The channel through the lining used to drain liquid metal or slag. On a blast furnace it is drilled open for each cast and plugged afterward with taphole clay pushed in by a mud gun, and keeping a long, stable taphole protects the hearth. Electric arc furnaces with eccentric bottom tapping fill the taphole with sand between heats.
Heard on the job
Taphole length is down to two metres on the east hole, change the clay and slow the drilling.
Also heard as
- tap hole
- iron notch
- tapping hole
Related terms
Mud
Shop word for the clay used to plug a blast furnace taphole, and bricklayers' word for mortar.
Elephant foot
Blast furnace hearth wear profile where the wall-to-floor corner erodes into the shape of an elephant's foot.
Salamander
Pool or mass of iron left in a blast furnace hearth below the taphole, tapped or dug out at a reline.