some

Also a metallurgist, and hammer faces ARE hard enough to chip. As far as exploding, that is a relative term, but the hammer faces can definitely violently chip.

Also saw the MythBusters episode and that was a poor experiment and test. The heat treating process that they used near the end of the show was uncontrolled/sloppy and resulted in the wrong microstructure to cause chipping -- I didn't need to see the end to know that hammers would bend rather than chip. During the test, the heating temperature was too low (some people recommend a magnet to test for proper heat, but that is wrong as well because the nonmagnetic point for steel is about 300 degrees too cold to quench); they walked about 10 yards before they quenched the hammer so they lost even more temperature; they quenched it in oil (probably should have been in a water blast for the hammer steel chemistry); I am assuming that they believed that oil would add some carbon (another wive's tale); and finally, even if they did the heating and quenching right (which they didn't), they removed the hammer from the oil before it would have reached a low enough temperature to form martensite (harden). All in all, a failure.