Heat treatment can make the high-strength throat hoop obtain the comprehensive mechanical properties such as certain strength, good plasticity, toughness, low notch sensitivity and high bending strength required by the design, avoid relaxation phenomenon and use performance, so as to ensure the quality and reliability of the throat hoop and improve the market competitiveness of the throat hoop products.
Heat treatment process has a crucial influence on the internal quality of high-strength throat hoop. Therefore, in order to produce high-quality high-strength throat hoop, it is necessary to have advanced heat treatment process and heat treatment process control.
The characteristic of heat treatment process is to change the internal structure of the material so that all kinds of throat hoops can obtain the required performance and quality. In the process of heat treatment, the shape of the material or throat hoop is usually not changed. Due to the quality characteristics of the products given by heat treatment are often non intuitive internal quality (such as material tensile strength, reduction of area, elongation, etc.), in order to ensure the quality of heat treatment in production, it is generally necessary to test the throat hoop or furnace samples through special instruments and equipment. However, due to the limitations of inspection sampling rate and inspection parts, for each specification of throat hoop or even each specification of throat hoop For the throat hoop of furnace, its inspection is local or individual, so it is difficult to achieve 100% inspection of heat treatment quality. Therefore, all the test results can not fully reflect the heat treatment quality of the whole batch or the whole throat hoop.
As the heat treatment production is put into batch production or continuous production according to furnace number, once the quality problem of heat treatment occurs, all the previous efforts are wasted, resulting in great losses. It is easy to have serious mechanical failure and cause incalculable loss in case of missing inspection of heat treatment defects. Therefore, it is very important to strictly control the whole process of heat treatment production and implement comprehensive quality management. It is of special significance to carry out ISO9000 series certification work in throat hoop industry, and it has been paid more and more attention. Like other production processes, heat treatment production can not be separated from four elements (man, machine, material, method, 4m for short). Here, environmental protection is not considered temporarily. They are the main factors that affect the quality of heat treatment products. They affect each other and restrict each other. Finally, the quality of heat treatment of throat hoop is determined.
Referring to the requirements of ISO9000:2000, the key points of 4m heat treatment management are analyzed and corresponding control measures are proposed to ensure the quality of heat treatment of throat hoop.
- Participants (person)
The departments involved in heat treatment production generally include equipment maintenance department, tooling management department, measurement management department, procurement and supply department, production, technology, inspection department (including metallographic inspection), etc. In order to control the quality of heat treatment products, all members of all departments must be mobilized to participate. Quality control is process control, not only depending on a few people or departments can do it well. In order to realize the whole staff participating in the quality control of heat treatment of throat hoop. First of all, it is necessary to clarify the responsibilities and authorities of all kinds of personnel, and at the same time stipulate that employees must bear the responsibility of solving problems when exercising their rights. Secondly, enterprises should organize post training in a planned way, improve the operation skills and quality control skills of employees, and conduct qualification certification for important posts (such as high-frequency induction heating). The production of heat treatment is very professional. Only when employees have enough knowledge, skills and experience, can they be competent and fully participate in the work. Secondly, we should often carry out various forms of quality awareness, communication awareness, professional ethics and professionalism education, improve the quality of employees, promote mutual teaching and learning, and jointly improve the quality of throat hoop heat treatment. In addition, enterprises should actively create conditions to encourage employees' innovation and development and achieve continuous improvement.
2. Equipment tooling (machine)
There are many kinds of tools for heat treatment production equipment, and some precise measuring instruments should be often used to provide equipment, tools and measurement guarantee. To improve the reproducibility and reliability of heat treatment process is based on the guarantee of heat treatment quality of throat hoop and the consideration of safety of operators. Operators are required to strictly abide by the operating procedures of equipment, tooling and measuring tools, and implement civilized operation and maintenance. The maintenance personnel of heat treatment equipment shall do a good job in the daily maintenance and regular maintenance of the equipment, timely carry out the improvement maintenance of the equipment, strictly implement the management system of tooling position apparatus, require the operator to use the tooling correctly and return it in time according to the system and process requirements, and require the tooling management department to do a good job in the distribution, storage, maintenance and verification, adjustment, maintenance and change of tooling Change jobs. Strictly implement the measurement management system, require the operator to correctly use and maintain the measuring instruments according to the system and the quality requirements of throat heat treatment, and require the measurement department to calibrate, repair and identify the measuring instruments according to the regulations. Because sometimes a little error of the temperature control instrument will affect the judgment of the operator
3. Throat hoop material (material)
For the heat treatment production of throat hoop, although the material has been determined at the time of design and its own factors cannot be controlled, the factors affecting the quality of heat treatment of high-strength throat hoop, such as mixture, wrong material, loss, rust, bump and deformation, often appear in the treatment, transportation, inventory and work of heat treatment production, which can be seriously and effectively worked by relevant personnel, Avoid mixing, missing and wrong materials. The inspection department is required to do a good job in material inspection, status identification (e.g. paint different colors with different steel grades), material storage department is required to do a good job in material identification, receiving, handling and storage; production department is required to work carefully, do a good job in identification, storage and storage of products in process, timely find out problems and inform relevant departments to deal with them in a timely manner. In the production of heat treatment, many problems of high-strength throat hoop materials can be solved by corresponding technology if they are found in time. For example, ML35 steel was found to be misused for the quenched bolt, and the tensile strength was tested to be qualified after the tempering temperature was reduced. If the deformation of the bolt with longer specification exceeds the standard, it can be solved by the corresponding straightening process. If the surface of the throat hoop is rusted, it can be blackened again after pickling, and if there is more oxide skin, it can be solved by sand spraying. Of course, "after the fact" is the only way to solve the problem. We should be careful.
4. Process specification (method)
Heat treatment is an important process in the processing of high-strength throat hoop, which plays a key role in improving the market competitiveness of throat hoop products. Heat treatment is essentially a process to improve the performance, service performance and service life of materials by strictly controlling the heating and cooling process.
The theory and practice of heat treatment production technology are very strong. A set of suitable heat treatment process and relatively perfect operation specifications are necessary to control the quality of heat treatment. From the perspective of quality control, the formulation of heat treatment process should be based on the specific high-strength throat hoop materials, relevant equipment, tooling and staff's operation skills to select appropriate process parameters. The heat treatment technologist must be familiar with the production site, and constantly improve the process and continuous improvement through the confirmation of practice
