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Re: 04 - Re: [MW:6711] Reg Range of Amperage in WPS

By Materials & Welding
Hi Muhammed,
 
If in the PQR the amperage value ( min is 350 & max is 550 ),
 
then you have to do is ( 350 + 550 ) / 2 = 450. Then your max variation could be 450 ( + or - 10 % ) i.e 405 Amps ( Min ) to 495 Amps( Max ).
 
Reason is ,
 
1. Generally WPS is to be extracted from PQR , since the weld performed with the variables specified in a PQR is mechanically tested and found to match the properties ( parent material property )
 
It means that you confirm ,  if a welding is performed within the limit specified in a PQR then the weld would surely achieve the parent material property.
 
So when you cross that boundary ( Example : 550 + 10 % i.e 605 Amps ) , then you have no proof to say that the weldment still have the same property.
 
But when you specify it within PQR limits i.e 405 Amps to 495 Amps , you have a solid evidence that the weldment has met the parent material property through your PQR - mechanical testing results.
 
Hence your Case 2 would be the right answer.
 
Note : Hope the amperage provided by yourself is a rough example , since for no material the min and max amps would vary around 200 amps. Usually the maximum variation would be 50 amps. i.e PQR - Min 200 Amps to Max 250 Amps.
 
 
Thanks & Rgds,
 
K.Sankaranarayanan.
Hp.No : + 65 9172 6444.
 

From: Muhammed Ibrahim PK <ibratech@gmail.com>
To: materials-welding@googlegroups.com
Sent: Wed, 25 August, 2010 11:00:07 PM
Subject: 04 - Re: [MW:6708] Reg Range of Amperage in WPS

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