SA-564 type 630 H1150 & Code Case 2156-1

[DavidC247]

I am intending to manufacture a Pressure Vessel Housing (cylindrical shaped over 4" Bore). I note that SA-564 type 630 H1150 requires a minimum reduction in area of 50% for material sizes up to 8". The material I intend to use is greater than 8" therefore am I correct in assuming when I conduct the additional transverse tests in accordance with code case 2156-1, then the minimum required reduction of area is 30%?

 

[AFG03082015]

Hi DavidC247

Although Code-Case 2156-1 states that the reduction-of-area shall not be less than 30%

It also states afterwards 'For those materials for which the material specification requires a reduction-of-area value greater than 30%, the higher value must be met'

 

[DavidC247]

Hi AFG03082015, Firstly many thanks for your response, I fully agree, however within SA-564 type 630 H1150, it indicates that the reduction of area is minimum 50% but it has an applicable limit up to 8"(within the mechanical test requirement table). therefore I understand material up to 8" should have a reduction in area of 50% but for material over 8" the SA-564 does not have a value so in the absence of such does material over 8" require the code case value of 30%?. The code case states reduction of area shall be minimum 30% unless the material specification requires a larger value, for material over 8" the SA-564 type 630 H1150 does not have a value?

 

[AFG03082015]

I see your point David,

I would assume that the values in the mechanical properties table are valid up to 8" bar and the values above that may be lower than stated and would have to be accepted with a concession. Personally I would still want the material over 8" to meet the 50% ROA, and through personal experience such material does exceed this value.

However, I could be very wrong and hopefully someone else on the forum will be able to enlighten us...

 

[metengr]

The dimensional limits for ASME SA 564 material specification are as stated for a reason. Which means if you purchase material that exceeds 8" diameter, the SA-564 material specification is not applicable for mechanical properties. You do not default to an ASME Code Case if this is the situation to justify use of wrought material that is supplied outside of the scope of the material specification.

The ASME Code Case was issued to address using bar in pressure retaining applications and as part of this use, there are additional testing requirements to follow. However, this cannot be used as card blanch for material that is not within the scope of ASME/ASTM.

I would suggest you review ASME Section VIII, Div 1 pressure retaining materials and look into a forging rather than bar to accomplish what you need.

 

[AFG03082015]

Hi metengr

Could it be possible though that certain Authorized ASME Inspectors would approve the use of bar with OD greater the 8"?

Thanks

 

[metengr]

AFG03082015;
For certain applications AND the material specification has listed mechanical properties for the wrought product dimension. In your case, where are the allowable stresses going to come from regarding this material above 8" diameter?

 

[DavidC247]

I assume S17400 H1150 is used above 8" diameter, within the Section II Materials for 17Cr-4Ni-4Cu the forging spec is SA-705, this has the same limitation up to 8"?

 

[DavidC247]

Looking at both specifications SA-564 & SA-705 the material test direction is Longitudinal, the code case test requirement is Transverse. I have been advised that the UTS & Yield can still be maintained on larger diameter Bar, thus apply the ASME rules, my design stress could be defined, but the material is unlikely to achieve the minimum 50% reduction in area in the Transverse direction, but as noted the specifications which define the 50% reduction is in a different direction.

 

[metengr]

Good option. The material specification limit is 8" thickness and not diameter.