RE: [MW:7522] reg baking

From experience – A job shop in Mexico was welding up some heavy frames for a company I was working for.  They were experiencing porosity in the welds and subsequent delayed cracking.  SMAW electrodes were E7018 and obtained in hermetically sealed cans from a “reputable” manufacturer.  The on-sight inspector witnessed the welding, electrodes were placed in holding ovens and issued to the welders in heated quarrels.  Similar electrodes (same manufacturer) were being used at other facilities without problem.  Metallographic examination revealed weld porosity and cracking characteristic of HIC.  Changing electrode manufacturer had no effect on results.  In the end, the inspector was leaving the facility with the plant manager one evening and being the last ones to leave the inspector saw the manager turn off the power to the facility.  It was discovered that every night and weekend, the manger turned off the power  including to the rod ovens.   Following this Ah Hah moment, all the rod ovens were cleaned out, new rod placed in the ovens and power to the ovens maintained around the clock.  Cracking and porosity ceased to be a problem.

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of vasu k
Sent: Tuesday, October 12, 2010 11:40 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:7515] reg baking

 

Dear Sir,

Thank you for the info...

what if the oven was switched off in the night with the remaining electrodes in it?  should i re-bake in the morning  or taking it to holding temp is sufficient?

 The reason why i am asking is ..i am getting more porosity in the joints..i just doubt whether we are handling electrodes properly or not...

pls clarify..

Regards

Vasu

On Tue, Oct 12, 2010 at 9:37 AM, Kathalingam Babu <kathalingam.qaqc@ppl.com.sg> wrote:

Vasu,

 

Pls find below as my opinion,

 

Regards,

 

K.Babu

 

----- Original Message -----

From: vasu k

To: materials-welding@googlegroups.com

Sent: Tuesday, October 12, 2010 1:18 AM

Subject: [MW:7486] reg baking

 

Dear All,

Iam new to piping. I have some basic doubts and i request you to please clarify..

1. In our fab yard, in the evening after the work is finished, the remaining electrodes(E-7018 and E-7018-1) are being kept back in the oven and the entire night the oven will be at 150 deg.
    Will it affect the coating if they r kept for that much time (the entire night)?

No

2. Do i have to do baking for those electrodes again in the morning?

 

Not Required

3. What is the max number of recycling of electrodes?

 

Re-Baking maximum of only once

4. what is the purpose of doing baking till 250 deg ?

 

Removal of Adsorbed moiture

 

doesnt the moisture will be removed if we maintain 150 deg i.e  continuously at holding temp?

Mfg has to advise

Regards,

vasu.

 

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.

 

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.