Sichuan vibration aging instrument, vibration eliminates welding stress

Vibration aging equipment manufacturer

Research on the Application of Vibration Aging Technology in Welded Structures

Welded structures are widely used in modern industry, but the residual stresses generated during the welding process seriously affect the performance and service life of the structure. Vibration aging technology, as an effective stress relief method, has demonstrated unique advantages in welding structure treatment. This article will focus on exploring the application characteristics and technical points of vibration aging in welded structures.

During the welding process, significant residual stresses are generated in and around the weld due to uneven local heating and cooling. The presence of these residual stresses may lead to deformation, cracking, and other issues in the welded structure, reducing its load-bearing capacity and fatigue life. Vibration aging can effectively release welding residual stress and improve the dimensional stability and mechanical properties of the structure by applying vibration to the welded structure.

In the vibration aging treatment of welded structures, several key issues need to be noted. The first step is to choose the timing of processing, usually after welding is completed and cooled to room temperature. For large and complex structures, segmented welding and segmented aging methods can be used. Next is the arrangement of excitation points and support points, which need to be selected reasonably according to the shape of the structure and the distribution of welds to ensure that the vibration energy can be effectively transmitted to the weld area. For long weld structures, mobile excitation can be used to ensure that each part can receive sufficient vibration treatment.

The application effect of vibration aging in welded structures has been widely verified. Practice has shown that welding structures treated with vibration aging can reduce residual stress30-60%Reduced deformation of the structure50%Above, fatigue life can be improved2-3Twice. Especially in the fields of bridge steel structures, pressure vessels, shipbuilding, etc., the application of vibration aging technology not only improves product quality, but also significantly reduces production costs and cycles.

With the continuous development of welding technology and the increasing demand for welding quality, the application prospects of vibration aging technology in welded structures will be even broader.

1、 Why is vibration aging used to eliminate residual stress in metal components

Vibration aging is gradually replacing traditional natural aging and thermal aging in practice due to its advantages such as good aging effect, strong dimensional stability of workpieces, economic practicality, low investment, and significant energy saving. During the manufacturing processes such as casting, welding, forging, and mechanical processing of workpieces, residual stresses are generated inside the workpiece. The existence of residual stress will inevitably lead to deformation and cracking of the workpiece, seriously affecting the dimensional stability of the workpiece and reducing its fatigue life. The influence of time-dependent vibration machine on metal components:

1. The impact on the mechanical properties of metal materials. After vibration aging, the yield and tensile strength of the material increase; Improved fracture toughness to prevent brittle fracture of workpieces.

2. The vibration aging instrument can reduce and homogenize residual stresses in the construction process. The workpiece is subjected to periodic additional dynamic stresses, which cause local plastic deformation at stress concentration points, and then result in significant plastic deformation overall.

3. Not only does it make the dimensional accuracy of the workpiece change less during long-term use, but it can also stabilize the part size in a shorter period of time.

4. The vibration aging device can not only reduce and homogenize residual stresses, but also improve the deformation resistance of materials.

2、 Scientific basis for eliminating welding residual stress using vibration aging processing machine

The vibration aging machine is an aging device that causes resonance in the processed workpiece. By resonance, a certain amount of vibration energy is transmitted to all parts of the workpiece, causing microscopic plastic deformation inside the workpiece. The distorted lattice gradually returns to equilibrium, thereby eliminating and homogenizing residual stresses inside the workpiece,The ultimate goal is to prevent deformation and cracking of the workpiece during processing and use, ensuring the stability of the dimensional accuracy of the workpiece.

3、 What function of vibration aging equipment should be used to remove residual stress inside components

The vibration aging machine has a significant effect on eliminating welding and casting stresses, and has been developed and applied for decades both domestically and internationally. In the manufacturing processes of casting, welding, forging, and mechanical processing of workpieces, residual stresses are generated inside the workpiece. The existence of residual stress will inevitably lead to deformation and cracking of the workpiece, seriously affecting the dimensional stability of the workpiece and reducing its fatigue life. Characteristics of welding stress relief equipment:

1. Stress relief equipment is a new product developed and improved on the basis of traditional LCD series.

2. The spectrum analysis technology with good vibration stress relief can automatically develop the vibration aging process plan and achieve human-machine dialogue.

3. All imported components are used to improve the service life and stability of the equipment.

4. The dynamic display of on-site aging process of vibration stress relief equipment ensures good aging effect and eliminates human factors.

5. Based on good spectral analysis techniques, select the excitation frequency according to optimized processes for aging treatment.

6. The time sensitive processing machine adopts pulse width modulation technology and has * anti-interference ability.

7. Designed with a 20 fold circuit safety factor, the host eliminates heat generation, resulting in a longer lifespan and 24-hour uninterrupted operation of the equipment;

8. Dual core central processing unit, with a running speed three times faster than ordinary vibration aging devices.

9. Automatically determine the success or failure of the timeliness effect according to the JB/T5926-20051 national standard. Exclude human factors.

10. The aging process, vibration amplitude and frequency band analysis adopt fine search, and the accuracy of peak and resonance points reaches one ten thousandth.

11. The internal electronic components of the vibration aging instrument are all configured according to military standards, and can work normally for a long time in complex environments such as high temperature, extremely low temperature, or severe dust.

12. The exciter is designed with dual eccentricity, dual drive, and dual circuit, greatly improving the excitation force while enhancing stability accuracy and extending service life.

13. The control system of the vibration aging instrument adopts an industrial control computer chassis, which has strong anti electromagnetic interference ability, ensuring the normal and reliable operation of the system in more harsh industrial sites.

14. High speed warning and protection function for equipment failure. If there is a runaway, high current, or high peak value, the equipment can be protected in a very short time (microsecond level, traditional equipment is millisecond level) to prevent damage to internal components and exciters, and the cause of the fault and its handling methods should be provided.

4、 How to choose the resonance exciter motor for vibration aging machine

Vibration aging equipment eliminates or homogenizes residual internal stresses through the principle of resonance, mainly by transferring resonance energy to various parts of the workpiece, causing microscopic plastic deformation inside the workpiece, thereby eliminating or homogenizing residual internal stresses inside the workpiece and ensuring the stability of the workpiece size. Currently widely used in production processes such as welding, casting, forging, and machining. Stress relief machines are gradually replacing traditional natural and thermal aging methods in practical applications due to their good aging effect, strong dimensional stability of workpieces, economic practicality, low investment, and significant energy savings. In the selection of time processing equipment, the first thing to consider is whether the exciter meets the requirements, as follows:

1. The excitation force should be large and adjustable. The excitation force of equipment produced domestically and internationally is usually around 2 tons, with the maximum being 3.5 tons, all of which are adjusted in stages after shutdown. The domestically developed continuously adjustable excitation force vibration aging system can continuously adjust the excitation force during operation.

2. During the vibration treatment process, it is necessary to have sufficient frequency stability accuracy and complete frequency fine-tuning to ensure that the components can be stably subjected to vibration treatment in resonance state. Especially for some castings, the natural frequency changes very little after vibration treatment. (For example, in C620, the frequency of the 2-meter bed casting should be reduced by less than 1Hz after vibration treatment, and a more accurate amplitude frequency characteristic curve should also be drawn for detection.). For components with low damping and narrow resonance frequency band, as long as a small frequency stability accuracy is ensured, they can be disposed of in resonance state.

3. The requirement is small in size, simple, and compatible with the system. The system has good supporting functions, including a control system, exciters, fixtures and vibration dampers, printers, etc., making it very convenient for on-site use.

4. The exciter should have a wide frequency range, which can cause more workpieces to resonate at their natural frequencies. And the frequency of the exciter needs to be continuously adjustable, so that the amplitude frequency characteristic curve can be made during vibration treatment.

The vibration stress relief machine originates from impact aging and consists of a complete set of main control box, exciter, sensor, elastic rubber pad, printing system, auxiliary card mounting tools, and related connecting wires. Processing efficiency usually only requires15-45 minutes, regardless of location, not limited by workpiece size, shape, weight, etc., can handle workpieces ranging from several kilograms to several hundred tons. The workpiece can be processed on-site without transportation and can be inserted between any processes for processing. The use of vibration aging can improve work efficiency by dozens of times, and it has the advantages of reducing environmental pollution, shortening production cycles, improving working conditions, and simplifying processes. Principle of vibration aging process:

5、 How to evaluate the aging effect of vibration aging process

The vibration aging process is a special force applied to the workpiece through vibration, called dynamic stress. When the dynamic stress is superimposed with the residual stress of the workpiece itself, it is extremely*Substances will undergo different deformations to meet people's needs. The application of vibration aging in the field of mechanical processing. Thermal aging involves heating, insulation, and cooling the workpiece to eliminate internal stress, and has specific processing and manufacturing methods.

according toAccording to the JB/T5926-2005 standard of the Machinery Industry Department, under the same pre vibration preparation conditions and sweep rate, if any of the following situations occur, it can be determined that the vibration aging process effect has been achieved in some areas of the workpiece in the current state:

1. The acceleration time (A-t) curve rises and then flattens

2. The peak value of the acceleration frequency (A-N) curve increases after vibration compared to before vibration

3. Fission phenomenon occurs in the acceleration frequency (A-N) curve after vibration

4. The acceleration frequency (A-N) curve shows a decrease in frequency after vibration compared to before vibration

5. The acceleration time (A-t) curve rises, then falls, and finally flattens

6. The bandwidth of the acceleration frequency (A-N) curve narrows after vibration compared to before vibration