Old Material Mechanical Properties 2

[eng741]

Hi all,

I am searching for ASTM A-89 Grade B steel yield strength.

The pressure vessel was initially constructed with the 1943 UPV code and uses that material. I know the tensile strength and the allowable stresses at given temperatures from the 1943 code book but cannot find the yield strength. Also, I could not find
A-89 Gr. B in ASME sec. 2 part D.

Would anyone happen to know a rule of thumb to find the yield strength, or a formula that ASME provides.

Thank you all in advance,


eng741

 

[EdStainless]

I presume that A89 does not list required yield strength?
These are very low strength alloys, right?
Some of these materials have very low yield strengths.
What were the allowed stress rules in '43? What fraction of UTS or Yield was used?



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P.E. Metallurgy, Plymouth Tube

 

[eng741]

SA-89 Gr. B

Spec. minimum tensile = 50,000 PSI

maximum allowable working stress
-20 F to 650 F = 10,000 PSI
700 F = 9600 PSI
750 F = 9000 PSI
800 F = 7500 PSI
850 F = 6000 PSI
900 F = 4400 PSI
950 F = 2600 PSI
1000 F = 1350 PSI
1050 F = -----

The stress goes no further than 1000 F and I could not find anything to find/calculate the yield strength.

 

[TGS4]

At that vintage, the design margin was 5 on ultimate. That corresponds with the allowable stresses (which would have been directly in Section VIII). Considering that the margin on yield had always been 1.5, if I were you I would assume that the yield at temperature is 1.5 times the allowable stress. At least up to ~850F. Above that you're into creep, where short-term yield is meaningless.

 

[eng741]

Thank you TGS4,

Out of curiosity how did you know the margin of yield is 1.5 times the allowable stress at the given temperature?
Is it a rule of thumb?
I am always interested in little tips that you provided so I can become more knowledgeable.

Thanks for all the help,

eng741

 

[r6155]

eng741, see BASIS FOR ESTABLISHING STRESS VALUES in ASME II Part D
Regards
r6155

 

[eng741]

Thank you r6155 I found it!

Thank you all again for the help,

eng741

 

[TGS4]

eng741 - r6155 is correct for current Code. For the old Code, you would need to look at that old Code; putting the allowable stresses and allowable stress basis in II-D is relatively recent.

 

[Murec]

I understand that the factor for allowable stress was reduced from 5 to 4 during the war (1942-1946) to save on materials. It went back to 5 until 1950, then became 4 and is now 3.5 (since 1999) - from a FFS-1 course I took recently.

 

[eng741]

Thank you all for the help

eng741

 

[TGS4]

Murec is correct. And the margin on yield at temperature has always been 1.5.

 

[Christine74]

I think Murec must be referring to the API-ASME code, not the ASME code. As you can see from the allowable stresses in the 1943 edition of the ASME Unfired Pressure Vessel code, the design margin is 5 to 1, not 4 to 1:

https://law.resource.org/pub/us/cfr/ibr/002/asme.upv.1943.pdf

-Christine

 

[eng741]

I thought the design margin was based from the yield strength and not from the tensile strength?

Also, the 1943 unfired pressure vessel link that Christine74 shared (thank you by the way) can you find more information on SA-89? Such as the yield strength, chemical composition, and what metal(s) can be welded to that material. If not where could I find that information.

Thank you in advance,


eng741

 

[EdStainless]

It is an either/or situation, such as 2/3 of yield or 1/4 of UTS whichever is lower.
Those fractions have been various things over the years.
There are specs that have required UTS without a yield requirement.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[jte]

As Christine74 mentioned, the 1943 API-ASME code is different than the 1943 ASME code. In the API-ASME version, A89-B has a Maximum Allowable Working Stress in Tension of 12,500 psi at 650°F, with values listed up to 1000°F (3,100 psi).

From ASME II 1940, Spec. S-2 is identical with ASTM A89-39. For the Firebox quality Grade B, chemical requirements are:

[pre]Carbon, max % (plates less than and equal to 3/4") 0.20
(plates over 3/4" thick) 0.22
Manganese, % 0.35 to 0.60
Phosphorous, max, % (acid) 0.04
(base) 0.035
Sulphur, max, % 0.04[/pre]

Tensile strength is 50,000 psi min, 65,000 psi max
Yield strength is 1/2 tensile strength but not less than 27,000 psi

 

[eng741]

Thank you all for the help