weldstan, thanks for your reply. F91 to CS does not require pwht as per WPS. However, it's a fact that F91 welds undergo cracking if not treated well. I am trying to understand the reason why such a High Cr filler is used for F91 which has 8-9.5% Chromium?
metengr, I am studying Schaeffler diagram to understand if the weld microstructure is Austenitic or Ferritic based on its composition. Can you please elaborate a little on how this diagram can be used to select filler metal?
Hello,
I am attempting to learn welding engineering by myself. When it comes to selecting filler metals, I am aware of the considerations such as base metal matching strength, welding process and welding position do matter. I recently came across a wps where ER-347 was used in the TIG welding...
Apparently, the bushing came loose due to pressure. There was no fluid leakage through the bushing(it was wrong I said that in the first post). To me, it looks like the fluid load being applied to bellows transferred the load up until bushing making it loose. This was surprising since this being...
If the valve nameplate specifies B16.34, your valves should pass standard shell and seat tests. As an additional requirement, if you are testing with Helium, the leakage rate should be specified by the customer based on his application. Then, the valves should pass this criteria. However, this...
Hello Everyone,
I am new to the Valve industry and learning different designs and standards. Just came across Bellows Seal Gate and Globe. I read SP-117 and a few drawings and see that Bellows undergo Compression and Extension cycle under pressure. Recently, I observed leakage through Bellows...
Muktiadi, I agree with you. I found that the customer has specified Helium seat leakage criteria as per SP-61. Also, SP-61 specifies inert gas a medium for seat closure tests.
Muktiadi, some opine that Helium leakage criteria should not be taken from SP-61. Here, Helium seat leak test(low pressure leak test) is in addition to Air seat test. My question is what should be the governing criteria for this kind of Helium seat leakage test?
Hello,
If Helium seat leak test is required by a customer for a swing check valve, what should govern test duration and the leakage criteria? Gas Pressure for seat test is 80 Psi minimum as per SP-61. MSS-SP-61 gives leakage rates for seat leak tests with Air and Gas. Does that mean it includes...
Hello Everyone,
If a material(e.g.F22 after heat treatment)hardness falls within NACE requirements but outside ASTM requirements, what should govern accept/reject criteria?
Thanks