Why are impact test data at 20°C added for austenitic stainless steels in GB/T713.7-2023?
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1. The addition of impact data at 20°C is intended to enable a more comprehensive evaluation of the toughness of austenitic stainless steel at various temperatures. Although austenitic stainless steel generally exhibits good toughness at room temperature, in certain applications—such as those involving dynamic loads or impacts—it is still important to understand the material’s impact properties at room temperature. By providing longitudinal and transverse data, it is possible to gain a more comprehensive understanding of the impact performance of the material in different directions, which is very valuable information for designing and using structural components made from this material. 2. It’s better to be prepared for the worst; after all, anything can happen. In my opinion, this 20°C value is meant for use in situations where low temperatures are not a factor. It’s used when there are doubts about the quality of the product and disputes need to be resolved. 3. Personally, I think it has something to do with the effects of temperature on the properties of austenitic materials. 4.20℃ should be derived from the EU Pressure Equipment Directive. 5. Under the PED Directive, austenitic stainless steel can also be exempted from impact testing. The 6.20℃ impact test is clearly not a mandatory test; if the client requires it, it should be specified in the contract
The addition of impact data at 20°C is intended to provide a more comprehensive assessment of the toughness of austenitic stainless steels at different temperatures, particularly to understand the impact properties of the material at room temperature in applications involving dynamic loads or impacts. At the same time, this also helps to clarify quality issues in certain specific usage scenarios. The requirements of the EU Pressure Equipment Directive may also be one of the reasons; although the 20°C impact test is not a mandatory testing requirement, it can be specified in the contract if the user demands it. .
My personal opinion is as follows: 1. The impact energy at 20°C is based on EN10028-7； 2. The EN standard states that austenitic steels have good toughness and do not require impact testing; therefore, the room-temperature impact data for austenitic steel materials are provided only for reference.