Dear Mr. Breaux,
In my previous e-mail I forgot to give my reaction on the second part of your reaction.
Because hydrogen cracking is caused by a combination of critical structures, increased hardness, tensile stresses and last but not least the presence of hydrogen.
Due to treatment of the separate weld runs you lower the residual stress level and because of that you will also minimize the risk of hydrogen cracking.
This kind of post weld treatment as well as stress relieve heat treatment are the only two heat treatment methods which can be replaced by this treatment. Every other PWHT is related to resolve carbides in the microstructure or normalizing the microstructure and therefore can’t be replaced by high frequency hammering.
For most of the design specifications high frequency hammering is not approved as replacement for PWHT methods but in case where PWHT is not possible or where distortion during repair welding becomes a problem notified bodies will accept this as a replacement.
Met vriendelijke groeten / Best Regards
Herman Pieper
Pieper Quality Support & Inspection
Phone: +31 (0)521 380083
Fax: +31 (0)84 7539225
Cell: +31 (0)6 51691215
www.pieper-qsi.nl
Van: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] Namens metalock@eatel.net
Verzonden: vrijdag 18 maart 2011 1:15
Aan: materials-welding@googlegroups.com
Onderwerp: Re: [MW:10407] CS to SS welding
What is the recommended frequency at which the part should be subjected to while the welding is being performed.
This process does not eliminate the need for some post weld heating to minimize the chance of hydrogen cracking.
Any info appreciated.
Thanks.
Tommy Breaux
Sent via BlackBerry by AT&T
From: "Pieper QSI" <pieper-qsi@kpnmail.nl>
Sender: materials-welding@googlegroups.com
Date: Wed, 16 Mar 2011 15:30:58 +0100
To: <materials-welding@googlegroups.com>
ReplyTo: materials-welding@googlegroups.com
Subject: RE: [MW:10388] CS to SS welding
Thanks John,
I agree with that, we have also several applications where this technology is applied in order to enhance materials and/or welds stress corrosion resistance.
Of course these technologies normally most are used in cases where fatigue is the problem you can use it for these applications as well.
Met vriendelijke groeten / Best Regards
Herman Pieper
Pieper Quality Support & Inspection
Phone: +31 (0)521 380083
Fax: +31 (0)84 7539225
Cell: +31 (0)6 51691215
www.pieper-qsi.nl
Van: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] Namens John Henning
Verzonden: woensdag 16 maart 2011 14:35
Aan: materials-welding@googlegroups.com
Onderwerp: RE: [MW:10387] CS to SS welding
Herman,
I would like to add that when I worked for Westinghouse, we developed welding procedures with peening for certain applications which were very sensitive to distortion. With the addition of peening we were able to prevent almost all distortion. I think the use of peening is overlooked as an effective means for controlling both distortion and some forms of stress corrosion cracking.
John
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Pieper QSI
Sent: Wednesday, March 16, 2011 6:59 AM
To: materials-welding@googlegroups.com
Subject: RE: [MW:10386] CS to SS welding
Dear Mr. Breaux,
Yes there are results of test programs for several international well known companies where these technology is applied during welding. I personally just finished a project where it is applied during repair welding of a heat exchanger shell. End customer was a large Norwegian Oil Company for which we had to perform a so called Mock-up in front of this treatment in order to prove this really reduces shrinkage, stresses and distortion. Test was executed together with a famous German Engineering company which was responsible for Engineering this heat exchanger. Results of the tests show 40% less shrinkage when applying this technology on every single weld run compared to the as welded condition. When looking at the distortion we have results where up to 60% less angle distortion is achieved compared to the as welded condition.
Met vriendelijke groeten / Best Regards
Herman Pieper
Pieper Quality Support & Inspection
Phone: +31 (0)521 380083
Fax: +31 (0)84 7539225
Cell: +31 (0)6 51691215
www.pieper-qsi.nl
Van: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] Namens Tommy Breaux
Verzonden: woensdag 16 maart 2011 12:30
Aan: materials-welding@googlegroups.com
Onderwerp: RE: [MW:10385] CS to SS welding
Dear Sir,
Do you have any proof that this method works besides the vendor’s claims?
Tommy Breaux, Mech. Eng.
President
Engineered Casting Repair Services, Inc. / METALOCK CORP
Office 225-791-8900
Cell 225-573-3059
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Pieper QSI
Sent: Tuesday, March 15, 2011 3:53 AM
To: materials-welding@googlegroups.com
Subject: RE: [MW:10361] CS to SS welding
Dear Praveen,
You may also apply high frequency hammering technologies like Pneumatic Impact Treatment during welding in order to control the amount of distortion.
With such technologies you can reduce distortion up to 50% when applied on every separate weld layer.
Met vriendelijke groeten / Best Regards
Herman Pieper
Pieper Quality Support & Inspection
Phone: +31 (0)521 380083
Fax: +31 (0)84 7539225
Cell: +31 (0)6 51691215
www.pieper-qsi.nl
Van: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] Namens vineet kumar
Verzonden: maandag 14 maart 2011 14:15
Aan: materials-welding@googlegroups.com
Onderwerp: Re: [MW:10341] CS to SS welding
Dear,
Distortion occurs when the Stress occurs due to Thermal Expansion or contraction exceed the Yield strength of material.
Factors affecting distortion, are:
1)Parent material properties
2)Amount of restraint
3)Joint design
4)Part fit-up
5)Welding procedure
Controls:
1) Preheating
2) Use of Stiffeners,Welding Jig & Fixtures, Flexible clamps.
3) Intermittent Welding process
You can control the distortion by keeping these points in mind .
You are recommended to use ER 309 L.
Regards,
Vineet Kumar
On Thu, Mar 10, 2011 at 4:48 PM, praveen nair <praveen_nair9894@yahoo.co.in> wrote:
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