Interview Questions for LNG Inspection

My experience encompasses a wide range of LNG inspection techniques, both visual and non-destructive. Visual inspection forms the foundation, allowing for the identification of readily apparent defects like cracks, dents, or significant corrosion. However, the true depth of assessment comes from non-destructive testing (NDT). I’m proficient in several NDT methods, including:

• Ultrasonic Testing (UT): This is crucial for detecting internal flaws, like cracks or laminations, in the tank walls and piping. Think of it as a sonic echolocation – we send sound waves into the material and analyze the reflections to pinpoint hidden defects. I’ve used UT extensively on both membrane and prismatic LNG tanks.

• Radiographic Testing (RT): RT, using X-rays or gamma rays, allows us to see internal structures and flaws, revealing things UT might miss, especially in welds. It’s particularly important for assessing the integrity of critical welds in LNG containment systems. I’ve personally overseen numerous RT inspections, ensuring compliance with stringent safety regulations.

• Magnetic Particle Testing (MT): Primarily used for detecting surface and near-surface cracks in ferromagnetic materials, MT is invaluable for inspecting welds and components made of steel. Imagine sprinkling iron filings onto a magnetized surface; the filings will cluster around any cracks, making them easily visible. I’ve used this technique to evaluate the condition of various valves and fittings.

• Liquid Penetrant Testing (PT): This surface inspection method identifies cracks and other surface-breaking defects by using a dye that penetrates the defect and is then revealed by a developer. Think of it like revealing a fingerprint. It’s a simple but effective technique useful in various components of the LNG plant.

I’ve also been involved in advanced techniques such as phased array UT and advanced RT techniques such as digital radiography for improved data analysis and reporting.

NDT is absolutely critical in LNG inspection because it allows us to assess the structural integrity of the equipment without causing damage. LNG storage and transport involves extremely low temperatures and high pressures, demanding impeccable integrity to prevent catastrophic failures, which could lead to significant environmental damage and loss of life. NDT techniques enable the early detection of subtle defects – corrosion, cracks, or material degradation – that might be invisible to the naked eye. This proactive approach enables timely repairs or replacements, preventing costly and potentially dangerous incidents. Think of it as a crucial preventative maintenance strategy. For example, discovering a small crack early with UT can prevent it from propagating and eventually leading to a tank rupture. The cost of replacing a tank far outweighs the cost of an NDT inspection.

Common defects found during LNG tank inspections vary depending on the tank type (membrane, prismatic) and its age, but some frequently encountered problems include:

• Corrosion: This is perhaps the most significant concern, particularly in areas exposed to moisture or chemical attack. It can range from localized pitting to widespread thinning of the tank walls.

• Cracking: Stress corrosion cracking (SCC) and fatigue cracking are prevalent issues. SCC occurs when a combination of stress and a corrosive environment weakens the material. Fatigue cracks develop due to repeated cycles of stress.

• Weld defects: Imperfections in welds, such as porosity, lack of fusion, or cracks, are critical issues that NDT helps identify and assess.

• Dents and deformations: These can weaken the tank structure and compromise its integrity, especially in areas subjected to impacts.

• Material degradation: Over time, materials can degrade due to low temperature embrittlement, leading to a reduction in their strength and ductility. This is especially important in considering the lifetime of the plant and materials used.

The severity of these defects is determined by their size, location, and orientation within the tank structure, and the resulting risk to operational safety. Our evaluation also considers the remaining material thickness, the type of material and other factors.

Corrosion identification and assessment in LNG equipment involves a multi-pronged approach. Visual inspection is the first step, looking for signs like rust, pitting, or discoloration. However, visual inspection alone is insufficient to determine the extent of corrosion. I utilize NDT techniques, primarily UT and RT, to accurately measure the depth and extent of corrosion. UT provides precise thickness measurements, allowing us to determine the remaining wall thickness and compare it to allowable minimum thicknesses defined in relevant codes and standards (like ASME Section VIII). RT helps visualize corrosion in areas that are difficult to access with UT. We typically use a combination of these methods, especially for complex geometries or in welds. We also consider the environmental factors and the history of the equipment, including operational parameters and maintenance records, to better understand the corrosion mechanisms and predict future corrosion rates.

An example: During an inspection, we discovered localized pitting corrosion in a section of LNG piping. Using UT, we precisely measured the depth of the pits and the remaining wall thickness. Based on these measurements and the applicable codes, we determined the extent of the corrosion and recommended either repair or replacement of the affected section.

Safety is paramount during LNG inspections. LNG is cryogenic, meaning it’s extremely cold, posing risks of frostbite and equipment failure. The environment also presents a potential for asphyxiation due to the displacement of oxygen. We follow a strict safety protocol that includes:

• Personal Protective Equipment (PPE): This includes specialized cold-weather clothing, safety glasses, gloves, and respiratory protection.

• Confined Space Entry Procedures: Many inspections require entry into confined spaces, necessitating appropriate permits, atmospheric monitoring, and rescue procedures.

• Gas Detection: Continuous monitoring of the atmosphere for oxygen deficiency and the presence of flammable gases is crucial.

• Emergency Procedures: Clear emergency procedures must be in place, including evacuation plans and emergency contact information.

• Lockout/Tagout Procedures: Proper lockout/tagout procedures must be followed to ensure that equipment is de-energized and isolated before any inspection work is performed.

• Training and Competency: All personnel involved in the inspection must be adequately trained and competent in handling the risks associated with LNG and the specific NDT techniques used.

Regular safety briefings and toolbox talks reinforce the importance of safety and ensure everyone understands their roles and responsibilities.

Codes and standards like ASME (American Society of Mechanical Engineers) and API (American Petroleum Institute) provide the framework for safe and reliable design, construction, and operation of LNG facilities. These codes specify material requirements, fabrication techniques, inspection procedures, and acceptance criteria. For example, ASME Section VIII, Division 1, covers the design and construction of pressure vessels, which are crucial components of LNG storage tanks. API standards address specific aspects of LNG handling, storage, and transportation. During inspections, I meticulously ensure compliance with the relevant codes and standards. This ensures that the equipment meets the required safety and performance standards. Any deviations from these codes are carefully documented and addressed through appropriate corrective actions. This adherence to industry standards is vital for ensuring the integrity and safety of LNG facilities.

Inspection findings are documented meticulously and presented in a clear, concise report. The report includes:

• A summary of the inspection scope and methodology: This outlines the specific areas inspected, the NDT techniques used, and the personnel involved.

• Detailed descriptions of any defects found: This includes the type, size, location, and orientation of each defect, supported by photographic or digital evidence from NDT.

• Assessment of the significance of each defect: This considers the defect’s severity, its potential impact on the integrity of the equipment, and its implications for ongoing operation.

• Recommendations for corrective actions: This includes suggestions for repairs, replacements, or further investigations.

• Compliance with relevant codes and standards: This section confirms adherence to the appropriate standards and highlights any deviations found.

The report is tailored to the specific audience – operators, engineers, management – using clear language and avoiding unnecessary technical jargon. The reports are critically reviewed before distribution to ensure accuracy and clarity, and to help facilitate informed decision-making regarding the equipment’s condition and its continued operation.

Cryogenic testing and inspection are crucial for ensuring the integrity of LNG facilities and equipment, which operate at extremely low temperatures (-162°C). My experience encompasses a wide range of tests, including visual inspections for cracks, leaks, and corrosion; ultrasonic testing (UT) to detect subsurface flaws; radiographic testing (RT) for weld integrity assessment; and leak detection using specialized equipment like helium leak detectors. I’ve worked on various components, from storage tanks and pipelines to vaporizers and pumps, always adhering to stringent safety protocols and industry standards like ASME Section VIII, Div. 1 and API standards.

For instance, during an inspection of an LNG vaporizer, we discovered a hairline crack in a critical weld using UT. This was promptly reported and led to a successful repair, preventing a potential major incident. Understanding the unique challenges of cryogenic materials and their behaviour at these low temperatures is paramount in ensuring accuracy and preventing misinterpretations.

My experience with LNG storage tank inspections includes both internal and external inspections of double-walled and membrane tanks, using a variety of non-destructive testing (NDT) methods. External inspections focus on identifying corrosion, insulation degradation, and any signs of ground settlement or structural issues. Internal inspections are more complex, often requiring confined space entry and specialized equipment for accessing difficult-to-reach areas. We meticulously document all findings using high-resolution photography, detailed inspection reports, and 3D scanning technology to create accurate digital twins of the tank’s condition.

A memorable experience involved inspecting a large double-walled LNG storage tank. Using a combination of UT, RT and advanced 3D laser scanning techniques, we detected minor corrosion in the inner tank wall in an area with poor insulation. The early detection allowed for targeted repairs, avoiding a costly and potentially hazardous situation later.

Effective management of inspection data and documentation is critical for maintaining compliance and ensuring the long-term integrity of LNG assets. We utilize a combination of computerized maintenance management systems (CMMS) and dedicated inspection software to manage this data. All inspection reports, NDT results, and photographs are meticulously documented, linked to specific equipment and locations, and stored securely. We maintain a robust version control system and adhere to strict data management protocols to ensure data integrity and traceability. Regular audits and data backups are performed to mitigate risks of data loss.

Data analysis is also an important part of the process. We use this data to track trends, predict maintenance needs, and optimize inspection strategies, leading to cost savings and enhanced safety. This data-driven approach allows for proactive maintenance rather than reactive responses.

LNG transportation and handling safety are paramount, demanding meticulous adherence to international standards and regulations. This encompasses all aspects of the supply chain, from production and liquefaction to transportation, storage, and regasification. Key safety considerations include preventing leaks (which can cause fires or explosions), mitigating the risks associated with cryogenic temperatures (cold burns, frostbite), and ensuring safe handling of the highly flammable LNG. Specialized training for personnel, emergency response plans, and robust safety management systems are essential.

For example, proper venting systems are crucial to manage pressure build-up and prevent potential over-pressurization incidents. Additionally, stringent procedures for loading and unloading LNG carriers are necessary to prevent spills and maintain the integrity of the vessels and terminals.

Onshore and offshore LNG inspections differ significantly due to the different environmental conditions and accessibility challenges. Onshore inspections are generally easier to conduct, with better access to equipment and facilities. However, the sheer scale of onshore facilities can make inspections more time-consuming. Offshore inspections present unique challenges, including harsh weather conditions, limited accessibility, and the need for specialized equipment and trained personnel for offshore operations. Safety protocols are even more stringent offshore due to the remoteness and potential for serious consequences in case of an incident.

For instance, inspecting offshore LNG pipelines requires specialized remotely operated vehicles (ROVs) or divers for underwater inspections, while onshore pipelines can be inspected using more readily available methods such as ground penetrating radar.

My experience includes inspections of various LNG vessel types, including membrane-type LNG carriers (MTLCs), Moss-type LNG carriers, and other specialized LNG carriers. Each type presents unique design and construction features, requiring specific inspection approaches. Inspections focus on hull integrity, cargo containment systems, insulation, and other critical components, with emphasis on safety equipment and procedures. Understanding the specific design and operational characteristics of each vessel type is crucial for ensuring thorough and effective inspections.

For example, inspections of membrane-type LNG carriers focus on the integrity of the membrane containment system, which plays a critical role in preventing LNG leaks. This often involves advanced NDT techniques to detect any thinning or damage to the membrane.

Common challenges during LNG inspections include the extreme cryogenic temperatures, which can impact the efficiency and accuracy of certain inspection methods. Access to confined spaces within storage tanks and vessels can also be difficult and potentially hazardous. Furthermore, the need to balance inspection thoroughness with operational requirements can be challenging, as prolonged shutdowns are costly. Maintaining compliance with constantly evolving regulations and standards also adds complexity. Finally, interpreting inspection data correctly and making accurate assessments requires extensive expertise and experience.

For example, the cold temperatures can affect the performance of ultrasonic transducers, requiring specialized equipment and calibration procedures. Careful planning and coordination with the operating company are essential to minimize downtime and ensure safety throughout the inspection process.

Disagreements with contractors or clients regarding inspection findings are handled professionally and transparently. My approach prioritizes collaboration and a data-driven resolution. First, I meticulously review the findings with all parties involved, ensuring everyone has access to the same data and understands the methodology used. If discrepancies persist, I initiate a structured discussion, presenting evidence such as photographic and video documentation, inspection reports, and relevant industry standards. I facilitate open communication, actively listening to all perspectives and addressing concerns.

If the disagreement can’t be resolved through discussion, I propose a third-party expert review or utilize established dispute resolution mechanisms outlined in the contract. The goal is always to reach a consensus based on factual evidence and industry best practices. For example, during an inspection of a cryogenic pump, we disagreed on the severity of a crack detected. By presenting detailed images and comparing the defect to industry standards, we ultimately reached agreement on the appropriate repair strategy.

My experience with LNG pipeline inspections encompasses various stages, from initial construction oversight to in-service inspections. I’ve participated in inspections using various non-destructive testing (NDT) methods, such as ultrasonic testing (UT) to detect subsurface flaws, radiographic testing (RT) for identifying internal defects, and magnetic particle testing (MT) for surface cracks. I’ve also been involved in pipeline integrity assessments, which involve reviewing historical data, analyzing operational parameters, and assessing external factors that might affect pipeline integrity like soil conditions and environmental factors. This includes identifying potential areas of concern like corrosion, stress concentration points, and potential third-party damage.

One significant project involved the inspection of a 48-inch diameter LNG pipeline that spanned a challenging geographical region. We used a combination of in-line inspection tools and external visual inspections to thoroughly assess the pipeline’s condition, identifying several areas requiring immediate attention such as minor pitting corrosion, which were addressed effectively, preventing costly failures.

My proficiency extends across a wide array of inspection tools and equipment, including but not limited to:

• Non-destructive testing (NDT) equipment: Ultrasonic flaw detectors, radiographic equipment (including real-time radiography), magnetic particle inspection units, liquid penetrant testing kits.
• Visual inspection tools: Borescopes, fiber optic cameras, high-resolution cameras with zoom capabilities, drones for aerial inspections.
• Specialized tools for LNG inspections: Cryogenic temperature sensors, leak detection equipment for both gaseous and liquid LNG.
• Software and data analysis tools: NDT data analysis software, asset management software for tracking inspection data and scheduling future inspections.

I’m adept at using these tools and interpreting the data they generate, ensuring accurate and reliable inspection reports. My experience includes working with both portable and stationary equipment in diverse environmental conditions.

LNG liquefaction is a complex process involving the cooling of natural gas to approximately -162°C (-260°F), converting it from a gaseous to a liquid state. This significantly reduces its volume, making it easier and more cost-effective to transport and store. The process typically involves several stages:

• Pre-treatment: Removing impurities like water, carbon dioxide, and sulfur compounds.
• Cooling: Using a series of heat exchangers to progressively reduce the gas temperature.
• Liquefaction: Employing a refrigeration cycle, often using propane or mixed refrigerant cycles, to achieve the necessary cryogenic temperature for liquefaction.
• Storage and Transfer: Storing the liquefied LNG in specialized cryogenic tanks and transferring it to ships or other storage facilities.

Understanding these processes is crucial for effective LNG inspection because it allows me to identify potential failure points within the liquefaction plant, such as leaks in cryogenic piping, malfunctioning compressors, or problems with heat exchanger integrity. I need this knowledge to assess the risks and prioritize inspection efforts.

Ensuring the integrity of LNG facilities is paramount due to the hazardous nature of LNG. My approach is multi-faceted and incorporates several key strategies:

• Regular Inspections: Implementing a comprehensive inspection program that includes both routine inspections and more specialized inspections based on risk assessments. These cover all aspects of the facility, from storage tanks and pipelines to processing equipment and safety systems.
• Non-Destructive Testing (NDT): Utilizing various NDT methods to detect potential defects without damaging the facility. This is particularly important for identifying corrosion, cracks, and other structural issues.
• Preventive Maintenance: Developing and implementing a robust preventive maintenance plan to address potential problems before they escalate into major issues. This involves regular equipment servicing and timely repairs.
• Safety Management Systems (SMS): Adhering to strict safety protocols and procedures to mitigate the risk of accidents and incidents. Regular safety audits and training are essential.
• Data Analysis and Management: Utilizing data from inspections, maintenance records, and operational data to track asset health and identify trends. This allows for proactive mitigation of risks and improved decision-making.

For example, regular inspections using UT of storage tanks can detect wall thinning due to corrosion. Early detection allows for timely repairs, preventing potential leaks and catastrophic failures.

Regulatory compliance is a cornerstone of LNG inspection. My experience encompasses working within various regulatory frameworks, including those defined by organizations such as the International Maritime Organization (IMO), and national regulatory bodies. I understand and apply relevant codes and standards, such as those related to pressure vessel design, cryogenic equipment, and pipeline safety. This involves meticulous documentation, ensuring all inspections are conducted according to established procedures and regulatory requirements.

For example, I am familiar with the requirements for conducting inspections on LNG carriers, adhering to the Gas Carrier Code (IGC Code) and relevant amendments. This includes familiarity with the documentation required to prove compliance and the appropriate actions to take when non-conformities are identified. It’s crucial to maintain detailed records of inspections, and any corrective actions taken to satisfy regulatory compliance and to help prevent future non-conformities.

Prioritizing inspections based on risk assessment is a critical aspect of effective LNG inspection management. I employ a structured approach:

• Hazard Identification: Identifying all potential hazards associated with the LNG facility and its components.
• Risk Analysis: Evaluating the likelihood and severity of each hazard. This might involve using qualitative or quantitative risk assessment methods such as Failure Mode and Effects Analysis (FMEA).
• Risk Ranking: Ranking hazards according to their risk levels, prioritizing those with higher risk scores.
• Inspection Planning: Developing an inspection plan that addresses the highest-risk areas first. This includes specifying the inspection methods, frequency, and acceptance criteria.
• Inspection Execution and Reporting: Conducting inspections according to the plan and documenting all findings thoroughly.

For instance, a large LNG storage tank with a history of minor corrosion would be prioritized over a newly installed pipeline section with minimal risk of failure. This approach ensures resources are allocated efficiently to the areas posing the greatest risk to safety and operational integrity.

Root cause analysis (RCA) in LNG inspection is crucial for preventing future incidents. It’s a systematic process to identify the underlying reasons for failures, defects, or near misses, going beyond simply identifying symptoms. My approach typically involves using a combination of techniques, including the ‘5 Whys’ method, fault tree analysis, and fishbone diagrams. For example, if we discover a leak in an LNG tank, simply fixing the leak isn’t sufficient. Using the ‘5 Whys’, we might ask: Why did the leak occur? (e.g., corrosion). Why was there corrosion? (e.g., inadequate protective coating). Why was the coating inadequate? (e.g., poor application). Why was the application poor? (e.g., lack of proper training). Why was there a lack of training? (e.g., insufficient budget for training). This allows us to address the systemic issues leading to the failure, preventing recurrence.

Fault tree analysis allows us to map out potential failure causes and their probabilities, helping prioritize corrective actions. Fishbone diagrams help visually organize potential contributing factors, promoting collaborative brainstorming. Ultimately, a thorough RCA ensures that corrective actions target the root cause, not just the symptoms, leading to safer and more efficient operations.

Continuous improvement in LNG inspection is vital for safety and operational efficiency. My contributions focus on several key areas. First, I actively participate in internal audits and reviews of inspection procedures, identifying areas for improvement and proposing revisions based on best practices and lessons learned from past incidents or near misses. This includes reviewing and updating inspection checklists, ensuring they are comprehensive and aligned with the latest industry standards and regulations.

Second, I actively seek out opportunities to learn about new inspection technologies and techniques. For example, staying updated on advancements in non-destructive testing (NDT) methods like advanced ultrasonics or phased array technology can significantly improve the accuracy and efficiency of inspections. This knowledge is then shared with the team through training sessions and workshops.

Finally, I promote a culture of open communication and feedback within the team. This includes encouraging team members to report any safety concerns or suggestions for improvement without fear of retribution. By fostering a collaborative environment focused on continuous learning and improvement, we can ensure that our LNG inspection practices remain at the forefront of safety and efficiency.

During a pre-voyage inspection of an LNG carrier, we detected unusually high levels of methane emissions from one of the cargo tanks. Initial investigations pointed to a potential leak in the tank’s inner shell, a serious safety concern. The challenge was locating the precise source of the leak in a cryogenic environment, which presents significant logistical and safety difficulties.

Our team decided on a multi-faceted approach. First, we employed advanced ultrasonic testing techniques to map the tank’s inner shell, searching for any indications of material degradation or cracks. Simultaneously, we used a specialized gas detection system capable of pinpoint accuracy to better identify the source of the methane emissions. This involved carefully monitoring various points in and around the tank, while ensuring the safety of the inspection team.

The combined efforts ultimately pinpointed a small crack in a weld joint near the tank’s bottom. This allowed for targeted repairs instead of an extensive and costly overhaul of the entire tank, minimizing downtime and risks. The successful resolution highlighted the importance of using a combined strategy, leveraging multiple NDT techniques and prioritizing safety during the process. This incident prompted a review of our pre-voyage inspection procedures to incorporate more thorough testing near weld joints in our checks. This experience showed the value of combining innovative NDT methods with meticulous planning in resolving complex LNG inspection issues.

Maintaining accurate records and documentation is paramount in LNG inspection. We utilize a combination of digital and physical records. All inspections are meticulously documented using digital reporting software, which allows for real-time data entry and generates comprehensive reports. These reports include details of the inspection date, time, location, personnel involved, specific equipment used, and all test results obtained, accompanied by photographs and videos as needed. Critical data points like temperature readings, pressure levels and measurements from NDT methods are captured with appropriate calibration verifications.

Physical records such as inspection checklists, NDT reports, and certificates of calibration are also maintained in a secure and organized manner, compliant with industry standards and regulations. The digital system is backed up regularly, ensuring data integrity and business continuity. A clear, traceable audit trail is maintained at all times, ensuring transparency and accountability. This rigorous record-keeping system is vital for compliance, quality assurance, and potential legal proceedings.

LNG cargo handling systems encompass a range of technologies and processes to safely and efficiently transfer LNG from ships to onshore storage facilities or other vessels. These systems generally include:

• Ship-to-shore systems: These involve a variety of loading arms, typically cryogenic flexible hoses or rigid pipes, connected to a jetty system. These systems must be carefully designed to accommodate the temperature fluctuations and potential expansion of LNG.
• Ship-to-ship transfers: This involves transferring LNG between two vessels at sea. This requires highly specialized systems designed to ensure safe connections and operations in dynamic sea conditions.
• Vaporization systems: These systems are used to convert LNG back into gaseous natural gas (GNG) for use in various applications. These systems are typically heat-exchanger-based and require careful management to ensure efficient operation.
• Storage tanks: These are typically double-walled cryogenic tanks designed to maintain the LNG at its ultra-low temperatures. The integrity of these tanks is crucial to preventing leaks and environmental damage.
• Pumps and compressors: These are used for transferring and regulating LNG flow within the handling system. These need to be specially designed for cryogenic applications.

My experience encompasses understanding the operational principles, safety features, and maintenance requirements of these various systems. I am familiar with the different standards and regulations governing their design, construction, and operation, and the potential hazards associated with each.

Pressure testing and leak detection are integral parts of LNG system inspections. Pressure testing involves pressurizing sections of the system to a specific level and monitoring for pressure drops, which indicate leaks. This is often done using inert gases, rather than LNG itself for safety reasons. Various methods exist depending on the component being tested: hydrostatic testing for pipework, pneumatic testing for vessels, etc. Leak detection techniques include ultrasonic leak detection, acoustic emission testing, and various types of gas detectors sensitive to methane or other LNG components.

My experience includes conducting and overseeing pressure testing of various LNG systems and components, interpreting test results, and documenting all findings thoroughly. This is done according to stringent safety protocols to prevent the risks associated with high pressures and cryogenic fluids. I am proficient in using various leak detection instruments and interpreting the data they provide to locate and quantify leaks.

For example, during a pressure test on a new LNG storage tank, we utilized ultrasonic leak detection to identify a minute leak in a weld joint, that might have been missed using traditional methods. This highlights the importance of utilizing advanced technology for accurate leak detection and the importance of following stringent safety protocols throughout the testing process.

LNG systems utilize materials that can withstand the extremely low temperatures and pressures involved. Common materials include various types of stainless steel (like 304L and 316L), aluminum alloys, and nickel-based alloys, each chosen based on specific properties and their suitability for different parts of the system. For example, 9% Nickel steel is frequently used for large storage tanks due to its good toughness at low temperatures.

Understanding these materials’ properties is essential for effective inspection. This knowledge includes understanding their susceptibility to corrosion, embrittlement, and fatigue at cryogenic temperatures. I am familiar with various material standards and specifications (like ASME, ASTM, and ISO standards) that define material requirements for LNG service. I can interpret material test reports, identify potential material degradation issues, and recommend appropriate corrective actions based on material properties and inspection findings. Knowing the specific properties of the materials helps in making appropriate NDT selections; for instance, selecting the correct ultrasonic transducer and setting for a specific steel alloy.