Hot tensile value

[leedrong]

Mill maker want deviation for the hot tensile value at 340 Degree C as belows.

* Material : SA 387 GR. 11 CL.2

* Tension : To be >/= 425MPA instead of >/=515 MPA

* Yield : TO be >/214MPA instea of >/=240 MPA

In general note (b) of table U of ASME sec.11 ,it mensioned that the tabulated values of tensile strength are those which the commitee believes are suitale for use in design calculations.
But mill maker quoted "It is not intended that results of such tests,if performed, be compared with these tabulated tebsile strength values for ASME Code acceptance/Rejection purposes for materials." in same general note (b) of table U of ASME sec.11

Can we use code value (515 MPA ) or to be used the value of actual tested from mill maker(425MPA ) for design calculation ?

 

[metengr]

After reviewing your post and the applicable tensile (Table U) and yield strength (Table Y-1) code values, my interpretation is that you can use the published code values. If you carefully read Note b) in Table U and in Table Y-1, the ASME Code committees of Section I, III and VIII do not require elevated temperature tensile testing as a means for acceptance or rejection of material. The last sentence of each note is important, and implies that if the test data deviates from the trend curve "by a large amount", further testing or investigation should be performed. In your case, the difference in tensile and yield strength from published code values is approximately 17.5% for UTS, and 12%, respectively.

The published values of tensile and yield strength values in Table U and Table Y-1 are trend curves, and are not based on actual production data or a statistical variation of test data. In my opinion, your actual mill production test values (assuming they meet the ASME SA 387 plate specification) are not that far off of the trend curves considering variability of heats, and plate thickness affects (you did not mention the thickness of your plate), therefore you could use the published tensile and yield strength values in accordance with ASME Section II, Part D for design calculations.

 

[leedrong]

Mr. Metengr~! Many thanks for your helpful input. We are going to proceed calculation using published tensile strength value .

 

[GenB]

I do not understand,
ussually the mill TS is stronger than published,
so since is higher you are perfectly okay at published TS,
ASME gives you the minimum and you use the tabulated values at the design temp.
ER