Main Influencing Factors and Control of Heat Treatment Quality of Throat Hoop

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 flexural strength required by the design, avoid the phenomenon of relaxation and other 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 vital impact on the internal quality of high strength throat hoop, especially its internal quality. 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.

Heat treatment process is characterized by changing the internal structure of the material to obtain the required performance and quality of various throat hoops. The shape of the material or throat hoop is usually not changed during the process. Because the quality characteristics of products endowed by heat treatment are often not intuitive internal quality (such as tensile strength, section shrinkage, elongation etc.), in order to ensure the quality of heat treatment in production, throat hoop or sample with furnace should be tested by special instruments and equipment. However, due to the limitation of inspection sampling rate and inspection location, throat hoop of each specification or even each one should be inspected. As far as the throat hoop of the furnace is concerned, its inspection is local or individual, and it is difficult to test 100% of the heat treatment quality. Therefore, all the test results can not fully reflect the heat treatment quality of the whole batch of throat hoops or the whole throat hoops.

Once heat treatment quality problems occur in batch or continuous production of heat treatment production, the previous work is discarded, resulting in great losses. If heat treatment defects are missed, serious mechanical failures will easily occur, resulting in incalculable losses. Therefore, it is particularly important to strictly control the whole process of heat treatment production and implement comprehensive quality management for heat treatment process. It is of special significance to carry out ISO9000 series certification work in the throat hoop industry, and it has received widespread attention. Heat treatment production, like other production processes, can not be separated from the four elements (Man, Machine, Material, Method, referred to as 4M). There is no consideration of environmental protection. They are the main factors affecting the quality of heat treatment products. They interact and restrict each other, and ultimately determine the quality of heat treatment of throat hoops.

Referring to ISO9000:2000 standard requirements, this paper analyses the main points of 4M heat treatment management and puts forward corresponding control measures to ensure the heat treatment quality of throat hoops.

1. Participants (persons)

The departments involved in heat treatment production generally include equipment maintenance department, tooling management department, measurement management department, procurement and supply department, production, technology and inspection department (including metallographic examination). In order to control the quality of heat treatment products, all members of all departments must be mobilized and involved. Quality control is a process control, not just rely on a few people or departments can do a good job. In order to achieve full participation in quality control of heat treatment of throat hoop. Firstly, it is necessary to clarify the responsibilities and powers of all kinds of personnel, and stipulate that employees must bear the responsibility of solving problems when exercising their rights. Secondly, enterprises should organize job training in a planned way, improve the operation skills and quality control skills of employees, and carry out qualification certification for important positions such as high frequency induction heating. Heat treatment production 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 regularly 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 heat treatment throat hoop. In addition, enterprises should actively create conditions to encourage employees to innovate and develop, and achieve continuous improvement.

2. Equipment tooling (machine)

There are many kinds of fixtures for heat treatment production equipment, and some precise measuring instruments are often used to provide equipment, fixtures and measurement guarantee. Improving the reproducibility and reliability of heat treatment process is based on the guarantee of heat treatment quality of throat hoop, and also considers the safety of operators. Operators are required to strictly abide by the operating rules of equipment, tooling and measuring tools, and to carry out civilized operation and maintenance. Maintenance personnel of heat treatment equipment should do well in daily maintenance and regular maintenance of equipment, and timely improve maintenance of equipment, strictly implement the management system of tooling and equipment, require operators to use tooling correctly and return it in time according to the system and process requirements, and require tooling management departments to do well in the issuance, storage, maintenance and verification, adjustment, maintenance and updating of tooling. Change jobs. Strict implementation of the measurement management system requires operators to correctly use and maintain measuring instruments in accordance with the system and the quality requirements of heat treatment of throat hoops. Measurement departments are required to do a good job in calibration, maintenance and appraisal of measuring instruments according to regulations. Sometimes a little error of temperature control instruments will affect the judgement of operators.

3. Hoop material (material)

For heat treatment production of throat hoop, although the material has been determined at the time of design and its own factors can not be controlled, the factors that affect the quality of heat treatment of high strength throat hoop, such as mixing, mistake, loss, rust, bump and deformation, often appear in the treatment, transporting, counting and work of heat treatment production, can be effectively and conscientiously worked by relevant personnel to avoid mixing, leakage, mistake and other factors. The occurrence of good phenomena. The inspection department is required to do a good job in material inspection and status identification (such as using different colors of oil to paint different steel grades), and the material storage department is required to do a good job in material identification, receiving, handling and storage; the production department is conscientious and meticulous in doing a good job in product identification, storage, storage and other work, timely discovery of problems and inform the relevant departments to deal with them in a timely manner. In heat treatment production, many problems of high strength throat hoop materials can be solved by corresponding technology as long as they are found in time. For example, the quenched bolt later found that the grade 35 # steel misused ML35 steel, after lowering tempering temperature, testing tensile strength qualified "release" use; longer specification bolt deformation exceeded the standard, can be solved through the corresponding straighter process; the throat hoop surface rusted can be acid washed and blackened again, more oxide skin can be solved by sand blasting. Of course, it is necessary to solve the problem after the event, and we should act cautiously.