Dear Prasad, I would prefer to go with 304L material for cryogenic service rather than 316 material.
J.GERALD JAYAKUMAR 00919344954677
--- On Sat, 6/5/10, N VENKATESWARA PRASAD <weldengr.velosi@gmail.com> wrote: From: N VENKATESWARA PRASAD <weldengr.velosi@gmail.com> Subject: Re: [MW:5386] RE: 5355] ER316 & E316-16 FOR CRYOGENIC SERVICE To: materials-welding@googlegroups.com Date: Saturday, June 5, 2010, 3:54 AM
Hi, You ask the manufactuer about the ferrite no in that particular batch of electrode. For cryogenic application the ferrite no shall be as less as possible. But to avoid solidifcation cracking you should have 3-5FN ferrite content in the weld. If the ferrite no is around 5 in the electrode, then during welding due to pick of nitrogen it may come down to 3 FN. Note the ferrite no. depends on the arc length of electrode. If the arc length is more, then chances of nitrogen pick up will be more, then you will have less ferrite in the weld. ( Nitrogen is austenite stabilizer) Generaly the ferrite no. changes significationly from root to cap of weld due to change in arc lengths. On Thu, Jun 3, 2010 at 9:07 AM, Prabhu Kumar L <l.prabhukumar@saipem-india.com> wrote: First of all, I would like to know why do you want to use E/ER316 filler metal for cryogenic application. No restriction that base and filler metal should be same except if application is high temperature, which requires minimum of 0.04% carbon. It is suggested to use low carbon filler metal grades in order to achieve better toughness properties at lower temperatures. I understand that the Client specification restricts only on base material for qualification purpose and not on filler material. You can use E/ER316L filler materials using SS316 base material for qualification. As per B31.3, cl. ref. 323.2.2 (f) (2) (a) and Table 323.2.2, toughness tests are required only for weld metal if MDMT is colder than -101 Deg. C. Also read note no. 2 of Table 323.2.2 for combining production weld test coupon requirements in order to meet the base metal thickness range as specified in Table 323.3.- A (5). For cryogenic application, the deposited weld metal shall have 2-5% delta ferrite in order to meet the toughness at cryogenic temperature (-196 Deg. C). More than 5% would reduce toughness on weld metal (typically it should be 2-3%). In recent past most of the manufacturers are producing duel grade materials that would meet requirements of both the grades such as SS316/316L. However, these materials cannot be used for critical applications such as cryogenic and high temperature etc, it can be used for general applications. Hope it clarifies your query. Regards, Sr. Principal Engineer, Equipments & Materials Dept., Saipem India Projects Limited, Nungambakkam High Road, Chennai - 600 034, India. Tel:+91 44 43906588, Ext.: 588, Fax:+91 44 66840345, Mobile Ph. No.: +91 9003010978. one of our Client specification says"Qualification on Material Gr.316 also qualifies for Gr.316L but not Vice versa" I want to esatblish WPS for Stainless steel Material Gr.316 (cryogrnic service) as per B31.3 whether ER316 for GTAW Process and E316-16 for SMAW will meet the Impact requirement?
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