【Weekly Topic】What are the differences between metal surveillance and boiler inspection? (8.015-8.21)

Metal supervision in power plants refers to the technical management activity of monitoring and inspecting the metal components under high temperatures and high stresses during the operation of thermal power plants, in order to ensure their safe use. Boilers are generally subject to unified and standardized inspections by specialized boiler inspection departments; these inspections involve cold-state testing of the boilers. Through ultrasonic testing, dye penetrant testing, hardness testing, metallographic sampling, and wall thickness measurement of various metal materials and welds in the boiler, a comprehensive analysis is carried out to determine whether the boiler can still operate within its designed parameters. Boiler inspection refers to the regular examination of the boiler itself, its associated pipelines, and auxiliary equipment during normal operation, with the recording and reporting of any defects found, as well as carrying out simple maintenance tasks. That is, what is commonly referred to as inspection, discovery, analysis, coordination, handling, summarization, and improvement.

This post was last edited and replied to by dongjiang1001 on 2011-8-18 at 19:34. Reply 1# zgj2405 Metal monitoring – Overview: With the rapid development of the power industry, there are an increasing number of large-capacity, high-parameter generator sets in thermal power plants, which places greater and greater demands on metal monitoring activities. The metal components within the supervision scope of the operating units in thermal power plants, such as main steam pipes, reheat steam pipes, pressure vessels, important rotating components, fasteners, and boiler heating tubes, operate for extended periods under conditions of high temperature, high pressure, and corrosive media. As a result, changes occur in the structure and properties of these metal materials, and it is even possible for certain metal components to fail. Once such components fail, accidents can occur, sometimes even serious ones, which directly affect the safe and economic operation of the power plant. In recent years, accidents involving metal equipment in high-temperature and high-pressure power plants have occurred frequently: cracks at the root of 600MW turbine blades, as well as broken blade springs ； The high-pressure cylinder bolts of a 300MW unit fractured within less than a year of operation ； After long-term operation, numerous crack-like defects were found at the root of the welds connecting the main steam pipes and the reheat steam in 125MW units. Explosions and leaks in the tubes of a boiler’s heating surfaces are particularly common, accounting for 88% to 90% of accidents involving metal equipment. To prevent such accidents and take appropriate preventive measures, it is necessary to understand and grasp the main changes that occur in high-temperature metal components over time as well as the patterns behind these changes; moreover, it is essential to strengthen oversight of metal-related technologies. Metallic technology supervision is a key measure to ensure the safety of power equipment and to provide power supply in an economical and stable manner. All units involved in power generation, power supply, as well as power construction and maintenance must strictly comply with the Ministry’s DL438‑91 \"Regulations on Metal Technology Supervision in Thermal Power Plants\" and the regulations issued by the power grid authorities regarding metal technology supervision, in order to ensure proper implementation of such supervision tasks. Metallic equipment supervision should adhere to the principle of safety first and prevention foremost, combining professional supervision with public oversight to continuously identify defects and potential hazards in equipment, take preventive measures, and improve the overall condition of the equipment. Metallic technology supervision involves providing comprehensive technical oversight throughout the entire life cycle of equipment – from selection and design to manufacturing, installation, commissioning, trial production, operation, decommissioning, maintenance, and technical upgrades. It entails identifying problems in a timely manner and taking effective supervisory measures to reduce and prevent failures and damages to metallic equipment at each of these stages. The purpose of metal technology supervision is to prevent various accidents caused by issues with metal materials and welding quality at all stages of the comprehensive management of metal-based equipment and components, to extend the service life of such equipment, and to ensure the safe and reliable operation of the systems. Metal supervision – Metal technology supervision and management model at the grassroots level. Supervision work at the plant (company) level is carried out under the leadership of the plant manager (director), with the chief engineer being responsible for it in practice. A dedicated metal supervision officer shall be appointed in the production management department to be responsible for the centralized management of metal supervision tasks within the organization. Under the leadership of the chief engineers of each factory (company), relevant superior regulations, standards, rules, and instructions are carefully implemented ； Establish and improve the metal technology supervision network, holding at least two meetings of this supervision network each year ； Complete on time the monthly reports on metal monitoring activities, the reports on equipment abnormalities, as well as the quarterly and annual summaries. Develop detailed implementation rules or regulations for metal monitoring work in the organization, taking into account the specific conditions of the equipment ； Ensure comprehensive management of metal surveillance throughout the infrastructure construction phase of new units in the organization ； Participate in the investigation and analysis of major equipment accidents, and formulate countermeasures against such accidents ； In coordination with relevant departments, machine and boiler maintenance, metal monitoring during operation, and testing tasks are carried out, along with proper metal inspection and supervision as well as general testing and evaluation ； Ensure proper supervision and management of metal materials, spare parts, and welding quality ； Establish and improve the basic work related to metal supervision records, documents, ledgers, and archives in the organization ； Carry out technological innovation, learn and promote new technologies, and continuously improve the level of testing technology. The metal technology supervision network organization is composed of departments such as boiler maintenance, operation, steam turbines, chemistry, metal testing, material supply, welding, and steel warehouses, which are responsible for carrying out daily supervision tasks within their respective areas. Given the wide scope of metal supervision, the large number of inspection items, and the heavy workload involved, it is not sufficient to rely solely on professional supervisors. Practice in accident investigations shows that many incidents involving damage to metal components in power plants are related to the rationality of the equipment design, the material selection used for the equipment and the metallurgical properties of those materials, the quality of manufacturing and installation, the level of operation, the work carried out during maintenance and renovation, as well as the quality of work performed by relevant professionals. All these factors can affect the safety and durability of metal components. Therefore, to ensure the safe use of metal components within the scope of metal supervision and thus guarantee the safe operation of the unit, it is by no means a matter solely related to the metal field; rather, it requires cooperation with technical expertise from related fields such as boilers, steam turbines, chemistry, material supply, welding, and metal testing, in order to carry out this task successfully. Therefore, the role of the supervision network is extremely important. In the metal surveillance network, the main tasks of the boiler department are to strengthen the inspection of monitored equipment and components, as well as to carry out inspections and patrols in order to prevent overheating and overpressure ； The turbine department should ensure proper supervision of rotating components ； The chemistry department is responsible for ensuring the quality of soda water and preventing corrosion and scaling ； The material supply department is responsible for ensuring the quality inspection, storage, and distribution of steel, steel pipes, as well as various spare parts, in order to prevent any errors in receipt or delivery ； The welding department must ensure high standards of welding quality and proper heat treatment, while the metal testing laboratory is responsible for carrying out metal tests and inspections. It is precisely by relying on the various specialties within the network to carry out their respective duties in daily work, to exchange information during network-related activities, to cooperate with one another, and to jointly analyze, study, and resolve any issues that arise, that metal monitoring tasks can be effectively carried out, thereby ensuring the safe and stable operation of the units. 1. Definition of equipment inspection 　　To maintain the original performance of production equipment, it is a preventive and thorough inspection process in which specified parts of the equipment are checked for any abnormalities on a predetermined schedule and using methods that involve human senses (sight, hearing, smell, taste, touch) or various tools and instruments. This approach enables potential problems and defects in the equipment to be detected early, prevented early, and addressed early; such equipment inspection is known as equipment inspection. Job Responsibilities 2. What are the “five fixed elements” of equipment inspection work? 　　1) Determining the location – Identifying the areas, items, and contents to be inspected. 2) Determining the method – Establishing the procedures for inspection. 3) Setting standards – Defining the criteria for inspection. 4) Setting a schedule – Determining the frequency of inspections. 5) Assigning responsibilities – Deciding who will carry out the inspection tasks; classification and division of labor. 3. Classification and division of labor for inspections: 1) By inspection frequency: a) Routine inspections – Performed by operators or maintenance staff on the job. b) Inspections at short intervals – Carried out by dedicated inspectors. c) Inspections at long intervals – Proposed by dedicated inspectors and entrusted to the maintenance department for execution. d) Precision inspections – Proposed by dedicated inspectors and entrusted to the technical or maintenance department for execution. e) Special inspections – Conducted when there are suspicions regarding the equipment, involving detailed inspections or precision checks. 2) By division of labor: a) Operational inspections – Performed by operators. b) Specialized inspections – Carried out by specialized inspection personnel. 3) By inspection method: a) Equipment inspections – Performed using the five senses (sight, hearing, smell, taste, touch). b) Minor repairs – Involving the repair or replacement of small parts. c) Tightening and adjustment – Involving springs, belts, bolts, etc. 3. What are the main tasks and responsibilities of dedicated inspectors? 　　1) Prepare and revise the inspection standards and plans for the equipment under management. 2) Assist in modifying the operating procedures for the equipment under management, and develop revised maintenance and repair procedures. 3) Monitor and guide daily inspection tasks, as well as conduct specialized inspections on equipment that requires it. 4) Prepare various plans such as equipment repair plans, spare parts plans, and material plans. 5) Participate in the management of equipment accidents. 6) Be responsible for the management of repair projects. 7) Maintain technical records for the equipment. 8) Submit reports related to equipment management. The four stages of management: 4. What are the four stages of inspection management? 　　1) Specify inspection standards and plans. 2) Carry out inspections and repair work in accordance with the plans and standards. 3) Check the results of these inspections and conduct performance analysis. 4) Based on the performance analysis, formulate measures for autonomous improvement. Definition of degradation tendency management: 5. Definition of degradation tendency management. In order to understand the degree of degradation of the equipment in question as well as the trends in the amount of wear and damage, it is necessary to monitor its fault parameters, conduct regular tests to measure the degree of degradation, manage the quantitative data related to equipment degradation, and analyze the causes and locations of degradation. This allows for the control of the degradation tendency of the equipment, thereby predicting its service life and enabling maintenance to be carried out in the most economical manner. Equipment Inspection Sheet: The equipment inspection sheet is a document that allows operators to carry out preliminary checks on the equipment they use during each shift; it records the actual condition of the equipment. It serves as an important basis for guiding repairs to the equipment, and it is a key step in shifting from reactive repair to proactive prevention. 　　Production steps: 1. Raise the question (define) ； 2. Preliminary cause analysis ； 3. Process decomposition (common methods include brainstorming, 5 Whys, Y=fX, and matrix tables) ； 4. Improvement methods ； 5. Implement and summarize ； 6. Promotion and control.