L-shaped anchor nails. L-shaped nails are mostly used in the top of the furnace, and are suitable for single-layer furnace insulation structure. Due to the particularity of the top of the furnace, during the construction of the furnace roof, the thickness of each construction is 40-50mm, then the steel wire is wrapped around the construction thickness, fixed on the L-shaped anchoring nail, and then fixed on the L-shaped anchoring nail with the card. In the small groove, the card can prevent the steel wire from sliding down and play the role of fixing the refractory castable, which not only improves the integrity of the refractory castable, but also increases its thermal shock resistance and plays a good use effect. Anchors are mainly used for spray coating of amorphous materials. Therefore, when manufacturing L-shaped anchor nails, it is necessary to pre-open a small groove every 50 mm or so.