OEM manufacturers require specific strength testing to assure that part performance complies with design. This valve stem was strength tested with a tensile pull, and it broke outside the friction welded joint where the shaft meets the disc. The tensile test shows that the friction welded bond is stronger than the parent material.
NOTE: This finished sample also illustrates that the friction weld zone can be machined like solid parent material.
As in the other “petal” bend tests on this page, this sample shows the friction weld bonded joint between a thin-walled tube and a solid cap is successful.
Here heat-treat hardened 8620 steel is bonded to stainless steel. The hollow stainless tube was cut for a “petal test”. The friction weld parameter is proven successful in this test example.
Another bend test, another win for friction welding.
This 1/8″ diameter steel bar is comprised of one-half Nitride hardened steel joined to another half in untreated mild steel. You can see that the friction weld is stronger than either parent material side.