Vibration aging is China's key "efficiency, energy saving, environmental protection" technology. It applies a dynamic stress to the workpiece in the form of vibration. When the dynamic stress is superimposed on the residual stress of the workpiece itself, it meets or exceeds the microscopic yield limit of the material. The workpiece will undergo microscopic or macroscopic local and overall elastic plastic deformation, and at the same time reduce and homogenize the residual stress inside the workpiece, and finally achieve the aging high-tech to stabilize the workpiece size and geometric precision. It is of great significance for enterprises to improve product quality, reduce time-effect costs, improve production efficiency, and solve the problem of environmental pollution caused by coal-fired heat aging. A juicy, tender steak is aperfect steak experience,but the absence of a sharp,handy knife can really spoil the wxperience.We can provide customers all over the world with the best quality and colorful Plastic+TPR handle steak knives,also we can customize different steak knives according to the living habits of different countries. Steak Knife Set,Stainless Steel Steak Tpr Handle,Tpr Handle Steak Knives,Tpr+Pp Handle Steak Knife HONG TAO KITCHEN INDUSTRY CO.,LTD , https://www.jmhtkitchenware.com
Our company began to experiment with vibration aging technology in the mid-1980s, but because the equipment is manual vibration aging equipment, the operator relies on the feeling and experience, resulting in frequent noise during vibration, resulting in the technology can not be applied properly. With the increase of production volume of our company, the traditional thermal aging process has seriously restricted the development of our company. In 2007, our company introduced a fully automatic vibration aging equipment that automatically selects the vibration aging process parameters by computer, can effectively guarantee the vibration aging quality, and is easy to operate. Through nearly three months of experimental research on the main large castings such as bed and pallets of our company, good results have been obtained, which can effectively replace the secondary thermal aging treatment of castings.
In the following, combined with the practical experience of the use of vibration aging technology in our foundry branch, we will discuss how to better apply vibration aging technology. It is hoped that the same industry will help the application of vibration aging technology.
One. Must develop the correct vibration aging process
The effect of vibration aging depends on the choice of process parameters for vibration aging (including excitation point, support point, excitation frequency, excitation force, and excitation time). The selection of these parameters should be based on the natural vibration characteristics of the workpiece. Only by exciting with the natural frequency of the workpiece can the residual stress of the workpiece be reduced most economically, simply and quickly. However, it has been found in practice that due to the irrational use of the magnitude of the exciting force, the frequency of the exciting force and the position of the exciting point, sometimes the effect of eliminating the residual stress is not achieved, and the workpiece only partially eliminates the residual stress; The aging must be performed in the following steps.
1. Support the workpiece with a rubber pad. The support position should be at the pitch of the main vibration frequency of the workpiece (the minimum amplitude at sub-resonance).
2. The exciter should be rigidly fastened at the peak of the main vibration frequency of the workpiece (the amplitude at the sub-resonance is large).
3. The vibrator should be placed away from the exciter and the amplitude is large. The maximum resonance acceleration measured here should be within the range of acceleration values ​​required by the equipment (greater than 60mm/s2).
4. Adjust the eccentric angle of the exciter to arouse different formants. The basic points are: 1. When the low frequency formant needs to be obtained, the eccentric angle should be increased; when the high frequency formant needs to be obtained, the eccentric angle should be reduced; Generally, the low-frequency formant should be selected for vibration aging treatment, so that the effect is better, and the vibration sound is small, and the influence on the device is also small. 2. When the resonance node line is not obvious, the eccentric angle should be increased; when the motor current value and the speed value are unstable, the eccentric angle should be reduced.
5. The automatic process program should be used preferentially. The computer automatically selects the best sub-resonance point for automatic aging treatment to ensure the vibration aging effect is stable and reliable. If necessary, the semi-automatic vibration aging treatment can be performed manually.
6. The vibration aging time is 15-30 minutes. For small workpieces, the lower limit is selected. For large workpieces, the upper limit is selected.
7. When sweeping, if there is no formant, the motor speed will continue to rise. When the speed rises to 6000r/min, it should be stopped manually, re-select the appropriate process parameters and sweep.
8. When using the vibration platform for aging, the workpiece must be rigidly fastened to the platform and cannot be loosened. If there is looseness during the vibration aging process, it must be re-tightened and then aging treatment to ensure stable and reliable batch aging effect.
9. The vibration aging process curve should meet the requirements of the “parameter curve detection method†of the national standard for vibration aging technology and be kept for reference.
The above picture is a concrete example of our company's secondary aging for castings. The parts are our company's bed castings. The parts are made of HT250 and weigh about 17 tons. The outer dimensions are 9800 mm × 1500 mm × 550 mm. The process parameters are as follows: 1. The position of the exciter is in the middle of the part; 2. The support position of the pad is 1700 mm from the end (four points); 3. The position of the vibration is at the end corner;
4. The eccentric angle is 15°; 5. The aging current is 3~4 amps; 6. The aging time is 2×15 minutes. The figure below shows the effect diagram after the parts are vibrated and aging.
two. Serious and responsible operator
Operators are people who use vibration aging equipment for many years, and they play a decisive role in the quality effect of vibration aging. The workpiece is subjected to vibration aging treatment, which is different from the heat treatment. The surface of the workpiece with thermal aging has an oxide layer, and the effect can be roughly judged from the appearance, but the appearance of the workpiece with vibration aging does not change, and the effect cannot be judged from the appearance. In addition, the vibration aging time is very short, that is, 15-30 minutes, can effectively eliminate residual stress in such a short time, depending on whether the operator is responsible for the vibration aging process requirements. Only the responsible operators can effectively guarantee the vibration aging process.
three. Strict quality management system
Strict quality management system is necessary for the production of any industrial enterprise, and vibration aging production is no exception. At present, a prominent problem in the application of vibration aging technology in China is that quite a number of enterprises have not established a strict quality management system for vibration aging production. As early as 1992, China promulgated and implemented the national standard for vibration aging process, which provided a scientific test basis for vibration aging inspection work. The fully automatic vibration aging equipment can record the vibration aging process curve and parameters for each vibration aging treatment. As long as the process curve is compared with the national standard, the vibration aging quality effect can be directly verified. Each time the operator processes a workpiece, the vibration aging process curve is recorded and checked by the quality inspector. After the inspection is passed, the processed workpiece is transferred to the next process.
Since July 2007, our company has officially applied vibration and aging to the second generation of bed castings of our factory. It has been four years since the vibration-aging treatments have never been deformed during the user's use. Poor quality information feedback indicates that the vibration aging process is reliable. In short, vibration aging is an environmentally friendly, energy-saving, and efficient process that can largely replace thermal aging; however, if the vibration aging process is unreasonable, the workpiece cannot be aging. As long as the automatic vibration aging equipment is used, and the correct vibration and aging process is objectively and scientifically determined for the aging workpiece, and the responsible operator and strict quality management system are required, the vibration aging technology can be applied.