ASME Low-Temperature Impact
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I would like to ask my seniors and colleagues for advice. I am planning to conduct a process evaluation for impact testing at -48°C. It is hoped that everything can be done in one go. The materials involved are SA-516 Gr.60(N) and SA-516 Gr.70(N), with a thickness of δ=38mm. These materials are hard to obtain in small quantities. Currently, SA-516 Gr.70(N) is intended to be replaced by SA-105(N), while SA-516 Gr.60(N) is to be replaced by either of the following materials: ① SA-266 Gr.1, according to UCS66 curve C; MDMT can be used at -48°C, but the material standard does not specify an impact temperature, and I am not familiar with this material, or ② SA-350 LF1, also according to UCS66 curve C; MDMT can be used at -48°C, but the material standard only specifies an impact test at -29°C. Alternatively, I could ask the suppliers whether their quality assurance documents require impact testing at -48°C as well In response to this, what materials do you choose when encountering such a situation?
The issues related to shock in ASME are too complex; it’s difficult to achieve success in just one step. Based on the information you provided, you have mixed up the impact requirements for weld evaluation with the exemption clause for UCS66 regarding impact. For example, in the case of an ASME product, during the design phase, if it is determined that a certain welded joint is subject to impact based on the minimum operating temperature specified by the user, then the weld evaluation specimen used to support that welded joint must undergo impact testing in accordance with UG84(g), with the testing temperature being no lower than the minimum operating temperature specified by the user. At the same time, this welded part, for which an impact test cannot be waived, also requires an impact test specimen, and the impact test must be conducted based on sampling according to UG84.
I’m not confused; I just want a system that allows for evaluations over a wider range. Otherwise, if there’s a requirement for an evaluation at -46 degrees, I’ll only be able to provide a value of -40 degrees
So, regarding the impact tests for weld evaluation, if you want to cover products that are used at -46°C, then impact tests on weld evaluation specimens at -46°C are necessary; this has nothing to do with the impact exemption specified in UCS66
It doesn’t matter; it’s just a matter of looking at that diagram to determine the properties of the steel, and to see how well it performs at low temperatures
It doesn’t matter; it’s just a matter of looking at that diagram to determine the properties of the steel, and to see how well it performs at low temperatures