When producing and processing the parts like the upper and lower pedestal rings of a product, we always face the technical problem of macro deformation due to processing stress, resulting in low percent of pass, long production cycle and high cost. To pass the narrow bottle neck and ensure the smooth mass production of the key projects, our company resorts to solve such technical difficulty through vibratory stress relief by way of technical discussion, experiment and market investigation and research.
Vibratory stress relief, the so called ¡°Vibratory stress relief¡± method abroad, is a technical way to homogenize and relieve the residual stress within metal framework through resonant vibration, and is an attractive alternation of thermal stress relief.
In 2005, our company has introduced ¡°Navigator Expert System for vibratory stress relief¡± from Beijing Semboo Science and TechnologyCO,.LTD. The equipment, through installment, test, sample experimental manufacturing and processing, was finally applied in the mass production of the key projects and the production of liquid pressure bracket, entry-driving machine and so on, proved to be very effective.
- Problems exist in the original technics.
Our company manufactures large amount of castings, forgings, welding and large machine work pieces, which would have residual stress within due to cold and hot machining during casting, forging , machine work and using process, causing imbalance of the stress within the work pieces. This will lead to quality problems as obvious deformation and cracking under the affect of stress. In order to solve these problems, reduce and homogenize the forming inner stress and ensure precise measurement of the work piece, our company used to apply the following two methods in the production: first was the thermal stress relief, and second was natural stress relief, both of which had many disadvantages. Thermal processing needs thermal furnaces at a higher cost, and will cause pollution to the environment. it¡¯s hard to control the technics, which easily makes the work piece fragile; while the production cycle of natural stress relief is too long to be used in the production of small quantity and multi-variety.
- Introduction to the new tech equipment
Our company introduced from Beijing Semboo Science and TechnologyCO,.LTD the ¡°Navigator Expert System for Vibratory Stress Relief¡±, which is national key creative product. This product integrates many high and new-tech such as computer technology, communication and signal processing technology, automatic control technology and so on, adopting the advanced stress relief method of frequency spectrum and harmonic wave to make the processing effect perfect.
The relaxation rigidness of work pieces, after processed through this equipment, is obvious better than through thermal stress relief, and largely decreases the deformation under dynamic and static loading.
This equipment enjoys many advantages as high efficiently energy saving without pollution by three wastes and no restriction to field.
- Application of the new tech equipment
In the second half of 2005, the Vibratory stress relief equipment brought by our company stated to be used in the military and civil material production, and has seen a wide application in the stress relief of forging, welding, machine work metal pieces.
- For one product made by our company, the upper and lower pedestal rings of which use aluminum alloy forging roughcasting, as it is , the size of the roughcasting is rather big, so the finished product after processing weighs only 1/3 to 1/5 of the roughcasting. The parts have simple design and structure, big diameter¦µ1970-¦µ1782, small cross-sectional area, complicated shape and poor overall rigidness, which will be likely to cause deformation due to machinery cutting stress under the influence of tension, cutting force and heat. When making sample of the upper pedestal ring rollaway nest¦µ1884H11¡¢[¦¯ 0.3] and lower rollaway nest¦µ1936H11¡¢¡¾¦¯ 0.5¡¿, the stress was relieved through TSR, which cost more time and hampered the process of mass production, resulting in a big problem to the quality and progress of mass production. This problem became a headache for the company as no solution was resorted after efforts made from various sides.
- Our company has a history of more than 20 years in producing liquid pressure brackets, enjoying an absolute fame on the market. With the increasing demand of the market, we are required to shorten production cycle, and reduce production cost on the base of good quality. The product has many welding components such as top beams, bases and link rods . Welding will lead to great residual stress and cracking. Bracket ZF3000£¨158 sets£©¡¢ZF3200£¨104 sets£©¡¢ZF7200£¨120 sets£©¡¢ZFSB4200£¨100 sets£©£¬ZFS2600£¨83 sets£© that were produced in 2005 all adopted the Vibratory stress relief tech in replace of the TSR tech to relieve welding stress, ensure precision of the dimension and reduce welding cracking. The Vibratory stress relief tech relieves the stress at peak value, and can compete with or even overshadow TSR. At the same time, production cycle is greatly shortened, together with a rather lower cost and cost saving of TSR up to 350,000 RMB.
- Type EBZ-90¡¢EBH132 entry-driving machines are the main line product of our company, which are produced every year in large quantity. To increase efficiency and save cost, we decided to change the TSR tech to Vibratory stress relief to relieve the stress within the structures in 2004. When actually put into use, the Vibratory stress relief equipment has effectively relieved the stress in the structure pieces as it does in the liquid pressure bracket, and put welding deformation under control successfully. Especially those key pieces with complicated structure and high requirement to the precise size, such as the rear casing , after processed through vibratory stress relief, reduce the welding deformation greatly thus meet the requirement of drawing design and increase the production quality and efficiency to a large extent.
- In 2006, our company used Vibratory stress relief tech in the production of various types of road rollers, mainly in processing the steel wheel, successfully solving the problem of deformation due to stress within the work pieces, and basically ensuring that the stress deformation of big loop-forming pieces is under control.
Through one-year technical exploration, the Vibratory stress relief equipment of Beijing Semboo Science and Technology Co,.LTD is applied in our production of military and civil material. Its obvious effect advantage has enabled it to replace many TSR and NSR tech in the manufacturing of the metal components. This tech has not only improved product quality, shortened production cycle, increased production efficiency and reduced the production cost, but also has made great contribution to the mass production of the key projects. Since the technics was applied in 2005, TSR cost has been saved totally to 500,000RMB, achieving great economic benefit.
Baotou Northern Heavy Industry Group Corporation
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