faris12
Chemical
- Jun 7, 2003
- 1
Hi
I’m glad to share the following hint regarding valve bonnets bolting selection and the need to hard face Monel 400 seats.
Recently, a valve vendor supplied a bolted bonnet valve using 300 SS series. The application was brine water in relatively marine environment and AMB temp. This was happened because usually bolting system if left to the manufacture. As alternative, the bolting system has been changed to B7 Teflon coated bolts. Bare B7 bolts could be used but bolt change is to be expected some time after 5-7 years, based on the external environment.
The same vendor was unclear about the need to hard face the valve seat with Monel for erosion during valve throttling. Monel 400 is not specified for erosion protection, the Monel valve Monel internals was going to provide the adequate corrosion resistance in brine service, the elimination of the re-work to overlay the seats saved a lot of our project budget.
Please feel free to share your experience and feedback, especially using 300SS bolting on marine environment, and did you experience any case history of chloride SCC.
Faris
Corrosion/RBI engineer
I’m glad to share the following hint regarding valve bonnets bolting selection and the need to hard face Monel 400 seats.
Recently, a valve vendor supplied a bolted bonnet valve using 300 SS series. The application was brine water in relatively marine environment and AMB temp. This was happened because usually bolting system if left to the manufacture. As alternative, the bolting system has been changed to B7 Teflon coated bolts. Bare B7 bolts could be used but bolt change is to be expected some time after 5-7 years, based on the external environment.
The same vendor was unclear about the need to hard face the valve seat with Monel for erosion during valve throttling. Monel 400 is not specified for erosion protection, the Monel valve Monel internals was going to provide the adequate corrosion resistance in brine service, the elimination of the re-work to overlay the seats saved a lot of our project budget.
Please feel free to share your experience and feedback, especially using 300SS bolting on marine environment, and did you experience any case history of chloride SCC.
Faris
Corrosion/RBI engineer
