Dear all
i have to select metallurgy for the following service :
- EtOH-H2O (90-10%) full liquid at 30bar, 170°C.
- low chloride content below 2.5ppm
- low oxygen as the system is deaerated at Tamb under ppO2=1.25mbar
- presence of 65ppm H2SO4, which would correspond to pH=2.9 in pure water.
We...
Dear all,
i could not find the answer to my question in other threads in the forum, that's why i have to ask you the following question...
ASME
PWHT of CS (P-No 1) with thickness above 125mm as per ASME VIII div. 1 (table UCS-56-1) asks for 2 hr plus 15 min for each additional inch(25 mm) over...
Dear all,
NACE SP 0170 states :
6.2 Industry experience indicates that low-carbon or chemically stabilized austenitic stainless steel weld overlays and chemically stabilized austenitic stainless steel wrought internals in reactors operating at temperatures less than 455 °C (850 °F) are resistant...
Dear all
I was given the information that the use of stainless steel 347LN should remain limited to temperatures below 450°C - for corrosion reasons -
Unfortunately, I cannot identify the type of (thermal ?) damage that may be so harmful that it would restrict the use of SS 347LN to temperature...
Dear all,
We have the requirement of specifying steel products (seamless pipe, forgings, castings, plates, tubes) with a vacuum degassing (VD) step during the steel making process.
In my opinion, final product forms are obtained by shaping (or melting for casting products) steel ingots that...
Dear Experts
We faced failures of casting version of Ni-alloy 800H (manaurite 800) after thermal ageing. Operation is at 500°C and excursions at 620°C are anticipated (coke burning). Failure was by crack propagation and no corrosion was experienced. Mechanical test of failed tubes showed total...
Dear Experts
Our client found a leaking valve in a hydroprocessing unit. Valve body material is forged stainless steel 321. Service in normal operation is hydrocarbon containing sulfur with Pop = 160bara and Top = 380°C. No water is anticipated during normal operation and also not anticipated...
Dear all,
We are designing a sour water stripper with sour water containing cyanides and chlorides. Cyanides are as high as carbon steel cannot be used, and chlorides should remain below 50ppm.
Our customer pretends that the solution "CS + clad SS 316L" is better for this column vs...
Hello
This is quite nothing, but people around me keep on using the unit "bara" for describing partial pressures.
Even if partial pressure of A can be seen as (mol fraction of A) x (total absolute pressure), i find that expressing partial pressure in bara is not relevant because partial...
Dear experts,
High tempeerature sulfidation is the high temperature (200°C+) generalized corrosion of steel in presence of sulfur containing species.
I have a note in our material selection philosophies that says :
" Stainless steels without Mo are preferable in high temperature sulfiding...
dear all
what would be the maximum tolerable corrosion rate to be controlled by application of a corrosion allowance ? (for pressure purpose, general question not liked to a particular item)
0.1 mm / y ?
0.25 mm / y ?
other ?
any ? (reference ?)
Higher corrosion rates may induce non-uniform...
hi guys !
We follow PWHT / Ni-Alloy philosophy as per NACE SP0403 for control of caustic-SCC as a function of temperature, caustic concentration and absence of aggravating factors (vaporization...).
My question is more related to generalized aqueous corrosion of carbon steel by caustic...
Hi mechanician friends
I work on "corrosion" but I also have to deal with the compatibility of materials vs. low temperatures.
Is there a clear definition for Low Temperature Carbon Steel LTCS ?
If not, what do you understand when you see LTCS mentionned ?
Thanks
hi all
Do you know where i can find a definition for "structural steel" ?
Is the construction of pressure vessels with "structural steel" is covered by interpretation of the ASME BPVC code ?
thank you
regards
Dear Specialists and Experts
High temperature sulfidation stands for the oxydation of metal (carbon steel is here under consideration) by sulfur species (H2S, R-SH, R-S-S-R', ...) at high temperature (above roughly 200°C). Even if this corrosion was extensively studied, the complete...
Dear all,
It is my company's standard practice to limit the use of 1.25Cr-0.5Mo material for pressure vessels with applications at minimum temperature above -18°C, due to the difficulties that vessel manufacturers have reaching impact test energies with this material and welded assemblies at...
Dear All
NACE TM0284:2011 document describes HIC testing and sampling of specimen in various product forms, from plates to welded pipes [...]
With regards to welded product forms, the NACE document TM0284:2011 systematically asks for sampling into the welded zone and in the heat affected zone...