JB4732-1995 (2005)
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The last edit to this post was made by gbj_hebut on 2015-10-19 at 18:16. According to 10.2.5.3 of JB4732-1995 (2005), under any circumstances, the design stress strength of the reinforcing metal shall not be less than 80% of the design stress strength value of the wall metal at the design temperature. The Q345R shell + 304 forged nozzles may not meet the requirements; at 150°C, the design stress strength of the former is 183 MPa
The shell is made of Q345R, while the nozzles are made of 304 – this doesn’t seem very reasonable. Could the original poster explain this?
It wasn’t explained very clearly; the shell material is a composite plate of Q345R and 304. Due to the small size of the nozzles, it’s not feasible to use 16Mn with surfacing welding, so 304 forgings have to be used for the nozzles. As a result, the design stress intensity of the takeover is 80% lower than that of the shell. At this point, it is equivalent to using thick-walled pipes for reinforcement, but the properties of the reinforcing metal materials do not meet the aforementioned requirements.