Reduction of Tensile Strength with PWHT 3

[Montana1]

I am in need of some data for predicting the reduction of tensile strength in 2.5" thick SA516-70 normalized at varying PWHT times. I have read on some threads about the Hollomon-Jaffee Parameter, but I haven't had any experience with this equation. Can someone help me out?

 

[tc7]

Until somebody comes along that can better understand your question, in a pinch you might take a look at the strength vs. draw temps charts for AISI 1030 which is ~close to your SA516 in Bethlehem Steel "Modern Steels" book. This won't answer your "time at temp" question, but you could also look at the ASM "Atlas of I-T and C-T Diagrams" or other references mentioned by Corypad in thread#330-198668. These charts will give you hardness information that may get you whatever you're looking for. There is some other excellent links in that thread as well.

 

[metengr]

You don't need to go this route. The data is available regarding reduction in TS as a function of PWHT time and temperature in plate product literature

http://www.mittalsteel.com/documents/en/Inlandflats/ProductBrochure/low sulfur clean.pdf

 

[metengr]

Sorry about that, I forgot one other link

http://www.mittalsteel.com/document...tBrochure/mittal pressure vessel brochure.pdf

 

[tc7]

Hi Met-
I knew you would be along soon enough. That second .PDF is great. But on page 2, it refers to a "Plate Steel Specification Guide" with a link that doesn't go anywhere. If you get in to

http://www.mittalsteel.com

or the ArcelorMittal website there isn't any way to get Mittal technical publications. Can you help us find that Guide?

 

[metengr]

http://www.ispat.com/documents/en/I...ication/ArcelorMittal_SPEC_GUIDE_20070801.pdf

 

[Montana1]

Thank you all for the good responses to my question. Mittal has some great literature for answering my question; however, I would like to find a more detailed answer regarding the mechanism for reduction in tensile strength with increased PWHT time. Am I safe to assume that the normalized microstructure gets tempered over time and loses some of its strength? Also, why does Mittal use Larson-Miller Parameter in their data? I thought this equation was for material that ruptures under a constant stress at a given temperature. Would it be better to use the Holloman-Jaffe Parameter?

 

[metengr]

Am I safe to assume that the normalized microstructure gets tempered over time and loses some of its strength?

Reply; Yes

Also, why does Mittal use Larson-Miller Parameter in their data?

The time/temperature effects on tempering can be described using either LM for strength or HJ for hardness because these parametric equations provide the best correlation to plotted data.