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-----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.
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
Sanjay
JsonsSent 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
--- 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
PREM S NAUTIYAL
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
>
>>
CELL : 9820313278
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