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[MW:1207] RE: 1206] Re: Process required to repair crack in casting ASTM A148GR 80-40

By Materials & Welding 
The following general practices have been found to be useful in the welding process:
  • When no preheat is used, the interpass temperature should not exceed 95 °C (200 °F)
  • When preheat is used, the interpass temperature should not exceed the preheat temperature by more than 40 °C (100 °F)
  • To minimize welding stresses, a backstep sequence should be used with stringer beads no more than 50 to 75 mm (2 to 3 in.) in length; each deposit should be allowed to cool to approximately 40 °C (100 °F)
  • before making subsequent deposits
  • Avoid melting more of the casting than is necessary
  • Whenever possible, deposit two or more layers for best machinability
  • Always strike the arc in the weld groove, never on the casting
  • The arc length should be kept as short as possible, typically 3 to 5 mm
-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com]On Behalf Of western.precicast@gmail.com
Sent: Tuesday, October 14, 2008 9:25 AM
To: materials-welding@googlegroups.com
Subject: [MW:1206] Re: Process required to repair crack in casting ASTM A148GR 80-40

Before starting the welding , in addion to the suggestions in the emails , if hardness at the defective area is controlled to 260 BHN or below the chances of cracks will be very low. If hardness is more than 260 BHN. , tempering is advised.

Sanjay
Jsons

Sent from BlackBerry on Airtel

From: gopal sankar <gopalsankar@yahoo.com>
Date: Tue, 14 Oct 2008 00:08:52 -0700 (PDT)
To: <materials-welding@googlegroups.com>
Subject: [MW:1205] Re: Process required to repair crack in casting ASTM A 148 GR 80-40

Preheat temperature seems to be on lower side.If it is more than 400 Deg.C the chances of crack reappearing can be avoided.
 
regards,
gopalsankar
Head-Inspection
SVL Engineering Services
Chennai

--- On Mon, 10/13/08, PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com> wrote:
From: PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com>
Subject: [MW:1203] Re: Process required to repair crack in casting ASTM A 148 GR 80-40
To: materials-welding@googlegroups.com
Cc: "greetings" <senthilthandesh@gmail.com>
Date: Monday, October 13, 2008, 9:11 PM


Dear Friend

ASTM A 148 is a ferritic-pearlitic carbon steel for cast products. It is used for higher pressures and stress parts like crane wheels,etc..
I think the chemical composition is C=0.4-0.5, Mn=0.4-0.8, Si=0.2-0.5,P&S=max.0.090.

First you should arrest the crack by drilling two holes,remove the crack by hand grinding, ensure crack removal by LPT.
Preheat the job to 250 degrees celcius, Use E7018-1 electrodes,Interpass temp of 250 degrees celcius and weld. After welding cover the job with asbestos cloth for slow cooling.
I am suggesting you this procedure because we had repaired one cast steel of similar composition in the past.

Any suggestions / expert comments are welcome...

Cheers

Prem Nautiyal
Godrej, Mumbai
Cell: 9820313278

On Sun, 12 Oct 2008 greetings wrote :
>Friends,
>            Crack observed in casting material ASTM A 148 GR 80-40
>Can any one give the process to rectify the crack (welding electrode,Preheat
>Temp & etc)
>
>Regards
>DST
>
>>
PREM S NAUTIYAL
CELL : 9820313278





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