carbon steel grain size

In reply to #

Previous in Forum: Vanity/Shaving Mirror Manufacturers? Next in Forum: Die and Punch Clearance for Deep Drawing Process

mahesh_4754Associate

Join Date: Oct 2008

Location: mumbai,

maharashtra, india

Posts: 45

Good Answers: 3

Carbon Steel Grain Size06/09/2010 7:41 AM

Dear all,

We have a carbon steel distillation column (welded trey design) which is in caustic service. The same is made up of CS (SA516 Gr. 70 plate, 25mm. thick.) The orignal drawing of the column specifies that the grain size for the carbon steel material to be limited to 4 to 6.

The column working parameters are as follows:

Working pressure: 38.76+FV.

Working temp.: 215 C.

Can anybody tell me why the grain size of the carbon steel material is limited to 4 to 6.

Thanks in advance and regards.

Interested in this topic? By joining CR4 you can "subscribe" to

this discussion and receive notification when new comments are added.

Join CR4, The Engineer's Place for News and Discussion!

Comments rated to be "almost" Good Answers:Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!

• #2 "Re: Carbon Steel Grain Size" by Talaat Haggag on 06/10/2010 2:29 PM (score 1)

MiloGuru

Join Date: Jul 2006

Location: "Dancing over

the abyss."

Posts: 4914

Good Answers: 240

Re: Carbon Steel Grain Size 06/10/2010 8:03 AM

You'd have to ask the designer. In my experience fine grain is called out 5 or finer to astm spec.

4 is not really fine, and 5 and 6 are not considered coarse.

As a point of clarification though, are we talking about austenitic grain size or as rolled grainsize?

I'll take a look at the spec for SA516 but I don't remember such a callout ... Milo

__________________People say between two opposed opinions the truth lies in the middle. Not at all! Between them lies the problem, what is

unseeable,eternally active life, contemplated in repose. Goethe

Talaat HaggagAssociate

Join Date: Jun 2010

Location: Cairo, Egypt

Posts: 26

Re: Carbon Steel Grain Size 06/10/2010 2:29 PM

Fine-grained steels have higher notch toughness than course-grained steels. The transition temperature is lowered as the grain size

decreases. The fine-grained condition is usually due to a deoxidation practice that uses silicon, aluminium, or vanadium.

For grain size No. you can go to ASTM E112 ( GRAIN SIZE NO. 1 IS THE COURSE GRAIN , GRAIN SIZE NO. 10 IS FINE GRAIN)

__________________

Ask right person to get the right answer.

No more "Almost" Good Answers.

MiloGuru


Your facts are correct. They do not however help us understand why the spec requirement is 4-6, (both coarse and fine) and again we do

not know if we are concerned with Austenitic grainsize or as rolled grain size.

Home News &

Analysis

Products &

Suppliers

Standards

Library

Reference

Library

Engineering

Community

IHS GlobalSpec is now

Search CommunityCommunity

CR4 - The Engineer's Place for News and Discussion®

Login

CR4 - Thread: Carbon Steel ...

http://cr4.globalspec.com/thr... 4/28/2015 5:45:35 PM

In reply to #

Join Date: Jul 2006


the abyss."

Posts: 4914

Good Answers: 240

Milo

__________________

People say between two opposed opinions the truth lies in the middle. Not at all! Between them lies the problem, what is


ChrisEngActive Contributor

Join Date: Jan 2010

Posts: 17

Good Answers: 1


Given the operating temperature, could this be something to do with creep resistance? Maybe trading off against notch toughness?

__________________

[email protected]

mahesh_4754Associate

Join Date: Oct 2008

Location: mumbai,

maharashtra, india

Posts: 45

Good Answers: 3


can anybody give me a satisfactory explanation?

at least tell me what will be the probable effect of higher grain size say 8 or more on SA516 Gr.70 at the service parameters as mentioned.

this is because the plate i have procured for the new column has a grain size of 9.

regards,

MiloGuru

Join Date: Jul 2006


the abyss."

Posts: 4914

Good Answers: 240


Here's the deal, You haven't looked at the specs, so you can't get clarity. SA516 grade 70 cites SA 20 for grain size properties. I am using

copies of ASTM same caption.

ASTM A 516 paragraph 4.1 steel making practice states "Steel shall be killed and shall conform to the fine austenitic grain size

requirement of Specification A20/A 20M."

Please note it says fine austenitic grain size. That means that the grain size of 4 and 5 (coarse! ) in the range you mentioned earlier as 'acceptable' is wrong. Nonconforming. Incorrect. Out of spec. Noncompliant. Unacceptable.Disallowed. Misfeasance. Malpractice. Latent

engineering defect. BAD!

A20 paragraph 8.1 "When a coarse austenitic structure is specified... The steel shall have a ...austenitic grain size number of 1-5 as

determined by mcQuaid Ehn test." (Details uneeded to make point omitted for clarity.)

PLEASE GIVE THIS SOME CRITICAL THOUGHT 1-5 = COARSE; THEREFORE 4 AND 5 ARE ... COARSE! (THIS IS IMPORTANT!)

A20 paragraph 8.2 Fine Austenitic grain size:

8.2.1 "When fine austenitic grain size is specified, Aluminum shall be used as grain refining element unless the order provides otherwise..."

8.2.2 "When a fine austenitic grain size is specified ...the steel shall have a...austenitic grain size number of 5 or higher (finer) as determined by mcQuaid Ehn test..." (Details again uneeded to make point omitted)

YOUR ORIGINAL 'SPEC" RANGE INCLUDED BOTH COARSE AND FINE GRAIN SIZE NUMBERS. AS SECTION 8 OF A20 CLEARLY

STATES, IT HAS TO BE EITHER COARSE OR FINE NOT BOTH COARSE AND FINE AS YOUR ORIGINAL RANGE STATED!!!

That means THE RANGE YOU WERE GIVEN AS SPEC 4-6 can't properly comply to A 516 or A20.

This was the critical point in my earlier post. I am not certain why this was not understood.

If the numbers you are giving us are indeed mcQuaid Ehn grain sizes, the 9 tells me that the material is in fact AUSTENITIC fine grain ,

and most likely was aluminum Grain refined, Aluminum does a great job of inoculating very fine grain sizes finer than 7...

Fine grain improves notch toughness.

As I mentioned in an earlier post, the original grain size range you cited was ambiguous and permitted both coarse and fine

grain...something these specifications do NOT permit.

YOU REALLY NEED TO FIND OUT WHERE THAT AMBIGUOUS AND DEFECTIVE GRAIN SIZE RANGE CAME FROM!

Bottom line: The material with grain size of 9 conforms to SA 516 AND SA20 FINE AUSTENITIC GRAIN SIZE MATERIALS.

"I actually looked at the specs. I recommend this as a best practice."

For folks interested in some other factors that result from fine austenitic grain size, you may check out my blog on the subject here:

http://pmpaspeakingofprecision.com/2009/11/24/5-ways-fine-austenitic-grain-size-affects-your-machine-shop/

Milo

__________________

People say between two opposed opinions the truth lies in the middle. Not at all! Between them lies the problem, what is


Talaat Haggag Re: Carbon Steel Grain Size 06/14/2010 3:28 PM



Copy to Clipboard

Associate

Join Date: Jun 2010

Location: Cairo, Egypt

Posts: 26

I hope this notes help you

*ASME Sec. II Part A SA-516 Steelmaking practice: the steel shall be killed and shall confirm to fine austenitic grain sise requirement of

specification SA-20.

SA-20 8.2 Fine austenitic grain size

austenitic grain size number 5 or higher (finer) (not 4-6)

coarse austenitic grain size (1 to 5)

*I think the designer can adjust the minimum design metal temperature (MDMT) IF the metal produced to fine grain practice and

normalized by applying the rules of ASME sec. VIII Div. 1 UCS-66 IMPACT TEST EXEMPTION CURVES

*Also you can go to SECTION I part D TABLE 1A MAXIMUM ALLOWABLE STRESS VALUES S FOR FERROUS MATERIALS and see NOTES TO

TABLE 1A NOTES — GENERAL REQUIREMENTS

G14 These stress values shall be used when the grain size is not determined or is determined to be finer than ASTM No. 6.

__________________Ask right person to get the right answer.

Register to Reply

Interested in this topic? By joining CR4 you can "subscribe" to

this discussion and receive notification when new comments are added.

Join CR4, The Engineer's Place for News and Discussion!

Comments rated to be "almost" Good Answers:Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!

• #2 "Re: Carbon Steel Grain Size" by Talaat Haggag on 06/10/2010 2:29 PM (score 1)

Users who posted comments:

ChrisEng (1); mahesh_4754 (1); Milo (3); Talaat Haggag (2)

Previous in Forum: Vanity/Shaving Mirror Manufacturers? Next in Forum: Die and Punch Clearance for Deep Drawing Process

You might be interested in: Carbon Fibers and Carbon Fiber Cloth, Carbon, Graphite and Diamond Materials, Specialty Abrasive Grain and Finishing Media

Advertisement

"The greater the obstacle, the more glory in overcoming it." -- David Hume (Scottish Philosopher)

All times are displayed in US/Eastern (EDT) (Register to change time zone)

© 2015 IHS. All rights reserved. Reproduction in whole or in part without permission is prohibited. The information contained on this site is by users for users and is provided for information

purposes only and does not constitute advice. Any views or opinions expressed by users are personal to them and do not represent the views or opinions of IHS. You should check any information

and use your own judgment or seek expert advice before doing or not doing anything on the basis of what you read here. IHS does not verify or warrant the accuracy or completeness of any

information on this site and, to the extent permitted by law, IHS shall not be liable for any loss, damage or expense incurred by reliance on it or for any dealings you have with users or other third

parties that take place using or facilitated by this site.



carbon steel grain size

Documents