The upper temperature limit for the use of Q345R (HIC) material in a hydrogen corrosive environment
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The company now has a piece of equipment with a design pressure of 3.2, a design temperature of 320°C, and a hydrogen partial pressure of 1. 76MPA, we want to use molybdenum steel, but the owner insists on using Q345RHIC. We feel it is not safe, and the Nelson curve only proposes molybdenum steel. After exceeding the limit, carbon steel and low alloy steel are not allowed. I am very worried about this. I wonder if anyone has experience in using similar equipment and has not used Q345RHIC material at such a high temperature. I hope everyone can speak freely. Thank you.
No one pays attention to it, no one is interested :'(
In this working condition, the actual solution should be "how to avoid hydrogen corrosion and hydrogen embrittlement cracks caused by hydrogen partial pressure." Therefore, hydrogen-resistant steel should be chosen after all. Q345R (HIC) is actually a steel type used for "resistant to hydrogen sulfide corrosion cracking". Its corrosion mechanism is not exactly the same as hydrogen corrosion. Q345R (HIC) not only prevents hydrogen-induced cracking but also considers hydrogen sulfide stress corrosion cracking. Therefore, my opinion is the same as that of the original poster. If it is purely a hydrogen corrosion environment, it is enough to use chromium-molybdenum steel according to the Nelson curve. However, if in addition to the existence of hydrogen partial pressure in the medium, there are also hydrogen sulfide and other media, it is better to adopt the owner's plan.
I have seen some statements that carbon steel is generally used at 220°C and the hydrogen partial pressure is below 1.4 MPa. Factors such as the medium are also considered. The poster said that if the medium is a combination of nitrogen, ammonia, hydrogen, hydrogen sulfide, etc., at 320 degrees Celsius and 3.2 MPa, it is not recommended to use 345 hydrogen-resistant steel.
First of all, thank you for your answer. Do you mean that Q345RHIC is feasible under this working condition, but it is a waste to use it here? But molybdenum steel is more expensive than this material. There is no hydrogen sulfide corrosion under working conditions. Looking forward to discussing it again with you
There is no hydrogen sulfide corrosion environment, just hydrogen corrosion environment. I also heard that this material can only be used below 200 in a hydrogen corrosion environment, but I can't find any documentation to support it.
Everyone is welcome to actively participate in the discussion. It would be better if you have experience in designing and operating similar equipment.
The key is to look at the usage temperature. The usage environment of high-pressure separators in the past was as follows:: Operating pressure 15.3 MPa, operating temperature 55 (maximum 130) ℃, medium : Oil and gas, hydrogen, H2S (0.2V%) ； The wall thickness is 92mm and the material is Q345RHIC. There is no big problem in using it.
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What I mean is that under this ambient temperature and pressure, and under hydrogen corrosion, it is better to use chromium-molybdenum steel, so be conservative.