g., ISO 9001) and regulatory requirements (e.g., FDA regulations for medical devices).
- Process Effectiveness: Auditors evaluate the effectiveness of key processes within the quality system, such as risk management, change control, corrective and preventive actions (CAPA), internal audits, and supplier management. They assess whether these processes are adequately designed, implemented, and monitored to achieve desired outcomes.
- Training and Competence: Auditors may review training programs and assess the competence of personnel involved in the quality system. They verify that employees have the necessary qualifications, training, and skills to perform their roles effectively.
- Performance Monitoring: Auditors examine the methods and metrics used to monitor and measure the performance of the quality system. This includes assessing the effectiveness of quality control activities, data analysis, and the use of key performance indicators (KPIs) to track quality objectives.
- Continuous Improvement: Auditors assess whether the quality system includes mechanisms for continuous improvement. This involves evaluating processes for identifying and addressing non-conformances, conducting root cause analysis, implementing corrective actions, and fostering a culture of continual improvement.
Overall, quality system audits provide an independent evaluation of the extent to which a quality system meets established requirements, enabling organizations to identify areas of improvement and ensure ongoing compliance with quality standards.
3. Does Saudi Aramco follow international quality system or not?
The basic elements of an ISO 9000 Series Quality Program, as per the ISO 9000 standards adopted by Saudi Aramco, include the following components:
- Quality Management and Quality Assurance Standards (ISO 9000):
The ISO 9000 series provides a set of international standards and guidelines for quality management and quality assurance. These standards establish the fundamental principles and concepts of quality management systems and provide a common language for organizations to understand and communicate about quality-related matters. The ISO 9000 standards include ISO 9001, ISO 9002, and ISO 9003, which specify the requirements for quality management systems and provide guidelines for their implementation. - Quality Systems (ISO 9001, 9002, 9003):
ISO 9001, ISO 9002, and ISO 9003 are the core standards within the ISO 9000 series that define the requirements for establishing, implementing, and maintaining quality management systems. These standards outline the necessary elements and processes for ensuring that organizations consistently meet customer requirements, enhance customer satisfaction, and continually improve their quality performance. ISO 9001 is the most comprehensive standard, covering all aspects of quality management, while ISO 9002 and ISO 9003 are specific variations tailored to different types of organizations or situations. - Quality Plan Guidelines (ISO 10005):
ISO 10005 provides guidelines for the development, implementation, and maintenance of a quality plan. A quality plan is a documented approach that outlines the specific quality objectives, strategies, and activities for a particular project, process, or organization. It serves as a roadmap for managing quality throughout the lifecycle of a project or process and provides a framework for ensuring that quality requirements are met.
By adopting the basic framework and definitions of the ISO 9000 series, Saudi Aramco aims to establish a common understanding and improve communication with prospective contractors whose quality systems align with ISO 9000 standards. This adoption helps create a universal language and framework for quality management, ensuring that both the company and contractors have a consistent approach to quality assurance and can effectively collaborate in meeting quality requirements.
It’s important to note that the ISO 9000 series encompasses additional standards and guidelines beyond the mentioned elements, such as ISO 9004 (providing guidance for performance improvement), ISO 19011 (guidance for auditing quality management systems), and others. The specific elements and implementation of an ISO 9000 series Quality Program can vary depending on the organization’s context, industry, and specific requirements.
4. What is an essential variable as related to a Weld Procedure Specification (WPS)?
An essential variable in a Weld Procedure Specification (WPS) refers to a welding condition that, when changed, can significantly impact the mechanical properties of the weld. These variables are crucial because they affect the quality and performance of the welded joint. Essential variables are identified and specified in the WPS to ensure consistent and reliable welding processes.
Examples of essential variables include the welding process, welding position, base material thickness, filler material, preheat and interpass temperature, and welding energy parameters. Changes to these variables may require revising the WPS or conducting qualification testing to ensure the desired mechanical properties of the weld are maintained.
6. Heat input (SMAW per ASME IX) is a combination of what two electrical characteristics & travel speed?
Heat input in Shielded Metal Arc Welding (SMAW), as defined by ASME IX (ASME Boiler and Pressure Vessel Code, Section IX), is a combination of two electrical characteristics, which are voltage and amperage, along with the travel speed.
Voltage refers to the electrical potential difference applied between the welding electrode and the workpiece. It determines the arc length and influences the heat generated during the welding process. Higher voltage settings result in a longer arc length and increased heat input.
Amperage, also known as current, represents the flow of electrical charge through the welding circuit. It determines the amount of heat generated by the arc. Higher amperage settings produce more heat and can result in a higher heat input.
Excessive heat input during the Shielded Metal Arc Welding (SMAW) process is mainly attributed to poor welding techniques, such as excessively wide weaving and slow travel speed.
7. What are three possible sources of hydrogen encountered during the Shielded Metal Arc Welding (SMAW) process?
Three potential sources of hydrogen encountered during the SMAW process include moisture present in the metal and electrode coating, oil contamination, and elemental hydrogen within the base metal.
8. What are some possible causes of porosity in carbon steel welds during the Shielded Metal Arc Welding (SMAW) process?
Several likely causes of porosity in carbon steel welds using the Shielded Metal Arc Welding (SMAW) process include poor welding technique and equipment, excessive wind, presence of moisture, and weld contaminants.
9. What measurement is used to determine the size of a concave fillet weld?
The dimension measured to determine the size of a concave fillet weld is the throat.
10. Which measurement is used to determine the size of a convex fillet weld?
The dimension measured to determine the size of a convex fillet weld is the leg length.
11. In a single pass weld, where is the most likely location for cracking to occur due to excessive current input?
Cracking is most likely to occur along the centerline of the weld from excessive current input in a single pass weld.
12. What are the consequences of not implementing proper purging/back gassing during the Gas Tungsten Arc Welding (GTAW) process on stainless steel material?
When the Gas Tungsten Arc Welding (GTAW) process is performed on stainless steel material without proper purging or back gassing, oxidation can occur at the inner diameter (ID) of the weld. This phenomenon is commonly referred to as “sugaring.”
Sugaring happens when the backside of the weld, which is exposed to ambient air, lacks adequate shielding gas protection. As a result, oxygen reacts with the high-temperature weld metal, leading to the formation of oxides. These oxides appear as a rough, grainy, and discolored surface at the ID of the weld.
13. Which three mechanical tests, out of the five available, are employed for procedure and performance qualifications according to ASME IX?
Three of the mechanical tests employed for procedure and performance qualifications in ASME IX are:
- Tension test
- Guided bend test
- Fillet-weld test
- Notch-toughness & Stud-weld tests
14. What is the procedure for performing Magnetic Particle inspection of a weld using the wet continuous test method?
During the Magnetic Particle Inspection of a weld using the wet continuous test method, the process is performed as follows:
- Particles Application: Fluorescent particles are sprayed, poured on, or applied by immersion onto the surface of the weld.
- Magnetizing Current: The magnetizing current is then applied while the particles are still in motion or flowing on the surface of the weld.
By applying the magnetizing current while the particles are in motion, any magnetic leakage or defects in the weld will cause the particles to gather and form visible indications. These indications can be detected and examined under suitable lighting conditions to identify any potential defects, such as cracks or discontinuities, in the weld.
The wet continuous test method is a widely used technique for magnetic particle inspection, providing an efficient and effective means of detecting surface and near-surface defects in welds.
15. True/false: Indications with Liquid Penetrant Testing are easily seen if the surface has been prepared by grinding prior to testing?
Answer: False
Grinding the surface prior to Liquid Penetrant Testing can actually impede the visibility of indications. Grinding can cause smearing of metal, which can mask or cover up discontinuities or defects that would otherwise be detectable. The process of grinding can result in a smoother surface, closing or filling in surface discontinuities, and making them more difficult to detect during the Liquid Penetrant Testing. Therefore, it is important to avoid grinding or any other surface preparation that can interfere with the detection of indications during Liquid Penetrant Testing.
16. Which NDT method and technique use a reflected sound beam to perform volumetric examination of welds?
An NDT method and technique that employs a reflected sound beam for the volumetric examination of welds is Ultrasonic Testing using the Shear Wave Technique. This technique allows for thorough coverage and examination of the weld volume to detect any internal flaws or discontinuities.
17. What are three drawbacks of Radiographic Testing (RT) in comparison to other NDT methods?
Three disadvantages of Radiographic Testing (RT) compared to other NDT methods are:
- Radiation Safety Precautions: RT involves the use of ionizing radiation, which requires strict safety precautions to protect personnel from exposure. This includes the need for radiation shielding, proper training, and adherence to safety regulations.
- Planar Defects Not Readily Detectable: RT is less effective in detecting planar defects, such as cracks or delaminations, compared to other NDT methods like Ultrasonic Testing or Magnetic Particle Testing. Planar defects can be difficult to visualize on radiographic images, making their detection challenging.
- Heavy Equipment: RT typically requires the use of heavy and bulky equipment, including X-ray machines or gamma-ray sources, as well as specialized film or digital imaging systems. This can make the setup and transportation of equipment more cumbersome and time-consuming compared to some other NDT methods.
It’s worth noting that while RT has these disadvantages, it also offers unique advantages in certain applications, such as its ability to penetrate thick materials and provide a permanent record in the form of radiographic images. The selection of an appropriate NDT method depends on the specific requirements and limitations of the inspection task.
18. Why is it important to use exactly the same Radiographic Testing (RT) procedure before and after stress relieving when a product is to undergo stress relief?
Answer: By using the same RT procedure before and after stress relieving, it allows for a baseline evaluation of the product’s initial condition. This is crucial to ensure that any indications or defects detected before stress relieving are accurately compared and evaluated after the process. It helps prevent misinterpretation of borderline indications that may be affected by the stress relieving process, allowing for a more accurate assessment of the product’s condition and ensuring the reliability of the inspection results.
19. What is the most probable indication when a dark narrow area, approximately 2-3mm wide, appears along the edge of the weld area on a radiograph of a joint with a 60-degree double-vee groove?
The indication most likely to be represented by a dark narrow area, 2-3mm wide, appearing along the edge of the weld area on a radiograph with a 60-degree double-vee groove joint is an external undercut.
20. What is the most likely indication when a localized darker density radiographic image with fuzzy edges appears in the center of the width of the weld image, which may or may not be wider than the width of the root pass image?
Answer: The indication most likely to be represented by such radiographic image characteristics is burn-through.
21. What are five common film artifacts that may lead to the rejection of radiographic film?
Here are five common film artifacts that may be cause for rejection of radiographic film:
- Film Scratches: Physical scratches on the film surface that can obscure or distort the image.
- Light Leaks: Unwanted exposure to light, resulting in areas of excessive density or fogging on the film.
- Chemical Stains: Stains caused by improper chemical processing, leading to localized areas of abnormal density or discoloration.
- Fogged Film: Overall or localized increase in film density, reducing image contrast and clarity, often caused by light exposure or improper storage.
- Static Marks: Marks or streaks caused by static electricity during film handling or processing, resulting in abnormal density patterns.
Please note that there are additional film artifacts that may also lead to rejection of radiographic film, such as water marks, streaks, crimp marks, finger marks, lint, and dirt.
22. What is the term used to describe the type of exposure where the radiation source is located inside the piping and the film is located outside, with a single-wall exposure and single-wall view?
Answer: This type of exposure is commonly referred to as “panoramic” exposure.