Electrode Classification as per AWS A 5.1



      Electrode Classification as per AWS A 5.1

                                     In the process of manufacturing the welding is main process in fabrication. The Electrode required for welding is also plays major role in the quality of welding. As per the material and other requirement the electrodes are used with different sizes and different grades of electrodes are being used as the type of fabrication work.

         The electrodes classification is done on the basis of different parameters such as chemical properties strength etc, Let we discuss the classification of electrodes as per AWS A5.1 .

1)   The prefix “E” indicates Arc welding electrodes.

2)    Out of four numbers mentioned on electrodes the first two numbers & Five numbers of electrodes the first three numbers indicates the minimum requirement of tensile strength.

For example,

1)   E-60XX : Indicates the minimum tensile strength 60,000 PSI.

2)   E-70XX : Indicates the minimum  tensile strength 70,000 PSI.

3)   E-80XX : Indicates the minimum tensile strength 80,000 PSI, and so on.

3)   The Third digit in four numbers and Fourth digit in five digits mentioned on electrode is indicates welding position by which welding is done.

If the number on that place is 1 it means Welding prefer for all position.

If the number on that place is 2 it means that Welding prefer for Flat position and horizontal fillets.

4)   The last two digits indicated the coating type, polarity and current requirements. The following digits shown the type and requirements as shown,

1)   10 : 10 number means the electrode suitable for all types of welding positions the coating contein cellulose.

2)   11 : The number 11 is similar type but the difference is that specially used for only AC supply, we can also used that type of electrodes with DS supply but welding quality and weldability expense.

3)   12 : The 12 number indicates which is suitable for all type of welding positions but mainly used in flat position and horizontal position.

4)   13: The number 13 indicated used in all type of welding positions. Can be used with both supply as AC  and DC .

5)   14 : The 14 number indicates increase in efficiency, such type of electrode contain coating iron powder. Can be used with AC and DC(+) and DC(-).

6)   15 : The number 15 is shows suitable for all welding positions, can we used with DC(+) supply only.

7)   16 : The 16 number indicated similar type used with AC supply and DC(+) supply.

8)   18 : The 17 number indicated increased efficiency and can be used with AC and DC(+) supply.

  For example shown below,

 Pic01.


E7018 Electrode

9)   20 : The number 20 indicates that suitable for flat position, such type of grade contain large amount of iron oxide, can be used with AC,DC(+) and DC(-) supply.

10)                 24 : The 234 number indicates that use in flat position. Can be used with AC,DC(+) and DC(-) supply.

11)                 27 : The 27 number type grade contain acid type contact electrode. Can be used with AC and DC(-) supply.

12)                 28 : The 28 number type electrode suitable for flat position, efficiency higher than EXX18 electrode, can be used with AC and DC(-) supply.

     Proper welding procedures required following parameters,

A)  Correct Current. : If supplied current is very high or very low then its badly effect on weld of the joint.

If supplied current too high then the electrode melts fast and because of that molten pool is large and irregular shape.

If supplied current too low then there is not enough heat to melt the base metal and because of that the molten pool is too small and irregular. The change in current that is too low or too high impact on molten pool as pool is irregular.

B)   Correct length of arc. : If the voltage is too high or arc is too long then metal melts off the electrode is large that effects the poor fusion between original metal and deposited metal.

C)   Correct size of electrode : The large numbers of factors may affected by the size of electrode such as type, preparation of joint, position, the ability of electrode to carry the hight current without loss of metal and maintain the original properties after welding.

D)  Travel speed : For good welding the speed of welding required adequate as if the Speed of welfing is too high then the pool does not long enough also impurities locked in and if the speed of welding is too slow then the metal piles up and the weld bead is wide.

E)   Angle of electrode : The angle of electrode id very important in fillet welding. The angle between plates make improve quality of weld if correct electrode angle.

 

Previous
Next Post »