What is Bainite good for? 3

[Greenleader]

A general question;

I'm compiling an informal list of the best uses for bainitic steel, and some uses that are not so good. I'm taking a second look at this structure, as in Aerospace, it is generally not desirable. Thanks, Gerald

 

[metengr]

In a single sentence, bainitic steels can be best described by the formation of a non- lamellar aggregate of ferrite and carbide from austenite decomposition that exhibits the combined benefits of high strength and good toughness.

To really answer your question, I would suggest the following reading;

"Physical Metallurgy Handbook" by Anil Kumar Sinha

In his book, he devotes a comprehensive section to Bainitic Steels (9.5) pages 9.29-9.45. There is too much information to go into detail here. However, some of the highlights from his book are as follows;

- comparison of ultra low-carbon and low-carbon bainitic steels
Strength, hardness, ductility, impact toughness, fracture toughness, wear resistance, applications

- comparison of high carbon bainitic steels, applications

- weldability of bainitic steels

A second option for information is to visit the web site below.

http://www.msm.cam.ac.uk/phase-trans/index.html

There are various publications on bainite that can be downloaded for free. Once again, an excellent source of information to answer your question.

 

[Greenleader]

Thanks Metengr.

Bainite seems to have a "Reliability” problem. Very tough, but a lot of tradeoff with strength. I would love to hear of applications of differential structures in the same component in industry. That is to say, bainite/martensite combos in the same part. Thanks, Jerry

 

[CdotS]

I once was attracted towards bainite for its increased toughness, keeping the hardness at the same level. However, I have to give up on producing bainitic structures for the following reasons:

1.Money involved in converting the current martensite producing set up to bainite producing heat treatment facility. I have not done all the calculations but it looked like extra money needed to be invested which the management was not ready.
2. Need for training of workers
3. The problem of the salt bath and the associated environmental problems
4. Inability to produce bainite in thicker steel sections over 1 inch (We needed up to 4 inch sections)
5. Change resistance - why bother when something is working