Gallery of Dramas. Broken Enfield Parts!

[breakeyp]

I had the unplesant opportunity to investigate and resolve? heat treat issues in the automotive business. Given the volume of fasterners Ford uses every day, it is not surprising that problems happen. Chassis Division had 7 metallurgists/material engineers alone.

Problems can be due to:
1. Improper heat treat
2. Incorrect materials or materials out of spec
3. Batch heat treat may mean parts on the out side of the heat source don't see proper temperatures or parts too close to heat may be over heated. A hardened part may not be drawn down to the final temperature. I have seen a hardend part drop on the floor and break.
4. Slag/impurities imbedded in part leads to weak cross section
5. During the milling process at the steel mill--one billet is mechanically welded to the next and the seam becomes a srtess point subject to failure in a later manufactured part.
6. Part notched or dented during manufacturing process prior to heat treat.

A coarse cross section at a break indicates an immediate failure. If the break surface is smooth with a series of curved swirls--the failure was ductile and happened over time.

I have a three inch thick textbook from a class on the Theory of Failures that attempts to cover the subject. If someone is really desperate for reading material, I can furnish the title and particulars.