Why are hardness requirements specified for pressure vessels made of thick Q345R plates after welding?
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This post was last edited by Cuaili Yisu on 2018-7-3 at 23:01. I have a device made of Q345R with a thickness of 50 mm. The reviewer specified that after welding, stress-relief heat treatment should be carried out, followed by a Brinell hardness test, with the result to be no more than 200 HBW. I searched various standards but could not find the theoretical basis for this hardness requirement; therefore I’m posting here to ask colleagues whether there are relevant provisions in any standards or specifications regarding this requirement Thank you!
I can provide steel plates of 50 here
This post was last edited by shinaijian on 2018-6-29 at 16:34. I think it’s mainly because the plate thickness is relatively large; by testing the hardness, we can determine whether the heat treatment has achieved the desired results. In other words, hardness testing is also required when stress corrosion resistance is a concern.
I am inquiring about the regulations regarding hardness testing; I am not purchasing steel plates, thank you
Hardness testing is primarily used to assess the final outcome of heat treatment. If the hardness is too high, it indicates that the stress has not been fully eliminated; on the other hand, if the hardness is too low, it can affect the strength of the equipment.
What medium is it? In conditions involving hydrogen and hydrogen sulfide, there are specific requirements regarding the hardness of the materials and welds.
HG/T20580 has requirements for specific situations. . .
Our company requires hardness testing for those with stress corrosion resistance. However, hardness is an indicator of a material’s comprehensive mechanical properties, so it makes sense for the reviewer to require this.
Although I am a designer, I wonder what standards or regulations specify requirements regarding hardness indicators. There must be such regulations; it’s just that I may not have come across them much
Hardness limits for steel used in wet hydrogen sulfide environments per HG/T 20580-2011: Low-carbon steel HV (100≤220 (single value))； For low-alloy steel, HV ranges from 100 to 245 (single value); I am using Q345R, which is indeed a low-alloy steel. Converted to Brinell hardness, this should be around 240 HBW. So where does the value of ≤200 HBW cited by the auditor come from? I don’t understand this
What are the operating temperature and design temperature?