The Microstructure of Tool Steels
Tool steels cover a very wide range of compositions, from simple near-eutectoid or hypereutectoid carbon steels to alloys with more than 20 weight percent alloying elements. While there are a few tool steels grades designed to be carburized, and a few with carbon contents around 0.30 to 0.50%, most contain greater amounts of carbon, part of which can be deliberately present as graphite, while much of the carbon above what is required to achieve martensitic hardness above 60 HRC are present in carbides.
Consequently, their manufacture is complicated and their heat treatment must be carefully controlled to avoid catastrophic failures. Design and manufacturing problems can be a source of problems as stress concentrators will lead to premature failures. The webinar will give an overview of good and bad microstructures, manufacturing problems and service problems that can, and do, cause failures or reduced service life.
By attending you will learn:
- Examples of alloys prepared with 3-step and 5-step methods
- Comparison of microstructure types revealed using different etchants
- Examples of as-hot worked microstructures
- The influence of starting microstructures upon spheroidization annealing results
- Microstructures of brine-quenched carbon tool steels and of carburized low-carbon grades
- Comparison of residual carbide distributions in highly alloyed high-speed steels made by ingot casting versus powder metallurgy
- Influence of variations in austenitizing temperature on the quenched and tempered microstructure
- Examples of failed tool steel components due to improper heat treatment or manufacturing