Can 08Ni3D forgings be used when the temperature is above 20°C?
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For 08Ni3D forgings, GB150.2 specifies that the upper limit for the allowable stress at temperature is ≤20°C; there is no allowable stress above 20°C. Does this mean that it cannot be used at temperatures higher than 20°C? Previously, I encountered a process package that required a design temperature of -75/50°C. The final solution was to manually add the allowable stress at 50°C (based on the data at 20°C). I think the standard here might be wrong? 20°C is indeed too low.
08Ni3DR has data at 100°C in GB150.2, so 08Ni3D forgings should work as well, right?
Yes, the sheet metal has data at 100°C, while forgings do not; forgings only have an allowable stress of 20°C.
I’m not sure how the standards are determined; this material was developed to replace the 3.5Ni low-temperature carbon steel used in the 203E model. But it can’t work at 20°C either – in any case, it’s sufficient to add it manually at temperatures below 100°C. It’s definitely not possible to avoid using this material just because the temperature is a little higher; what else could be used in such cases?
I think it can’t be used unless it has been verified; you can’t make decisions arbitrarily – there must be a basis for it.
The intended use of this forging is for low-temperature applications; it is sufficient to ensure that the operating temperature of the equipment is low. The 50 degrees in the design temperature, in my opinion, takes into account all operating conditions, such as the situation when the system has just been put into use and its temperature has not yet dropped to the operating level.