By -
Date 10-09-2001 20:30
Without actually seeing the component, it is difficult to give a definitive answer. General guidelines that could answer some of your questions are as follows:
1) Strength of the construction can be the same, because you only put the material where you need it in a welded fabrication.
2) Stiffness can also be the same, for the same reason given above.
3) Generally vibrations will be lower in a casting, because it has more material around to act as a "damper".
4) If you have a sound casting, then the casting's fatigue properties should be better because a weldment has NO fatigue limit. The fatigue properties can be improved by the position of the welds and their final shape and finish, but the weldment will still have a finite fatigue life. On the other hand, if you have a dirty casting (often a problem) the fatigue properties will not be so great either.
The bottom line of the performance of a welded fabrication or casting will rely greatly on:
1) The design.
2) Workmanship during manufacture of the component.
A good design and workmanship in either method of manufacture will render a good component that meets the design criteria. To decide on the final method of manufacture will mostly dependent on economics.
Regards
Niekie Jooste