weldstan
Have you confirmed the material as 347 by OES or XRF methods? Mixed alloys were somewhat prevalent in SS from China a decade ago. Poor heat treatments were also common. But at this point there is really no way to confirm.
Yes ..we have confirmed that the material is 347..However we...
mrfailure
I wonder if you still see grain boundary effects if you pulled the replica in the as-polished condition.
Great
I think we cannot see anything other than mirror image polishes surface as it has to be etched to reveal the grain and carbides.
weldstan
about 10 years.
Edstainless
If it...
MJCronin,
From China...does it matter...We found crack at the weld deposit and try to figure out whether this material is stabilized or not?
EdStainless ...If I cannot find carbides in the subgrains boundaries ..does it mean that the material was not sensitisized during operation? If we get...
EdStainless,
Thank you for the comments. It was ordered stabilized...but who knows....Can we really know if the material is stabilized or not?..Thank you very much the information regarding partial recrystallization. Based on ASTM A262, Detecting susceptibility to inter-granular attack in...
Dear all,
I am puzzled with the microstructure found in the vessel made of A240 Grade 347. We used replica technique to pick up the microstructure using 10% oxalic acid. I can see twins inside the prior austenite grains with black dots along the boundary. Are they carbides of artefact due to...
Since I had the answer to my question. I think I would like to close this tread. Thank you Mr. MJCronin for the comment and info. I really appreciate it.
"Are you sure that you have SA408 SS piping elbows and not SA 403 ? ... Please check for more typos !!!!"
Dear MJCronin,
Sorry..typo error...SA403...I have changed it....So W is for welded, thank you.
Dear all, I need some help...I come across the specification for austenitic stainless steel SA403 WP316/316LW for the fitting (Elbow) I am just wondering what is 316/316LW referring to ? Is it dual certificate 316 and 316L with W stand for welded? Any info will be highly appreciated....
This is a little bit out of topic..... Is there any beach mark (fatigue striation) on cast iron fracture surface. Anyone who has any experience looking at it? Can we see striation on ductile cast iron?
I think hardness value is a real issue when it is criteria for rejection. I think in this situation, Tensile strength should be a criteria for rejection....not the hardness.
LittleInch
Judging from the photos the rusting bit looks like the end of the reducer to the flange section which should have been under the foam layer which I can only guess got damaged as it the bit being dragged up the side of the ship time and again and created a local pool of seawater to...
Tugboat,
A partially submerged structure is the most difficult to protect as the anodes are ineffective for protecting any part that is not continuously submerged. There is the mechanical wear of being in the splash zone and the concentration of chlorides as the surface is wetted and dries...
MortenA,
Thank you for the comment.
True..Most of the pipe line subsea transporting hydrocarbon used carbon steel API 5L X60 ..X45..X65 etc and with proper CP and maintenance such Magnetic flux leak (MFL) test through pigging , the pipe can last for years. The issue is at the splash zone of the...
Thank you very much for the valuable comments,
Ironic metallurgist
Yes, the cause of the localized corrosion of the carbon steel in seawater is carbon steel in seawater.
Relying on carbon steel to contain crude oil on land is bad enough, but in seawater it is criminally negligent.
Agree...
Thank you everyone for the comments...I know that carbon steel will corrode in seawater..lol...But I expect it to be a general type of corrosion. What made it to be localized? Any idea ..pitting, crevice, MIC etc...I am sure it was not galvanic...as the zinc is well sacrificed ..Bear in mind...
