The tunnel kiln body adopts a segmented floating structure, which can effectively prevent the influence of unfavorable factors such as kiln body deformation caused by thermal expansion or subsidence of the foundation during use. It has a solid metal frame, and the kiln wall is fully enclosed and welded with steel plates. The use of perfect thermal insulation materials ensures that the firing temperature of the tunnel kiln can reach 1350 ℃ and high temperature impact resistance, so that the kiln has the longest service life. Heavy clay bricks are used below the curved seal of the whole kiln, and light clay bricks and high alumina bricks are used in the rest of the preheating area. The high temperature area adopts mullite brick with good thermal insulation performance and good thermal shock resistance. The quenching area is equipped with a rapid cooling device, which is controlled by frequency conversion to make the temperature quenching control precise. The appearance is made of decorative board, which is beautiful and elegant, and can be insulated and cooled at the same time.