Application

ELECTRODE ASSEMBLY

USEING IN ARC FURNACES

1 Preparations for adding electrodes

Remove the end cover and blow out the threaded socket with dry, oil-free compressed
air.Do not clean the threads with steel wool or wire brushes.

2 Adding the nipple.

The nipple must be inserted in the socket without applying pressure or tilting, then
tightened by hand.

3 Joining the new electrode

Clean the end face and socket of the electrode column with oil-free compressed air,
screw in the new electrode, at first by hand or with a clamping ring, and then tighten
to the specified torque.

Torque for the joining of graphite electrodes.

Electrode Dia (mm)	75	100	130	150	175	200	225	250	300	350
Torque (Nm)	30	50	90	130	200	250	350	450	650	850
Electrode Dia (mm)	400		450		500		550		600
Torque (Nm)	1000-1100		1300-1500		1800-2000		2200-2400		3000-3200

The specified torque can be applied manually (with a torque wrench) or mechanically.

4 Imperfect joint

----Non-uniform mechanical stress due to asymmetrical position of nipple thread,
possible consequences:

I ＭＰＥＲＦＥＣＴ
　　ＪＯＩＮＴ

ＰＥＲＦＥＣＴ
ＪＯＩＮＴ

ＧＯＯＤ　ＣＵＲＲＥＮＴ
ＴＲＡＮＳＦＥＲ－
ＮＯ　ＴＨＥＲＭＡＬ
ＶＥＲＬＯＡＤＩＮＧ

ＴＯＲＱＵＥ
ＴＯＯ　ＬＯＷ

---Cracking
---Stub-end/butt losses
---Electrode breakages,
---Poor current transfer---thermal overloading, possible consequences:
---Overheating of the nipple.
---Increasing electrical resistance (higher power losses)
---Higher oxidation rate at the joint
---Greater risk of breakage.

5 Perfect joint

----Uniform mechanical stress due to symmetrical position of nipple
---Good current transfer no thermal overloading.