Does anyone know of companies that sell retractable corrosion racks that you can put multiple u-bend coupons on (we'd like to test a few different materials)? I've been searching on the internet and have only found racks for flat specimens and they can't handle multiple samples.
Please help!
Hi-
We've had problems with a heat exchanger failing from erosion corrosion near the inlet. It's constructed from carbon steel so it doesn't offer much resistance to this mechanism. We can't change the process conditions or the piping configuration so I thought it would be best to either use...
I have a question about the microstructure of A193 B6. It is listed as a ferritic steel under the spec. Isn't B6 410SS which has a martensitic structure? I'm confused as to why it says ferritic instead of martensitic. Does the heat treatment transform in into a ferritic structure?
Hi!
We are looking at putting in some new piping and filters in our new potable water system and have a few questions on material selection (our galvanized carbon steel is very corroded and we need this section replaced). The water will have a pH between 7.5 and 9.1. The project manager was...
I was asked to give choride content limits and temperature limits for welding chlorinated lines in-service. As far as I know, this should not be done at all in-service. Are there situations where it is ok to hot-tap chlorinated lines? If not, are there any codes/documents related to...
Hello,
I have always assumed that 316SS is an upgrade to 304SS. One of our mechanical engineers informed me that in some cases 304SS is more corrosion resistant than the 316SS. I was a little surprised since they are so similar. Can anyone give me any more information on this? I was reading...
Hi All,
I have been asked to see if we could substitute A334 gr.3 for a different material because of the cost and availability of this material. The equipment is designed for -100 F and 620 PSI. I haven't had much luck looking through other ASTM specs to find an appropriate substitute and...
I am a Metallurgist right out of college and am frequently asked to give a recommendation for material substitutions. Generally, I'm not 100% positive and was wondering if there is a guideline on substituting materials or if the ASTM specs include materials they could be substituted with? Any...
What are the differences in the SAE 320 L7 and LF7? Also, I could not find any information on the net using the SAE designation so it might be A 320 grade L7 (versus LF7). If anyone has information on what the F designates that would be great! Our spec says to use the LF7 grade but we aren't...
We have had some cracking issues (SCC) after we've cleaned our 316SS heat exchanger in the past. We are looking at cleaning it next week as it is fouled. Does anyone have any suggestions on caustic to use or not use with 316SS??
I recently posted a thread on pinhole leaks in carbon steel and just sectioned and mounted a sample from one of the tubes in the HVAC unit and found something interesting but confusing...
The microstructure on the OD of the tube (closest to the aluminum fins) looks different than the...
We just found multiple pin hole leaks in Carbon Steel tubing in our HVAC unit. The tubes carry 50# of steam (might have trace amounts of cyclohexlamine and hydrazine (.1-.2 ppm) at ~300 F. Aluminum fins are touching (not actually attached) the steel and most (if not all) of the pinholes are...
I recently mounted and etched a 316SS sample and it formed lines across the whole sample. I think it could be banding, can someone give me some information on this phenomena or confirm if this is banding? Also, does anyone know if it would affect the metal's mechanical properties? Finally, how...
