For austenitic stainless steel pipes, the hardness measured after heat treatment is 187 – where does this value come from?
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For austenitic stainless steel pipes, the hardness measured after heat treatment is 187 – where does this value come from? I checked, and neither SH3501 nor ASME B31.3 mentions it
The original poster can refer to the section on austenitic stainless steels in SYT0599-2006, which specifies the requirements for metal materials used in natural gas above-ground facilities with regard to resistance to sulfide stress cracking and stress corrosion cracking; the people who formulated this standard failed to take into account the testing requirements for austenitic stainless steels after heat treatment
The main forces behind the development and revision of standards are steel mills; the Steel Standards Committee actually has only nominal authority, and its operational funds are provided by steel mills, which is a key reason for this； Furthermore, it depends on the specific operating conditions whether certain inspection requirements for delivery are necessary for different steel grades under various manufacturing standards. For example, in the case of carbon steel pipes used for transporting fluids, cold-drawn pipes can be delivered in their drawn state, while hot-rolled pipes can be delivered in their rolled state; however, high-pressure furnace pipes and oil cracking pipes must be delivered in a normalized state. Sometimes, excessive quality standards can also be a form of waste, haha
Excess quality is also a form of waste; I completely agree. Additionally, based on the standards cited by the original poster, is it referring to the heat treatment of on-site welds in stainless steel pipes? It seems that during the installation of stainless steel pipes, less heat treatment is carried out at the construction site on the welds...
It’s not necessary for walls of normal thickness; unless the pipe wall is quite thick and multiple welding passes are required, in which case preheating is needed, along with control of the temperature difference between layers
I also searched for a long time without finding the source; I finally found out today
Many project specifications have clear requirements
I just came across a book titled “Practical Heat Treatment Handbook”, compiled by the Shanghai Heat Treatment Association; it contains information on heat treatment hardness values