A common practice in steel mills is the reheating of slabs or billets in furnaces wherein temperatures exceed 2,000.degree. F. These slabs or billets move along raised rail-like extensions of hollow pipe members. Cooling water is circulated through the pipes to prevent fusing of the slab material and the rail-like extension. The cooling pipes are commonly sheathed with refractory material to prevent cooling the entire furnace below efficient operating levels.
The refractory material used to sheath the cooling pipes must be extremely durable to withstand an intense heating environment. Massive slabs moving along the protruding rails cause vibration which can induce deterioration of the refractory material. Thus, the combination of alternating steep thermal gradients accompanied by intense vibrations requires a very stable sheathing.
In the past, securing means such as lugs and tabs welded to the cooling members have been necessary to enable the refractory material to withstand the vibration induced trauma. However, the repair or replacement of the refractory material requires a labor-intensive time consuming process. The old material had to be removed as well as hot-rodding off the old stainless steel welds. Then new pieces must be tied in place and welded. Finally, masons must plaster over the welds to protect from heat and increase the useful life of the welds.
There have been some improvements reducing the amount of labor in applying refractory material. One such improvement is a refractory tile of a C-shaped block with a hollow side to engage the cooling member. This block has an upper end engaging over the cooling member with a lower end that swings under gravity and engages underneath the member with a complimentary tile. Problems with this design still persist in that refractory mortar must be used in the gaps between the skid rail and the upper end of the refractory tile. This requires that the slab be removed from the furnace anytime repairs or replacements are attempted. The two piece design engaging beneath the support member is prone to separation caused by intense vibration. The introduction of slag between the engaging tiles will facilitate such separation and all thermal advantages will be lost. The block is not economically feasible because the heat loss is less expensive than the cost of production and for this reason is not extensively used.
The present invention provides a refractory tile that can be introduced or repaired on a cooling member without the removal of the slab. This is an extreme advantage in the amount of energy that is likely to be needed to bring the slab and furnace up to rolling temperature. The repair time will be reduced resulting in less down time of operations.