Steel car and Slag car are moved using Cable Reeling Drum (CRD) composite cables. The temperature near the vicinity of CRD composite cable is > 1600 °C. Steel car is used for carrying liquid steel from tapping zone to ladle lifting zone. Liquid steel is tapped in the ladle kept on the Steel car after oxygen blow and ferroalloy addition. While liquid steel is being tapped, CRD composite cable gets damaged due to liquid metal spatters. This prevents the movement of the Steel car, which leads to stoppage of the Converter.
Liquid slag left in the ladle after tapping is poured in the Slag car which is taken to the Slag Pot Lifting Zone. While liquid slag is being poured in the Slag pot kept on the Slag car, here also, the CRD composite cable gets damaged due to spatters, stopping the movement of the Slag car which leads to stoppage of the Converter. In both the cases, the spattered liquid metal reacts with the cable insulation and starts to build up on the cable, this leads to weakening of the cable and eventually to its breakage.
To mitigate the problem following options have been tried:
- Heat shield has been extended on Steel car and Slag car side in both the Converters. This has prevented the spatters from falling directly on the cable.
- Heat resistant tape has been applied over CRD cable to avoid the cable damage from metal spatter. This has reduced the frequency and severity of the cable damage.
- Heat resistant curtain was tried but it got damaged due to the heat.
- Motor protection cover locking arrangement, was made to prevent the metal from falling on the motor and cables. This has helped in preventing the spatter from falling on the cable.
- Levelling mismatch of Hose Reeling Drum (HRD) and CRD has been rectified to avoid physical damage to insulation of the cable.
- The damaged Teflon rollers of the CRD have been replaced with new rollers to avoid physical damage to the insulation of the cable.
We are seeking a solution that will prevent the damage of CRD composite cables due to liquid metal spattering.
The solution MUST meet the following criteria:
- Zero damage of cable in any Steel car/Slag car.
- Should not necessitate substantial changes in the existing setup.
- Should not hinder existing operations.
- It should prevent the Lance jam from falling onto Steel car or on track during tapping.
It will be an added advantage if the solution addresses the following:
- Commissioning of Slag Retaining Device (SRD) for closing the tap hole immediately after tapping to reduce the metal spatter.
- Converter mouth cleaning on regular basis to avoid the metal falling in vicinity of the CRD cable.
- Regular track cleaning to avoid jamming of Steel car.