Why must high-pressure oxygen pipelines be made of stainless steel?

During its flow in pipes, hyperbaric oxygen tends to react with active iron; therefore, ordinary steel cannot be used for its piping. According to foreign studies, if the flow velocity of oxygen in the pipeline exceeds 20 m/s, sparks will occur within the pipeline; therefore, high-quality materials must be used to prevent excessive oxidation.

For the safety requirements of hyperbaric oxygen pipelines, steel with low carbon content must be used; even gaskets should be made of tetrafluoroethylene, and graphite wound gaskets are not permitted. Graphite seals cannot be used for valve sealing either, and thorough degreasing is required before use.

Hyperbaric oxygen pipelines must be made of stainless steel, especially those used for transporting high-pressure, high-purity oxygen. In China, it is stipulated that the flow rate of oxygen in such pipelines should be below 10 m/s (this is also a requirement set by Texaco). The reason for this is that high flow rates can cause pipes made of materials less resistant than stainless steel to oxidize or even burn. In pipelines carrying high-purity oxygen at flow rates above 10 m/s, materials more resistant than stainless steel, such as Monel alloy, must be used

Oxygen pipelines should preferably be made of SS. For the following areas, it is advisable to consider upgrading the material to Incloy or Monel: 10D behind the orifice plate ； Behind the valve ； After the elbow ； A rough rule: Pressure inside the pipeline × gas flow rate

Compressed high-pressure oxygen has characteristics such as high purity, high temperature, and fast gas flow rate, which make it prone to chemical reactions with elements like hydrogen, iron, and carbon present in ordinary carbon steel. This can affect the service life of the pipelines and pose risks; therefore, stainless steel pipelines made from this material must not be used for oxygen pipelines.

High-pressure oxygen pipelines must be made of stainless steel. Generally, the oxygen flow rate within such pipelines should be below 8 m/s; ordinary stainless steel can be used for this purpose. For pipelines carrying high-purity oxygen at flow rates above 10 m/s, materials such as Monel alloy or Inconel should be employed

This post was last edited by Tianya Langji on 2009-5-2 04:40. I noticed that you are referring to flow rate rather than volume. I work for Texaco; before driving, we have to inhale oxygen, that is, we set the oxygen flow rate in advance and release oxygen. Due to the high oxygen pressure, the flow rate during venting is not high, but the velocity should be very high. Does anyone know any information on this topic?

Does anyone know the flow rate range for high-pressure coal gas?

Take Texaco as an example; it seems that the valves related to oxygen use RJ flanges, so the gaskets are likely metal ring gaskets.

In a pure oxygen environment, the ignition point of almost anything decreases, making combustion possible (including metals); therefore, it is necessary to prevent temperature changes. Hyperbaric oxygen pipelines must be made of stainless steel to prevent explosions caused by impurities.

May I ask whether 304 seamless stainless steel tubes can be used for hyperbaric oxygen tubes? If it is to be adopted, what aspects need attention?

Upstairs, high-pressure oxygen must not be used with pipes that have seams； The codes for pressure pipeline design specify this ； Seamed pipes cannot be used for high-pressure pipelines

It seems that we need to conduct a more in-depth discussion on the oxygen pipelines!

SS for the pre-XV03.XV04 oxygen pipeline, Incloy625 for that after XV03； All oxygen pipeline flanges are RJ; gaskets are not possible. Last edited by wenyb-15 on 2009-4-27 11:07.]

What do XV03.XV04 mean? Is it necessary to use INCOLOY825?

XV03.XV04 should be the first and second shut-off valves for the oxygen pipe.

The material selection for oxygen pipelines can refer to various international or domestic standards: 1. Currently, it is required that oxygen be free of particles, as any particle colliding with the pipeline could lead to a fire in the pipeline. No matter what the purity of the oxygen is, it is impossible to have absolutely no particles. Therefore, the material selection for oxygen pipelines is very important. 2. Pipeline oxygen combustion is related to the material of the pipeline, as well as the purity, pressure, temperature, and flow rate of oxygen. So oxygen combustion does not occur under all conditions. 3. When selecting materials for oxygen pipelines, other factors must also be taken into account: the fluid flowing within the pipeline. For example, the material selection for a pipeline carrying a mixture of oxygen and nitrogen differs from that for a pipeline carrying pure oxygen under the same conditions. The safest advice is to select materials in accordance with international standards.

High-pressure pipelines are not made of stainless steel; they are made of nickel alloys, and degreasing is required before use.