Storage and Handling of Electrodes [Part 2]

What is the procedure for baking of electrodes?

The electrodes are removed from their original packets(hermetically sealed containers will discussed later) and are put in the trays in the mother oven at a temperature not exceeding one half the final baking temperature for a minimum of one half hour prior to increasing the oven temperature to the final baking temperature. The temperature is set in the automatic temperature controller. When the set temperature is reached it will be allowed to remain at that temperature(baking temperature) as per manufacturer recommendation/as per standard/code/procedure requirement. When the time is completed it will be transferred to the holding/storage oven, where a constant temperature is maintained. Electrodes as required for the job will e transferred to the portable oven from the holding oven.

The baking temperature will be as per manufacturer recommendation. As per AWS D1.1, Clause 5.3.2.4,
1. All electrodes having low-hydrogen coverings conforming to AWS A5.1 shall be baked for at least two hours between 260 Deg C and 430 Deg C

2. All electrodes having low-hydrogen coverings conforming to AWS A5.5 shall be baked for at least one hour at temperature between 370 Deg C and 430 Deg C

As per AWS D1.1, Clause 5.3.2.1, the holding oven temperature shall be maintained at a minimum temperature of 120Deg C.

PORTABLE OVEN

How the electrodes are arranged in an mother/portable oven?

The most common design of mother/portable oven consists of heating coil at the bottom and 3 or 4 grilled racks at the top of it. The electrodes are to be placed in each rack such that the hot air will move to the next rack above it. Normally 2 to 3 layer of electrode is placed in a rack which will give a uniformity in heating.

The entire oven can be placed with same electrode of different sizes or each rack can be used for different electrodes. 

Though filling different racks with different type of electrodes is the most preferable method, there is risk of mixing of electrodes. 

It can happen in the following ways.

1. There are chances that the electrode may accidentally fall from one rack to the another while filling/issuing the electrodes. This will cause mixing of electrodes.

2. While filling the electrodes there are chances that the electrodes are wrongly filled in a rack.

Who should issue the electrodes?

Electrodes are to be issued by a experienced store keeper/person (Electrode Issuer). No body is allowed to enter to the electrode issuing area for taking the electrodes by their own other than the electrode issuer.

There should be an engineer/supervisor responsible for electrode handling process and he should monitor the process of electrode issuer and corrections/directions to be issued by time to time

What is the experience required for an electrode issuer?

He should have the basic knowledge of English for reading and writing. He should know the electrode names, brand, baking procedure and electrode issue procedure.

What are the Duties of an electrode issuer/electrode store keeper?

1. Maintain and update the stock records of electrode.

2. Maintain the correct backing procedure.

3. Maintain the baking register. 

4. Issue of electrodes based on the electrode slip approved by welding engineer.

5. Liaison with the engineer/supervisor in-charge of the electrode handling process for stocks, discrepancy happened if any, damages in electrode if any etc.

6. Maintain the mother oven and portable oven in good condition

7. Calibration of ovens before due dates and maintain a valid calibration certificate.

8. Replenish the electrodes in the ovens as per work load and in communication with welding engineer.

9. Electrode mix if happened to be brought to the knowledge of welding engineer.

10. If power has gone during baking re-baking to be done in consultation with the engineer/supervisor in charge for electrode handling process.