Charpy V Notch Test - Selecting correct impact energy values

[CJS237]

ASTM A370 specifies a range of impact energies that can be used as an acceptance criteria for a Charpy impact test. What is unclear is how it is determined what minimum absorbed energy value should be used for different materials. For example Material Spec. ASTM A352 shows in Table 1 that LCB should be tested for a minimum absorbed impact energy of 14J. Looking at another Material Spec., ASTM A479 (Stainless Steel) there are no values for the impact energy.

I am aware that a Charpy Impact Test for 316 Stainless Steel should only be performed if the service temperature is less than -196°C, but what impact energy value would be used? What is the process of selecting the correct acceptance value from Table 9 in ASTM A370?

 

[metengr]

thread330-417699

 

[CJS237]

Thanks for the response metengr. So in the case of 316 where there is no criteria in the Material Spec. or the design code (ASME BPVC VIII) the customer will decide the Impact energy?

I have read online that 316 for service less than -196°C should be tested at 41J. This is one of the values from the table in ASTM A370, but I have no idea on what basis that has been chosen. I am really trying to understand the significance of the values in A370 and what determines what value should be used.

 

[SnTMan]

CJS237, for Sec VIII, Div. 1, Part UHA specifies acceptance criteria for materials falling under this Part. Austenitic stainless steels are such a material. You will find acceptance to be based on lateral expansion of the specimen, rather than absorbed energy.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[CJS237]

SnTMan, thank you for your help however I am still struggling with this - hopefully you can provide some further information.

What would the impact testing requirement for 316 stainless steel be if the application is below -196C, say for example -210C. I presume the test would be carried out at that temperature but what about the lateral expansion values? Could you point me in the right direction in the ASME code or similar? I’ve looked at UHA-51(a)(3) for this but it talks mainly about welds but not so much about the base metal. My application does not involve any welds.

 

[metengr]

First, under Section VIII, Div 1 Non-mandatory Appendix JJ,FLOWCHARTS ILLUSTRATING TOUGHNESS TESTING REQUIREMENTS AND EXEMPTIONS FROM TOUGHNESS TESTING BY THE RULES OF UHA-51, please review Figure JJ-1.2.1 - Austenitic Stainless Steel Base Metal and HAZ Toughness Testing Requirements. If you look to the left in the flow chart is impact testing of base and weld metal if the minimum design metal temperature is below -320 deg F (-196 deg C).

The flow chart takes you back to UHA 51(a)(4) for both base metal and HAZ. In your case, HAZ is not applicable. From (a)(4)in (a)(3)each of the three specimens from each test set shall have a lateral expansion opposite the notch not less than 0.021 in. (0.53 mm). So, this applies to base metal colder than -320 deg F -196 deg C).

 

[CJS237]

Thanks metengr! That is just what I was looking for.