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The Disparity of Tungsten Carbide Cold Forging Dies in home and abroad (1) |
| Author : Date : 2011-11-21 19:44:46 |
The Disparity of Tungsten Carbide Cold Forging Dies in Home and Abroad (1)
The tungsten carbide cold forging dies’ service life is several or dozens times than the carton steel and high carbon steel ones in producing screw fasteners. Thus ,the tungsten carbide cold forging dies have been used more and more widely in manufacturing of the screws with size below M5.Howver there is very apparent disparity existed by comparing with abroad ones. For instance ,the tungsten carbide dies for semi-round screws and countersunk cross-recessed head screws made in Japan, which is capable to forge 7 to 9 million pieces, but if it is made in home ,it is only available to produce 2~3 million pieces ,meanwhile ,its quality is not stable .Consequently ,after tested respectively ,the difference as following.
1) Structure and size
Why our dies’s service life is short,it is not because of the sizes mainly ,actually the dies sleeve and core are cylinder shape,the bottom of them are plane,thus it is very easy to machine with so simple structure .However ,when take cold-inlaying process ,the inner hole wall would be damages due to without steering angle ,even would cause some small cracks and make the inlaying quality unstable
On the contrary, the tungsten carbide dies made in Japan with the dual taper and double convex connecting structure in the connecting parts between the sleeve inner hole and die core, it is difficulty to machine since the complex structure however its inlaying quality could be kept definitely with the steering angle. Taking double-convex structure in the bottom of the dies core and its sleeve inner hole ,so as to convenient the center parts squeezed closely together which bear most of the force in processing, meanwhile ,the space left around is available to store the extra metals extruded from the hole wall. |
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