I have a question regarding the material of hydrogen pipelines

1. SH/T3059-2012 stipulates: In Article 6.3.3, “For carbon steel and alloy steel pipes whose operating temperature is equal to or higher than 200°C and which contain hydrogen in the medium, appropriate hydrogen-resistant steel materials shall be selected based on the Nelson curve, taking into account a margin of 20°C to 40°C added to the highest operating temperature of the pipe, as well as the partial pressure of hydrogen in the medium.” ” Article 6.3.4: For pipelines whose operating temperature is 250°C or higher and whose medium contains hydrogen sulfide and hydrogen, the selection of pipeline materials shall be determined based on the pipeline’s operating temperature and the hydrogen sulfide content in the medium, in accordance with the Couper curve. ” 2. Here, it is assumed that your medium is pure hydrogen, free of hydrogen sulfide. The design temperature is 450°C, and the design pressure is 4.5 MPa. (Because the description you provided is incorrect: \"The most severe operating conditions are an operating temperature of 450°C and an operating pressure of 4.5 MPa.\" The most severe operating conditions should be the design conditions, not the actual operating conditions.) ) Chromium-molybdenum steels such as 1Cr5Mo and stainless steel materials such as 321 can be used. 3. If it is not the condition in 2, refer to 1 for material selection.

Thank you! I’ve basically never used 321 material before. Common pipes are 20#, 304, and 316. I’ll check the information again.

This post was last edited by *xuegui2hao on 2016-3-29 at 15:50. It is recommended to use material 321; this material is commonly used in high-temperature hydrogenation applications. 1Cr5Mo is generally used in situations involving high-temperature sulfur corrosion.

Provided that both temperature and hydrogen partial pressure meet the requirements, 1Cr5Mo can also be used as an option; however, care must be taken in processing the material to prevent temper brittleness. Of course, since the operating temperature in the owner’s case is high, choosing 321 is definitely no problem at all; it is indeed the preferred choice.

The second floor is supported; in terms of cost, 1Cr5Mo is superior to 321. When it comes to material procurement, 321 is more readily available than 1Cr5Mo. If the quantity required is small, 321 can be considered as a preferred option. However, if the quantity is sufficient and 1Cr5Mo can meet the required performance conditions, it is recommended to have pipes made from 1Cr5Mo. This is merely my personal opinion

You can check the Nelson curve. For the above operating conditions, I think 1Cr5Mo is better. If hydrogen sulfide is present, it is recommended to refer to SH/T 3129 and SH/T 3096; I choose the materials for hydrogenation processes based on these two standards.

Use 321; it’s easy to obtain and not expensive, and any issues that arise during use are easy to resolve.

Choose hydrogen sulfide-resistant pipes!

No, no – titanium-containing stainless steel pipes, type 321, should be chosen