Very short and very long heat treatments for steel
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- Опубліковано 16 гру 2024
- A talk given at the meeting of the International Federation of Heat Treatment and Surface Engineering, during April 2016, at Savannah, Georgia.
There are significant processes emerging where the heat treatment times can be as long as 10 days or shorter than 100 ms. In both of these examples, extraordinary properties are achieved which have made the treatments commercially viable. Heat treatment involves the thermally activated movement of atoms into lower energy configurations. Therefore, the time-scale of the heat treatment depends on the choreography of the atomic motions, whether the motions are coordinated or not. It is demonstrated that remarkable structures can be generated by controlling these mechanisms, including structures that have never before been observed or generated on a scale that is large enough to exploit.
Http://www.msm.cam.ac....
very interesting lecture.flash bainite,very short heattreatment. why the bainite is ductile than tempered martensite at same strength?
+M. Tim It does depend on whether the martensite is tempered or not. If not, then carbon in solid solution reduces it toughness dramatically.
+bhadeshia123 why lower bainite is ductiler than tempered martensite at the same strength?
+M. Tim Is it?
+bhadeshia123 I think it's why people pursue the bainite microstructure in application.
Prof. Bhadeshia, the potency is proportional to time.why the martensite propeties change rapidly in the initial one hour when doing the tempering heattreatment, then prolonged time has little influence?
The initial stage relieves excess carbon, which otherwise is the biggest contributor to martensite strength.
after the initial stage relieve most of excess carbon, can the residual carbon be relieved if hold longer time at the same temterature? and is the driving force become smaller as tempering time goes?
yes
Nice Job, Prof. Bhadeshia. I have a question to the micrograph (24 min). You have a mixture of austenite, bainitic ferrite and martensite. But what are the black tiny parts in the micrograph? I ask because I also have this effects after preparation but much more. Have you any idea?
+Jens Liefeith I am not completely sure.