-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of UR Rao
Sent: Thursday, February 28, 2008 6:06 PM
To: Materials & Welding
Subject: [MW:623] Re: 596] Re: selection of Production test coupons (PTC)
Mr. Jivan, i would like to throw some light on this topic. (my
explanation is not code requirement however it is part of engineering
which will help you is understanding you surveyors requirement).
your BV surveyors intention in asking you to do the mechanical test
for PTC#1 and PTC#2 was right, however he could not put the request
properly.
you are purely looking in to the code requirement and arguing the case
however what you forgot was the metallurgy and mechanical properties
of materials.
the material you were using to build your sphere was SA 537 Cl 2 whose
tensile strength is 80 - 100 ksi.
you are intended to subject the bottom part of sphere to two PWHT
Cycles.
when you compile your data, the base material you are using is 80 -
100 ksi and electrode you are using is 80ksi.
please carefully read the manufacturers data supplied of your welding
electrode manufacturer, you will see that the results posted were as
welded not after one PWHT or 2 PWHT Cycles.
the reason why manufacturer publishes only as welded results was,
because you will get higher mechanical properties in as welded
condition than what you will get after one PWHT cycle.
when you do second PWHT cycle you will end-up with further low
mechanical values than 80 ksi.
please check with your electrode manufacturer and ask him to conform
the strength of electrodes will meet SA 537 Cl 2 tensile requirements
(he will definitely will not do that).
in my opinion, so as a guarantier of sphere manufacturing, you have a
reconcilability to supply agreed product to your end user, hence you
shall subject your weld procedure to both one cycle and two cycles and
then test the coupon for its mechanical and impact properties.
On Feb 28, 6:50 am, "Bathula Raghuram \(Mumbai - PIPING\)"
<R.Bath...@ticb.com> wrote:
> What is your welding position of PTC #1? Assuming you are using Same WPS
> for all joints (category A, assuming all your welds fall under this
> category) and you have done your PTC#1 in Vertical position, In my
> opinion PTC#2 is not required {refer UG-84(i)(3)(a)(2)}.
>
> However it could be the reason your Surveyor is asking for PTC#2, since
> some portion weld seam is subjected to PWHT two times, in that case even
> your PTC#2 should undergo PWHT twice, is n't it? I am not clear on this;
> members please share your views?
>
> ________________________________
>
> From: materials-welding@googlegroups.com
> [mailto:materials-welding@googlegroups.com] On Behalf Of Jivan Dhamane
> Sent: Friday, February 22, 2008 4:13 PM
> To: materials-welding@googlegroups.com
> Subject: [MW:596] Re: selction of Production test coupons (PTC)
>
> Dear Friend
>
> Design code is ASME Section Div.-1. MOC is SA 537 Cl.2, Thickness is
> 57.5mm to 59.9mm, MDMT is -46 (Minus) Degree Celcius, Welding Process is
> SMAW, Filler metal AWS clasification E8016-C1, PTC thickness is 59.1mm,
> PWHT Cycle is Heating rate above 426 Degree celcius -94 Degree per hour
> max., Soaking Temp.-586-606 Degree, Soaking Period 2 hours 30 Minutes,
> Cooling rate above 426 Degree celcius -117 Degree per hour max.
>
> Hope I clearify ur queries.
>
> Regards
>
> Jivan Dhamane
>
> Raghuram Bathula <raghurambath...@gmail.com> wrote:
>
> can please explain more about your problem, Design code, MOC,
> Thickness involved, MDMT , Welding process used...
>
> On Feb 19, 2008 5:57 PM, Jivan Dhamane
>
> <jivanadham...@yahoo.co.in> wrote:
>
> Dear Friends
>
> I have two queries that are as follows please advice me.
>
> 1. We are constructing Horton Sphere, at the initial stage
> our subcontractor had submitted PWHT procedure for whole sphere, but due
> to some accessories to inserted in the sphere for PWHT purpose they
> revised PWHT procedure in two parts. That is by Internal Firing Method
> for whole sphere except (Bottom Centre Crown plate weld) and after
> welding of Bottom Centre Crown plate weld PWHT is to carry out by Local
> Electrical Heating Method.
>
> By doing so, BVIS Surveyor is asking for 02 Nos. Production Test
> Coupons (PTC). One for PWHT by Internal Firing Method and another for
> PWHT by Local Electrical Heating Method. We tried to convince BVIS
> Surveyor for only one no. PTC as Welding Procedure Specification (WPS),
> PWHT cycle and other all construction activities are same for both the
> part but BVIS Surveyor is no satisfied and asking for 02 Nos. PTC.
>
> Waiting for your reply, till then take care and good bye
>
> Regards
>
> Jivan Dhamane
>
> ________________________________
>
> ________________________________
>
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