Re: [MW:16391] Vacuum Packed LH Electrodes

Mr. Abhisekh,

" After opening packet at the start of the days work , is it necessary to transfer a pack of  electrodes to a portable quiver for holding 

at temp 100 deg C to prevent further moisture pick up ? or it is not required as manufacturer says that after opening up to 9 hrs it can be used at 80% / 27 deg C .

Electrodes rebaking cycle depends upon which factors? Some client specifies recycling 1 time  , some 2 times ... [ As per BIS 13851:1993 , ( R 2006) - Storage & redrying of coverd electrodes  before use recommendations- 3 times ] "

Answer:

The very purpose of using  E 7018-1 H4 type Vacuum packed Electrodes is to avoid re-backing, as the H2 level is 

<4 ml /100 grams of weld and can be used straight after opening the pack. 

When not used  after  breaking the seal and considerable gap of time, re-baking is to be done, as the electrodes would 

have picked up  moisture by then, due to its exposure to humid conditions.

Without H-4 designation, all low Hydrogen type electrodes may have > 10 ml  & < 15 ml of H2 per 100 grams of weld and compulsory re-drying has to be done to reduce the H2 content to <10 ml. by holding them at 300 deg. C for 2 hrs 

in the ovens.

The electrodes are held in Holding oven (if required) at 100-150 deg.C,  if backed in large quantity and to avoid repeated 

re-baking (re-cycling) and damage to flux coating if unused.

Welders are supposed to use portable (kept at 100 deg. C or so) for actual welding. These ovens also know as re-fill ovens

as the electrodes are refilled after every 2 hrs welding work or less.  

Sridhar.

---

From: ABHISHEK GHOSH <ghoshabhishekmech@gmail.com>
To: materials-welding@googlegroups.com
Sent: Sunday, 30 December 2012 11:17 AM
Subject: [MW:16383] Vacuum Packed LH Electrodes

Dear Experts, 

We are using E 7018-1 H4 Vacuum packed Electrodes for our project. ( Refer attachments ) , where manufacturer recommendations is mentioned as : 

HD [ ml/100g] : at opening time : <5 

Working time after opening : 9h at 80% RH / 27 deg C 

After this period rebaking : 2h/340-360 deg C 

Brand : Supercito VP Medium ,Oerlikon , Air Liquide Wedling France. 

Weather Condition at site : 78- 80 % Humidity , Temp 26-30 Deg C. 

My question is :

 After opening packet at the start of the days work , is it necessary to transfer a pack of  electrodes to a portable quiver for holding at temp 100 deg C to prevent further moisture pick up ? or it is not required as manufacturer says that after opening up to 9 hrs it can be used at 80% / 27 deg C . 

• Electrodes re-baking cycle depends upon which factors? Some client specifies recycling 1 time  , some 2 times ... [ As per BIS 13851:1993 , ( R 2006) - Storage & redrying of coverd electrodes  before use recommendations- 3 times ] 

Please clarify . 

Thanks & regards. 

Abhishek Ghosh 

Indonesia 

Linkedin: id.linkedin.com/pub/abhishek-ghosh/15/899/271

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