This thread is for a discussion on the causes and effects of temper embrittlement. The topic comes up every now and then, and really deserves a thread to be able to point people to when needed. I will do my best to keep things as simple as possible, while at the same time covering the important parts. Besides a number of years as a practicing metallurgist in steel foundries I am also using my 3 most common reference books for this type of topic that I keep within reach on my desk: The ASM Heat Treater's Guide (2nd ed, 1995), Structure and Properties of Engineering Alloys (2nd ed, William F