Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
(OP)
I am currently designing a line blank component using SA-564 Type 630 (a 17-4 PH stainless steel) in the H1150M age hardened condition. However, ASME Section II, Part D, Table 1A only lists maximum allowable stress values (S) for SA-564 Type 630 in the H1150 age hardened condition. No allowable stress values are listed for H1150M!
My question is:
Can I use the H1150 maximum allowable stress values (S) listed in ASME Section II, Part D, Table 1A when designing a component made from H1150M?
Note: SA-564 Type 630 H1150 appears as line 22 on page 46 of ASME Section II, Part D, Table 1A (2011 verision).
I realize that the elevated UTS and YS of H1150M is less than H1150, however there are no mechanical properties for H1150M or H1150D in ASME Section II, Part D. I’ve always considered H1150M and H1150D as sub-conditions of H1150 but I’m not 100% positive that the values listed for H1150 in Table 1A are intended to apply to both H1150M and H1150D as well.
Thanks in advance for any light you can shed on this request for clarification.
My question is:
Can I use the H1150 maximum allowable stress values (S) listed in ASME Section II, Part D, Table 1A when designing a component made from H1150M?
Note: SA-564 Type 630 H1150 appears as line 22 on page 46 of ASME Section II, Part D, Table 1A (2011 verision).
I realize that the elevated UTS and YS of H1150M is less than H1150, however there are no mechanical properties for H1150M or H1150D in ASME Section II, Part D. I’ve always considered H1150M and H1150D as sub-conditions of H1150 but I’m not 100% positive that the values listed for H1150 in Table 1A are intended to apply to both H1150M and H1150D as well.
Thanks in advance for any light you can shed on this request for clarification.





RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
I agree that taking the ratio of room temp TS between SA-564 Type 630 H1150M to H1150 would give me a ratio I could then apply to the elevated temperature values listed in ASME Section II, Part D (Table 1A).
Note that since H1150M is not listed in ASME Section II, Part D so I will use the values listed in ASME Section II, Part A.
SA-564 Type 630 (min TS - Table 4: Mechanical Test Requirements After Age Hardening Heat Treatment):
min TS of H1150M = 795 MPa
min TS of H1150 = 930 MPa
Ratio of H1150M : H1150 = 795 : 930 = 0.855.
Also note that the TS for H1150 listed in ASME Section II, Part D (Table 1A) is non-mandatory and is superseded by ASME Section II, Part A.
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
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Plymouth Tube
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
Yes you are correct that the ratio of YS values for H1150M to H1150 is less than the TS ratio:
TS Ratio:
H1150 : H1150M = 795 MPa : 930 MPa = 0.855
YS Ratio:
H1150 : H1150M = 520 MPa : 725 MPa = 0.717
However, ASME allowable stress values (as listed in ASME Section II, Part D or ASME B31.3) are based on 1/3 TS at design temperature. Therefore I believe it is more correct to use the H1150 values listed in Table 1A (ASME Section II, Part D) adjusted using the TS ratio (as listed above) to determine H1150M allowable stress values at elevated temperatures (i.e. 1/3 TS of H1150 values times the room temperature TS ratio of H1150M : H1150).
If I was designing a component based on 2/3 YS (ex: when calculating pipe wall thickness using ASME B31.3 Chapter IX formula) I would agree that the YS ratio should be used to convert the H1150 elevated temperature YS values listed in Table Y-1 (ASME Section II, Part D). But when working in Table 1A it seems logical to keep conversion factors in terms of TS.
Note: Elevated YS values for SA-564 Type 630 H1150 can be found on page 580 of ASME Section II, Part D, Table Y-1, line 5 (2011 edition).
Any thoughts?
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
Aaron Tanzer
www.lehightesting.com
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
For all heat treatment conditions other than H1150M, with exposure at 950F or lower, the long term strength will increase.
This does not happen with H1150M material.
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Plymouth Tube
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
EdStainless,
Just to clarify, are you saying the H1150M will not strengthen or incress in hardness over time when exposed to temperatures at or below 950 deg F? This is an attractive characteristic to aging the 17-4 PH stainless steel to the H1150M condition since in sour service applications (NACE MR-0175) maintaing low hardness is a critical defense against hydrogen stress corrosion cracking.
Do you have a good link that outlines the tensile strength, yield strength, or harness as a function of the logarithm of aging time at constant temperatures for this specific material (i.e. H1150, H1150M, and H1150D)? If so I would greatly appreciate being able to review this data.
It is my understanding that aging to condition H1150D will also prevent changes in strength/hardness over time. Would you agree that H1150D can be exposed to 950 deg F or lower without the long term strength/hardness increasing?
Thanks!
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
Is the best that I can find, but it is far less data than the original Armco alloy handbook.
There is not high temp exposure data for H1150M.
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Plymouth Tube
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
To summarize:
Neither SA-564 Type 630 Condition A, Condition 1150M, nor Condition 1150D have published elevated temperature allowable stress values in ASME Section II, Part D.
Is the use of these materials at design temperature only permissible if elevated temperature destructive tests are conducted so we have "actual" values to use during design? Seems like I'm overlooking something.
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)
ASME Boiler and Pressure Vessel code is not a clearing house for use of all materials.
RE: Allowable Stress Values for 17-4 PH stainless steel (H1150 vs. H1150M)