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NBrink, I agree that though first stage is called Dry & Hot, there is a always presence of smaller quantity of water due to shock condensation... Even then will you prefer inject amine in the first stage??

Greetings, In a Crude column overhead section with two stage cooling system i.e. First stage operated hot and dry with condensed Hydrocarbon refluxed back to the column. In second cold stage water + hydrocarbon is condensed. In such system which location is ideal for Neutralizing Amine...

Thanks for the rply, Yeah I am aware of the API 934B guidelines. Can you please share your field experience in using Austenitic stainless in REAC upstream piping. The major corrosion mechanisms which plays key role in Metallurgy selection for these sections are: 1. NH4HS corrosion 2. NH4Cl...

Greetings, I want to get clarified on few things on selection piping metallurgy for the inlet of Reactor Effluent Air Condenser [REAC] for Hydro processing Units i.e Hydrocrackers & Hydortreaters. 1. Is anybody is using Austenitic Stainless steel [300 series] in these sections? 2. If yes,what...

Sjones, Thanks for the reply

DVWE, Thanks for reply.

Metengr, Agreed. Its understandable that "Stress" Plays a role in "Stress" corrosion Cracking & Sulfide "Stress" Cracking. But my question is, is residual stress generated during normal welding practice is a determining factor in SSC? if yes, then why PWHT is not mandated in NACE for carbon...

Greetings, I want to get clarified on PWHT requirement for seamlesss carbon steel piping [not equipment] to avoid Sulfide Stress Cracking [SSC] in refinery sour service. As per NACE SP 0472 & NACE MR 0103, PWHT is not mandatory requirement for carbon steel to avoid SCC. Hardness control is the...

McGuire, Thank you... I want to read further on the solid states physics theory of the passive films which you explained earlier. Can you please refer the literature or book which I can buy. Thank you

McGuire, Thanks for the very informative post. Its new! Though late for the post, I want to get clarified on few things on role of Nickel in Chloride stress corrosion cracking. I have read in some of the books on corrosion of stainless steel that, boiling MgCl2 testing has shown that minimum...

Metengr, Thank you...

Greetings, I was going through the 2014 version of ASME B31.3. Major changes have been made, especially in Para.330- Preheat & 331-Heat treatment. I want to get clarified on the following: 1. What is the rationale behind setting 600 deg F/hour [divided by 1.5 times the thickness in inches] as...

Thank you XL83NL, The line operating pressure varies between is 15 to 50 Psi depending on the operating case and design pressure is 100 Psi. The operating temperature varies between 1175 deg F to 1200 deg F. The design temperature is 1250 deg F. The size of the flange is 42" and 50". So its not...

Metengr, Thank you. I want your opinion on the following 1.But there is a subtle difference in the Chemical compostion [Carbon, Aluminium + Tiatanium] of UNS N08810 (800H) & UNSN08811 (800HT) to enhance the creep strength. I could not find stress value in both ASME Section II part D, Table-3...

Greetings, I was reviewing a piping specification for high temperature austenitic stainless steel operating at 1200 deg F [635 deg C].But the operating pressure is low [1 kg/cm2]. The metallurgy for the bolt material specified is SB 408 UNS N08811. This bolt material is not listed in [Design...

Weldstan, My understanding is SA 106 GR B is intended for high temperature applications. Is it not killed with silicon for coarse grain practice? [but its not mentioned in the specification].I am curious to know then what makes SA 106 a specification for High temperature application.Can you...

Metengr, Thank you...

once again thank you. 1.If there is no threshold for grain size for pipe to consider it as "fine grain" then how to ensure the fine grain manufacturing practice? 2. Why the definition for fine grain should be different for plate and pipe? [for my academic interest]. SA 671 is pipe...

Thank you Metengr.. Yes. Impact testing would be the best way to to sort it out. But the pipe spools are already fabricated and errected in the field. This was identified during final inspection. Now the contractor has taken some insitu metallography and screening /segregating the pipes with...

Greetings, Memebers please clarify the following: 1.SA 333 specification does not “explicitly” specify the fine grain requirement for GR 6 pipe. If I want to check the same, can I use the criteria that carburized austenitic grain size number of 5 or higher (finer) as determined by the...