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| Calling News |
| Application of lead bronze |
| 2009-10-30 15:19:43 |
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(has been browse 132 times)
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Lead bronze had been widely used in machinery manufacturing industry since the beginning of 20th century, mainly in the fields of aeroengine, heavy oil engine and other axle bearing manufacture under high speed and high pressure. Its working property far exceeds that of babbit alloy and other copper alloys.
During 1950s and 1970s, our country widely used the second kind lead bronze to manufacture the tractor axle bearing of agricultural machines, especially the bearing bushing of railway engines and vans. These are mainly double alloy.
After 1980s when our country brought forward the reform and open policy, our machinery manufacturing industry learned from America, Germany, France and other advanced countries, and imported new technology in machinery manufacture in many industries. Besides, mines and enterprises purchased a lot of effective and advanced equipments with long life abroad, such as various models of gyratory breaker, rotary crusher, excavator and digging machine for the use in mines, waterpower equipments, thermal power generation equipments, various large water pumps, etc., all of which adopt the first kind lead bronze axle bearing weighing from 10kg to 1310kg (max diameter Φ1450mm, and max height 1390mm), with the characteristics of high pressure tolerance, high speed tolerance, shockproof, antifatigue, small frictional coefficient, no crack, no galling, protecting related axis and long life.
The lead bronze centrifugal casting technics was not qualitifed according to the advanced foreign drawing sheet, so the machinery manufacturing industry of our country had to make orders in foreign countries. Some enterprises adopted copper alloy instead of lead bronze because of the high price, which led to the short life and great disturbance. Besides, foreign manufacturers even didn't provide the drawing sheet of wearing parts, leaving along the materials and technics, so when the operational life span of imported equipments ended, mines and enterprises couldn't manufacture these parts even though they know what the material was. So they had to purchase the parts from the manufacturer, where the price was higher than 300 RMB yuan per kilo, and they had no other choices.
It is hard to guarantee the lead bronze parts even though they are sand shell moulding. The minimum granule of parts manufactured in this way is 24‰mm, which distrubute asymmetrically. The lead granule of imported centrifugal casting parts is only 2‰mm and distrubute symmetrically. There are hundreds of lead granules in each square millimetre, and the contexture of centrifugal casting parts is fine, so the life is long.
Since the establishment of our factory, all the members of our factory, from Board Chairman to technicians, knew that high-lead bronze castings still remain a blank in the centrifucal casting field of our country. So our Board Chairman brought forward the idea that we could do that foreigners do, we should be determined to win honor for our country and we must succeed even though investing a million RMB yuan in it.
With the leadership and support of our Board Chairman and the encouragement of "United, advancing, struggling, developing, honest, striving for the best", our technicians began the experiments and research in May 1998. We began from small parts and then came to bigger parts. We experienced numerous failures, and we analyzed, studied and kept improving after each failure. In this way, we went on the research on the technics. “Where there is a will, there is a way", after expriments on small parts, medium parts and large parts, we finally discovered the rules of high-lead bronze centrifugal casting and measures that must be taken.
By the end of 20th century, we had been able to manufacture not only small parts weighing a few kilos, but also big parts weighing several tons, which not only filled in the blank of high-lead bronze centrifugal casting technics of copper alloy casting of our country, but also added a brilliant point for our country's casting industry.
Since 2001, we began to step out of the factory and propogandize our products by distributing advertisements and attending exhibitions. Finally the lifetime of our high-lead bronze parts is 1～2 times longer than that of other enterprises, which has reached international advanced standard and gained us social profit.
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