Selection of pouring System:
There are two types of pouring system available to pour liquid iron. These two systems of automated pouring are as follows,
- Trolley type ladle pouring (Pouring car)
- Bottom pouring tundish
In this article we will not consider presspour system.
As we are considering lower bunch weight for pouring, typically bunch weight up to 100kgs maximum.
Basically if you are pouring cast iron or Sg iron is one important point for the selection of pouring system.
If you are pouring SG iron, then bottom pouring tundish is one more choice.
But if you are pouring cast iron, then ladle pouring car is better option.
Comparison between ladle trolley and bottom pouring:
If you are considering bottom pouring tundish, it is best for pouring SG iron. As there are less chances of slag inclusion.
But then, there is disadvantages like stopper rod and nozzle consumption and temperature drop while transferring metal from treatment ladle.
In trolley car, same treatment ladle can be used as pouring ladle. And there are no consumables except refractory. Chances of slag inclusion are disadvantage.
If you are pouring cast iron or grey iron, then pouring trolley is best option.
For both systems speed is same.
Bottom pouring tundish. :
Bottom pouring system is designed to pour from bottom, it has nozzle at the bottom, and stopper rod to control metal flow and stop pouring. But these stopper and nozzle are consumable and has to be changed daily.
If slag chokes, nozzle, there is plunge rod to clear slag from nozzle.
Also, stopper has to twist on nozzle when pouring is stopped more than two minutes, as there are chances of stopper rod getting weld to nozzle due temperature, hence its movement is necessary.
This twisting arrangement can be automatic, if pouring is stopped more than two minutes.
Tundish can be used for week time maximum, and then has to replace or repair refractory and use.
Normally there is spare tundish, which foundry people replace and take used tundish for repair.
Tundish is located such a way that its bottom nozzle comes 4 inches above from pouring cup.
This distance helps maintain pouring pressure.
Inoculation can be triggered with stopper lift, which starts pouring and hence simultaneous inoculation with pouring is achieved.
Ladle Pouring trolley car:
In this system, there is track and trolley car on the track, parallel to moulding line, treatment ladle after treatment and slag removal placed on trolley to pour.
There is no daily consumable in this system.
