Sunday, March 6, 2011

Re: [MW:10176] Query for WPS & PQR of weld overlay


Additional to requirements as suggested by experts ,you may take care for  ;
  • Each layer of alloy shall be tested for iron concentration in such a manner as to obtain the
profile characteristics of iron pick-up. This inspection shall be done progressively with the work. Locations shall be
chosen at random by the Inspector
  • Iron concentration in the upper 1.6 mm of the nickel (or Monel,depending on filler ) first layer shall be less than
    25 percent with an average of less than 15 percent. Iron concentration in the upper 1.5 mm
    of the Monel layer shall be less than 5 percent at any point.
  • If iron concentrations above these are recorded, a further layer of the overlay is required
  • Each layer of overlay shall be dye penetrant inspected before proceeding with the following
    pass. All dye penetrant and developer must be removed before further welding.
  • The weld overlay shall be free of laps, lack of penetration, fissures, undercutting, slag
    inclusions, cracks or other weld defects. Micro fissures not exceeding 0.8 mm in diameter
    shall be permitted provided they are not linearly disposed. The minimum distance between
    such permitted defects in line shall be 4.8 mm
  • Shielding gas shall be welding grade argon with 99.999 purity
  • A curved sweep gauge shall be used on each overlay pass. A 1.6 mm maximum gap is
    allowed on an arc length of 0.125 x inside diameter. If the gap is greater, additional beads
    of the pass in question shall be laid in the depressions
  • Maximum hardness of all welds – 200 Brinell hardness number
Will be happy ,if you share the  results at your end.

regards

yogeshk.



On Sun, Mar 6, 2011 at 10:41 AM, Muhammed Ibrahim PK <ibratech@gmail.com> wrote:

i have a query whether i have to prepare two different WPS ( for 1.nozzle pipe to flange & 2. weld overlay inside the nozzle) --- You can use any existing butt welding procedure for butt welding and you have to make a seperate PQR for overlay.

What type of procedure i should follow?  Arrange a plate for overlay PQR with the same thickness or lower as in production. Deposit  required thickness of weld metal and carry out Penetrant test. Carry out 4 side bend and chemical analysis at minimum required depth from surface. Carry out hardness test  and macro examination if necessery.

Nozzle pipe is having Sch 80 thickness & thickness of weld overlay of monel is 5 mm.

What type of NDT i should do to check the integrity of weld overlay. --- PT

what type of special techniques required in the above mentioned job. --- Take care when depositing first layer. Reduce current as low as possible at first layer. Ensure an overlap of 40 - 50 % on each bead. Take care the inter pass temperature up to 150 deg.C and distortion of plate. Keep away from carbon steel work location, because chips and powder from carbon steel will give wrong chemical result. Do not use carbon steel wire brush and grinding wheel.

Thanks & Regards
Muhammed Ibrahim PK



On 4 March 2011 09:58, Manindra Singh <hellmanya@in.com> wrote:


Dear friends,

I want to prepare WPS & PQR for weld overlay of Monel inside the NB 6" nozzle (material SA 106 Gr B, length 8-10").

i have a query whether i have to prepare two different WPS ( for 1.nozzle pipe to flange & 2. weld overlay inside the nozzle) --- You can use any existing butt welding procedure for butt welding and you have to make a seperate PQR for overlay.

What type of procedure i should follow?  Arrange a plate for overlay PQR with the same thickness or lower as in production. Deposit  required thickness of weld metal and carry out Penetrant test. Carry out 4 side bend and chemical analysis at minimum required depth from surface. Carry out hardness test  and macro examination if necessery.

Nozzle pipe is having Sch 80 thickness & thickness of weld overlay of monel is 5 mm.

What type of NDT i should do to check the integrity of weld overlay. --- PT

what type of special techniques required in the above mentioned job. --- Take care when depositing first layer. Reduce current as low as possible at first layer. Ensure an overlap of 40 - 50 % on each bead. Take care the inter pass temperature up to 150 deg.C and distortion of plate. Keep away from carbon steel work location, because chips and powder from carbon steel will give wrong chemical result. Do not use carbon steel wire brush and grinding wheel.

Thanks & regards

M P Singh

Inspection Engineer



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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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