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Temper bead welding

Temper bead welding

Postby gerdmil » Mon Dec 02, 2013 8:24 pm

Dear forum members,

Could you please explain what temper bead welding is and where is it used? Does it need a separate qualification or could I use an existing PQR that has been performed on butt weld single-V groove?

Thanks
Gerdmil
gerdmil
 
Posts: 9
Joined: Fri Jul 12, 2013 10:21 am

Re: Temper bead welding

Postby mohd » Tue Dec 03, 2013 6:04 pm

Dear one,

The basic purpose of TB (Temper bead welding) is to control the hardness at HAZ (heat affected zone) as PWHT does. TB also applies after field welding repair where PWHT after completion of repair is difficult.

The difference between the normal welding and TB welding is that TB weld bead has more overlap between two beads than normal welding hence it gives tempering effect to previously applied bead. Moreover, in normal welding we use the same heat input for entire welding but in TB the heat input changes for any layer.

How TB Works:
1. Welding heat input creates HAZ where its properties depend on cooling rate of repetitive cycle of weld beads. Fast cooling rate results in martensite formation and thus in a hard zone (hardness: 350 HV or more), instead slower cooling rate results in ferrite/pearlite microstructure (hardness: 250 HV or less).
2. So, our aim is to slow down HAZ cooling rate.
3. During TB welding any consequence layer has higher heat input than its previous slowing down the cooling rate and thus forming ferrite/pearlite microstructure for the previously established HAZ.

I have only explained the basics of temper bead, regarding code requirements you can refer ASME IX, QW-290 and QW-462.12 qualification details.

regards,
mohd
mohd
 
Posts: 74
Joined: Mon Jul 08, 2013 2:17 pm

Re: Temper bead welding

Postby gerdmil » Mon Dec 09, 2013 6:40 pm

Mohd,
Thank you very much for the very helpful reply,
Could you please let me know what shall I do with the very last pass(es) of the weld since they will have no ferrite/pearlite microstructure. Shall they be eliminated by grinding?
Thanks
Gerdmil
gerdmil
 
Posts: 9
Joined: Fri Jul 12, 2013 10:21 am

Re: Temper bead welding

Postby Smiti » Wed Apr 09, 2014 10:35 pm

mohd wrote:Dear one,

The basic purpose of TB (Temper bead welding) is to control the hardness at HAZ (heat affected zone) as PWHT does. TB also applies after field welding repair where PWHT after completion of repair is difficult.

The difference between the normal welding and TB welding is that TB weld bead has more overlap between two beads than normal welding hence it gives tempering effect to previously applied bead. Moreover, in normal welding we use the same heat input for entire welding but in TB the heat input changes for any layer.

How TB Works:
1. Welding heat input creates HAZ where its properties depend on cooling rate of repetitive cycle of weld beads. Fast cooling rate results in martensite formation and thus in a hard zone (hardness: 350 HV or more), instead slower cooling rate results in ferrite/pearlite microstructure (hardness: 250 HV or less).
2. So, our aim is to slow down HAZ cooling rate.
3. During TB welding any consequence layer has higher heat input than its previous slowing down the cooling rate and thus forming ferrite/pearlite microstructure for the previously established HAZ.

I have only explained the basics of temper bead, regarding code requirements you can refer ASME IX, QW-290 and QW-462.12 qualification details.

regards,
mohd


that is really helpful for all the beginners
Smiti
 
Posts: 4
Joined: Wed Apr 09, 2014 10:05 pm

Re: Temper bead welding

Postby Logosweld » Wed Apr 16, 2014 6:35 pm

A temper-bead welding technique has been developed to provide an alternative weld repair method in which the application of a high temperature post-weld heat treatment (PWHT) can be avoided.
Logosweld
 
Posts: 82
Joined: Thu Mar 13, 2014 10:27 am
Location: India

Re: Temper bead welding

Postby Logosweld » Wed May 07, 2014 3:58 pm

A temper-bead welding technique has been developed to provide an alternative weld repair method in which the application of a high temperature post-weld heat treatment (PWHT) can be avoided. In order to assess the integrity of temper-bead weld repairs, a series of experiments were carried out on a simulated temper-bead weld made on A516-70 steel plate
Logosweld
 
Posts: 82
Joined: Thu Mar 13, 2014 10:27 am
Location: India

Re: Temper bead welding

Postby amit mavai » Thu Apr 07, 2016 11:20 am

Dear forum members,
I have a WPS for P-no. 1 to P-no. 1 with PWHT & have another one without PWHT.
For temper bead welding shall I do new qualification, or the existing WPS could be applicable for temper bead welding?
amit mavai
 
Posts: 2
Joined: Wed Apr 06, 2016 10:36 am


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