Hello, Can I know which dia electrode was used at 6 O'CLOCK & 12 O'CLOCK position. Regards Ramu
--- On Wed, 9/7/08, sachin sankhe <sachin.sankhe@rediffmail.com> wrote:
From: sachin sankhe <sachin.sankhe@rediffmail.com>
Subject: [MW:907] Re: Hardness variation on a temper bead welded F65 forging
To: materials-welding@googlegroups.com
Date: Wednesday, 9 July, 2008, 4:20 PM
Hi,
Actually as stated by me early we have first carried qualification in 5F position & later on 2F position.
I had mentioned 6 O'CLOCK & 12 O'CLOCK position for 5F position
Thanks for explaining the reason.
Regards
Sachin.Sankhe
On Tue, 08 Jul 2008 Bathula Raghuram(Mumbai - PIPING) wrote :
>It is some thing tricky, and difficult to evaluate the exact cause. Your
>assumptions regarding HI could be the reason for this at a particular
>position.
>
>But one thing is not clear to me, you welded this piece in rotating, how
>do you identify the 12'o clock position, where hardness is more?
>
>Yes your conclusions stated below will help us definitely in due course.
>
>
>
>Regarding your query on the previous statement the right vertical line
>is toe of the weld and left vertical line is toe of the surface temper
>reinforcing bead, this is mentioned to give a rough idea of surface
>temper bead placement, please note these surface temper beads may remain
>in place or may removed by grinding.
>
>
>
> The in tempered HAZ as shown with arrow. Attachment in the previous
>post shows the same for tempering this arrow marked portion.
>
>
>
>________________________________
>
> From: sachin sankhe [mailto:sachin.sankhe@rediffmail.com]
>Sent: Monday, July 07, 2008 6:59 PM
>To: materials-welding@googlegroups.com
>Cc: Bathula Raghuram (Mumbai - PIPING)
>Subject: Re: [MW:904] Hardness variation on a temper bead welded F65
>forging
>
>
>
>
>Dear Mr.Raghuram/Members,
>
>Let me apologise for not putting subject.
>
>Yes I had taken care as mentioned in your mail
>As u can see in attached figure that 8th pass was done on 6th pass.
>Distance between welding edge of 6th pass & 8th pass(i.e vertical
>distance in your mail sketch) was 3mm
>Yes preheating was done min. 150 deg.C & INTERPASS temp maintained at
>180-190 Deg.C
>
>Also why it give high hardness on 12 O'CLOCK POSITION ONLY whereas it
>was accaptale in 6 O'CLOCK position
>
>Today I could see Macro of all specimen from DNV,Lab(Singapore).I
>compared weld profile of both 6'O CLOCK & 12 O'CLOCK specimen.I have
>noticed that fusion line in 12 O'CLOCK was not straight i.e When fusion
>line deviated far into base metal at that point hardness value was too
>high.So I think welder shall try to maintain fusion line straight.
>Note that 2F position hardenss was OK
>
>So Conclusion is
>If hardness is critical to achieve
>
>1.Weld in such aposition that more Heat I/P can be done.In this case
>preferable position was 2F compare to 5F
>2.During capping avoid welding on base metal
>3.Grind 1/4th or may be 1/2 of last fill passes before doing capping so
>that we can get good tempering of last fill pass
>4.Last Capping pass(Temper bead technique) shall be not that close to
>base metal so that it makes its own untempered HAZ in base metal
>
>Views on above concluded points are welcome
>
>I was not clear on your below statement can u be bit more clear on this
>
>"The distance between two vertical lines (as shown in attached sketch)
>shall be small enough that HAZ of reinforcing bead tempers all of the
>unaffected HAZ in the base metal, but not so small that it creates its
>own untempered region."
>
>Regards
>Sachin.Sankhe
>
>
>
>
>On Mon, 07 Jul 2008 Bathula Raghuram(Mumbai - PIPING) wrote :
> >Dear members
> >
> >Request to use appropriate subject line, thou the topic was very
> >interesting to discuss, it may be ignored by many in absence of an
> >appropriate subject line.
> >
> >
> >
> >There are chances that toe of the weld, where no tempering of HAZ has
> >occurred, in addition there is weld metal that is also not tempered, it
> >may be necessary to add a layer on top of the completed weld and grind
> >it off to get the desired results. This results in tempering of the
> >remaining untempered weld and HAZ. But be careful not to let this extra
> >tempering layer penetrates to base metal, if it, then you may create a
> >new untempered HAZ.
> >
> >The distance between two vertical lines (as shown in attached sketch)
> >shall be small enough that HAZ of reinforcing bead tempers all of the
> >unaffected HAZ in the base metal, but not so small that it creates its
> >own untempered region.
> >
> >(Remember) Cooling rate during welding : Thicker one cool faster than
> >thinner ones, with lower heat input cool rapidly than higher heat
>input,
> >cooler base material cool quicker than hotter ones (did you preheat
>this
> >one?)
> >
> >
> >
> >
> >
> >Invite more discussions, and active participation, irrespective of your
> >views whether right or wrong as only in discussion we can improve
> >
> >________________________________
> >
> > From: materials-welding@googlegroups.com
> >[mailto:materials-welding@googlegroups.com] On Behalf Of sachin sankhe
> >Sent: Saturday, July 05, 2008 6:52 PM
> >To: materials-welding@googlegroups.com
> >Subject:
> >
> >Dear Friends,
> >
> >Recently we have come across welding situation as mentioned below
> >
> >Details are as follows-
> >
> >1.Material used -API 5L X65 TO A694 F65
> >2.Position-5F
> >3.Welding Process-GTAW(Root,Hot)/SMAW(Fill, Cap)
> >4.Welding consumable-GTAW(ESAB OK 13.09),SMAW(E8016 GH4R)
> >5.Welding Technique-Temper Bead Technique
> >6Reference Codes-API1104/NACE MR0175/DNV 0S F101
> >7.Hardness Requiremnt as per Client Spec-248 HV10
> >8.Size(12" O.D X 27.3 mm Thk to 2" O.D X 8.7 mm Thk)
> >
> >Situation-
> >1.We carried out welding procedure qualification and sent for testing
> >2.Testing to be carried out-NICK BREAK & HARDNESS
> >3.Hardness on capping pass (12 O'CLOCK )at forging side found above
>250
> >HV10
> >4.However at 6 O'CLOCK it was below 248HV10 & hence acceptable
> >5.Due to failure at 12 O'CLOCK POSITION,we decided to re-qualify.
> >6.This time we maintained high heat input(1.6-2.0 kJ/MM) on caping pass
> >at forging side
> >7.Hardness result again we found high at same location as
> >previous,however on 6 O'CLOCK position it was less then 248 HV10
> >8.Due to failure we decided along with client following option
> > a)Two procedure to be qualified one in 5F position like prevoiusly
>but
> >this time we decided to rotate the pipe when welding capping pass on
> >forging side i.e Welding to be carried out only b/w 9-6-3 o'CLOCK
> >POSITION only.Thus avoiding welding in 12 O'CLOCK POSITION
> >Also we decided to use even higher heat i/p by using larger dia.
> >electrode (3.2 mm)in place of previoiuly used 2.5 mm electrode
> > b)Secound procedure we decided to do in 2F position and maintaining
> >higher heat i/p(1.8-2.5 kj/mm)on capping pass(Forging side)
> >
> >9.After hardness testing for 5F position results on 12 O'CLOCK position
> >forging side again failed
> >10.However in 2F position it was satisfactory with same heat i/p as
>that
> >in 5F position
> >
> >Would like to know the reason of such behaviour
> >
> >Sachin.Sankhe
> >Engineer-Inspection
> >Aker Kvaerner-Malaysia
> >Mobile:012-2896901
> >Email1:Sachin.Sankhe@akerkvaerner.com
> >Email2:Sachin.sankhe@rediffmail.com
>
>
>
>
>
>
>
>
>
>>
Sachin.Sankhe Engineer-Inspection Aker Kvaerner-Malaysia Mobile:012-2896901 Email1:Sachin.Sankhe@akerkvaerner.com Email2:Sachin.sankhe@rediffmail.com |
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