The issue of the Brinell hardness value range after heat treatment of equipment in petrochemical plants
Thread Content
Hello everyone. I have a piece of equipment here (a pressure vessel) made of Q345R material with a thickness of 34 mm. The design requirements specify heat treatment, but there are no requirements regarding the hardness testing after heat treatment. At present, we have carried out hardness testing as requested by the client. I would like to ask: is the acceptable range for Brinell hardness less than or equal to 200 HB? Still less than
Are there any requirements regarding the hardness after heat treatment in the technical specifications or conditions of this equipment? What basis does the owner have for setting the hardness requirement? What is the working medium of this device?
Such requirements must be specified in the technical contract; they should be taken into account when ordering the materials. Hardness testing is necessary for welding process evaluation, and such requirements cannot be raised after the equipment has been manufactured
The technical requirements and timely conditions do not specify that hardness testing be conducted after heat treatment; however, after the equipment was delivered, the owner discovered that there were seven incorrect welds at the connection points. The equipment was sent back to the manufacturer, who was required to replace the cylinder and re-weld those seven connections. Once the equipment had been reassembled, heat treatment was carried out once again, which is why the owner requested hardness testing
The technical requirements and timely conditions do not specify that hardness testing be conducted after heat treatment; however, after the equipment was delivered, the owner discovered that there were seven incorrect welds at the connection points. The equipment was sent back to the manufacturer, who was required to replace the cylinder and re-weld those seven connections. Once the equipment had been reassembled, heat treatment was carried out once again, which is why the owner requested hardness testing
For material like Q345R, standard specifications generally do not specify any hardness limits. The material standard 24511 for austenitic stainless steel specifies hardness limits.
This manufacturer is really terrible – how can there be so many connectors in the wrong positions? This is not about conducting a hardness test; it’s about changing the manufacturer
Hahaha. . . That’s right; we won’t use this manufacturer anymore! So many mistakes were made during the takeover process; holes were even blocked, and no RT testing was carried out after that – instead, MT testing was done on its own ； After the equipment was delivered to the site, signs of blocked holes were found; the RT tests we conducted ourselves revealed defects in the form of inclusions ； Do you think such manufacturing plants can survive, especially those that are state-owned? . . . . .
It’s probably because they were trying to meet a deadline and outsourced the work to another company. Usually, veteran employees in state-owned enterprises pay close attention to quality and wouldn’t allow such poor workmanship. ;P
Hahaha. . . The issues that will arise later in relation to this matter aren’t easy to handle; the production process needs to be treated as a major equipment modification, and there’s still no decision yet