Hi, Pls.refer Sec.VIII,Div.1 - UHA 44 and Table UHA-44. You should calculate the strain % as per UHA44 and if you cannot calculate,then UHA44(b) shall be applied and follow as below. According to Table UHA-44,If strain Percentage exceed 20% (for Design Temp - 580 to 675) and 10% for design temp. more than 675 degree celsius ,Head shall be heat treated (heating at the temperatures given in Table UHA-44 for 20 min/in. (20 min/25 mm) of thickness or 10 min, whichever is greater, followed by rapid cooling:) Pls. find below the extraction. UHA-44 REQUIREMENTS FOR POSTFABRICATION HEAT TREATMENT DUE TO STRAINING UHA-44(a) The following rules shall apply in addition to general rules for forming given in UHA-40. UHA-44(a)(1) If the following conditions prevail, the cold formed areas of pressure-retaining components manufactured of austenitic alloys shall be solution annealed by heating at the temperatures given in Table UHA-44 for 20 min/in. (20 min/25 mm) of thickness or 10 min, whichever is greater, followed by rapid cooling: (a) the finishing-forming temperature is below the minimum heat-treating temperature given in Table UHA- 44; and (b) the design metal temperature and the forming strains exceed the limits shown in Table UHA-44. UHA-44(a)(2) Forming strains shall be calculated as follows: (b) spherical or dished heads formed from plate: % strain = 75t/Rf(1-Rf/Ro) R f p mean radius after forming Ro p original radius (equal to infinity for a flat plate) p nominal thickness of the plate, pipe, or tube before forming UHA-44(b) When forming strains cannot be calculated as shown in (a) above, the Manufacturer shall have the responsibility to determine the maximum forming strain. In such instances, the forming limits for flares, swages, or upsets in Table UHA-44 shall apply.
(Karthik)
Karthikeyan.S QA/QC Manager Getabec Energy Co.,Ltd. 379,Moo6,Soi8,Nikhomphatana, Rayong-21180, Thailand. Phone: 0066 38 897035-8 (Off) Fax: 0066 38 897034 Hand Phone: 0066 892512282
--- On Tue, 9/13/11, asad azmi <azmiasadayub@gmail.com> wrote:
From: asad azmi <azmiasadayub@gmail.com>
Subject: [MW:12442] Requirement of Solution Annealing for SS DIshed head after forming
To: materials-welding@googlegroups.com
Date: Tuesday, September 13, 2011, 5:18 PM
Dear All, Greetings. SS Vessel is being fabricated as per construction code - ASME SEC VIII DIV 1 SERVICE : SOUR Service Material of Construction for Dished Head - SA 240 316L, 20 mm Thickness. I believe stresses will be induced in the material during forming and as a result , Sulfide Stress Cracking (SSC) failure may occur during operation. Whether Solution Annealing of SS Dished Head is required after forming? Please give reference of any International Standard. Thanks & Regards Asad Azmi -- To post to this group, send email to materials-welding@googlegroups.com To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com For more options, visit this group's bolg at http://materials-welding.blogspot.com/The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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http://materials-welding.blogspot.com/ The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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