Please Explain Austenite & Ferrite

Date 02-16-2013 18:19

Studying for the CWI is a monumental task.
When you review the body of knowledge that the CWI exam is drawn from, it is massive and would take years to read every single word of it. AND much of it is beyond understanding for most of us mortal welders.
For quick advice, Wikipedia is your friend. If you read it's article on Austenite, it does not contain the word Austenitic, these are different terms, sorta kinda.
The Austenite phase of low carbon steel such as A36 does not exist at room temperatures, nonmagnetic, just like a blacksmith when quench and tempering will test a tools heat with a magnet before quenching.
Here's a short list of definitions you might find helpful.
http://www.toolingu.com/definition-500230-18105-austenite-phase.html
As is with so many terms in science and technology, most of these definitions contain words requiring further defining. Like trying to organize the hobby bench in the garage. Each item you clear off the shelf leads to organizing another tool box or shelf.......
Fun aint it? Gawd! I LOVE this stuff...

By welderbrent (*****)

Date 02-16-2013 18:41 Edited 02-16-2013 20:31

You have me curious about a couple of things there Hack,

Do you mean you have figured out Cementite, Pearlite, Bainite, and Martensite, BUT, not Austenite and Ferrite? Or, you are only concentrating on the two without regard to the others?

Which study guide are you referring to? Does it include a phase diagram? Does it include information on Phase Transformations and Lattice Structures?

You will need a good reference on Metallurgy to answer these questions you have asked. There are many. I was just curious as to rather it was in the study guide you mentioned. It would take even Henry a great deal of space to properly answer your questions. Easier to just point you to some easy reading material.

Interesting you would even ask here with the low view you expressed on trying to get a clear answer from the inspectors here. And it's such an easy, no-brainer job being an inspector. We don't have to know anything about metallurgy and the like. :confused:

Have a Great Day, Brent

By Superflux (****)

Date 02-16-2013 18:55

Awww, c'mon Brent.
You know Darned well that all Inspectors have to know is how to carry a clipboard and impose stupid rules on those poor know-it-all Welders.

By 46.00

Date 02-16-2013 19:16

I had a couple of ferrits years ago, smelly animals! :grin:

By 46.00

Date 02-16-2013 19:40

To be serious, both Austenite and Ferrite are Iron. Austinite is a gamma phase iron and Ferrite is an alpha iron. Their crystal structure is different (FCC against BCC). Austenite is an allotrobe of Iron that is able to dissolve much more carbon than other allotropes of Iron.

Google is your friend!

By hacksaw (*)

Date 02-16-2013 22:36

You said:

Do you mean you have figured out Cementite, Pearlite, Bainite, and Martensite, BUT, not Austenite and Ferrite?

Yes.

Interesting you would even ask here with the low view you expressed on trying to get a clear answer from the inspectors here. And it's such an easy, no-brainer job being an inspector. We don't have to know anything about metallurgy and the like.

You've never seen the things that I've seen from inspectors on jobs before. I've seen them call good welds bad, and bad welds good, and everything in between.

By ssbn727 (*****)

Date 02-17-2013 07:24 Edited 02-20-2013 16:48

Hacksaw!

You got good and bad everywhere you go in this world these days just as they were in the past...
However, You just don't come in here badmouthing every inspector in here and then come back asking us to help you without at the very least showing some hint of remorse :evil:

I hope you learned something from this but, judging from what you posted as your second response - it sure doesn't look that way!!!

Now that I got that out of the way, "WELDCOME TO THE WORLD'S GREATEST WELDING FORUM!!!"

I'm going to give you a gift... Just remember where it came from and from now on treat people here and elsewhere with Respect and you'll go a long way son. :twisted:

The title of this book is "Steel metallurgy for the Non- metallurgist" Here's the link:

*edited out the link*-moderator
Then look under the book's title and you'll see where you find the link that says "Download .pdf"

Respectfully,
Henry

By Shane Feder (****)

Date 02-17-2013 08:01

Henry,
Great reply.
Regards,
Shane

By Superflux (****)

Date 02-17-2013 15:59

Henry,

Thanks for that FREE download. I've been wanting this book for quite sometime, and keep forgetting to buy it.

I've often said that being QC is like a prison guard. After a while you don't trust the nice ones.

By welderbrent (*****)

Date 02-17-2013 21:56

Henry,

Once again your vast resources have stepped up to the plate to help all of us. I also have downloaded from your link. Took a minute to glance through and it is a very interesting resource. I have heard the title but never had the chance to look it over. Now, I have it in my reference library. Thank you.

Hack,

Awfully presuming of you to think you are the only one who has ever experienced a bad inspector. I have worked as a Boilermaker, heavy equipment repairman/welder, pipefitter, structural welder, manufacturing welder, and company owner during my 40 plus years in this trade/profession. I have experienced some bad inspectors during that time. But they have been considerably fewer than the good and reputable ones. There will always be room for improvement. There will always be misconceptions, misinterpretations, misapplications, misinformation, etc. But that is no excuse for your previous rant against ALL inspectors. Especially after one has been actively employed and working as a welder and then becomes an active inspector and has the opportunity to learn several of the various aspects of that position we learn how easy it is to make blanket statements that are not as applicable to reality as we thought when we were busy criticising what we did not fully understand.

Once you get through the exams and become an inspector, I hope you learn quickly the true application of the codes and how to apply them without bringing the public into danger.

Have a Great Day, Brent

By 803056

Date 02-19-2013 01:39

You can lead a horse to water, but you can't make it wear a bikini.

Ferrite - magnetic, no carbon, body centered cubic at room temperature.
Austenite - nonmagnetic, face centered cubic, at high temperature, carbon is in solution.
Martensite - magnetic, supersaturated with carbon at room temperature, body centered tetragonal, product of rapidly cooled austenite.
Pearlite - magnetic, matrix of ferrite with lathes of cementite, product of slowly cooled austenite containing 0.8% carbon.
Tempered martensite - martensite that has been tempered, some excess carbon allowed to precipitate as carbides, softer than martensite, but still relatively hard depending on the tempering temperature.

Al

By eekpod

Date 02-19-2013 11:21

Hacksaw.
From what I remember from taking my CWI and also my notes from studying for it, what Al has just posted above is all you'll need to know about the metalurgy. I specifically remember the BCC body center cubic part. I don't recall if it was on the test as it was almost 18 yrs ago, but becasue that information was so new to me that I felt compelled to study it. Of course I never needed it again as a shop QC inspector :wink:

But it's good to know and as your career evolves you'll hear those terms and you need to understand what they are, and where you can get more in-depth info if you need it.
Good luck
and thanks Al for breaking it down and the info.

By 803056

Date 02-27-2013 16:47

Evidently Hacksaw didn't find our help very helpful after all.

Good luck Hacksaw. Where ever you are. Don't loose that stinger. You might still need it.

Whatever the outcome of your CWI examinations, you will not know less than you did before studying for the examinations.

Al

By Laura Date 03-04-2013 08:06

Austenite, also known as gamma phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron, with an alloying element.[1] In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1,000 K (1,300 °F); other alloys of steel have different eutectoid temperatures. It is named after Sir William Chandler Roberts-Austen (1843–1902)