Metallurgy Principles, Steel and Knife Properties, Toughness

How Does Grain Refinement Lead to Improved Properties?

Larrin

Update 6/21/2018: A new journal article has been released on the effect of grain size which is very interesting. I have added a brief summary of it at the bottom of this article.

In my posts on austenitizing I described parameters of heat treating to keep grain size as small as possible and therefore improve strength and toughness [1-3]. It is very difficult to improve both strength and toughness at the same time, usually increasing one decreases the other. By what mechanism does grain refinement improve both? read more

Austenitizing, Heat Treating and Processing

Austenitizing Part 3 – Multi-Step Austenitizing

Larrin

There are many modifications to a straight high temperature austenitize for a given hold time followed by quenching. I am covering a few of them in this article.

Preheating

Preheating is performed to minimize size change, distortion, and cracking during heat treatment. Often a single preheating is recommended, but for some grades two preheating temperatures are recommended. For example, the Vanadis 4 Extra datasheet recommends a first preheat temperature of 600-650°C and a second of 850-900°C, such as in the following schematic [1]: read more