Annealing And Cooling Of Sanitary Stainless Steel Elbows
Annealing cooling of Sanitary Valve:
The sanitary stainless steel elbow annealing furnace is a horizontal suspension type continuous annealing furnace, which mainly uses natural gas as fuel. To maximize the work efficiency, a continuous tunnel type is selected. The heat treatment section is divided into a preheating zone, an open flame heating zone, a water-cooled initial cooling zone, a water-cooled final cooling zone, and a monotonic section. The lengths of each section are: 40m, 4×15m, 3×5m, 3×5m, and 1×5m. The supporting roller is also included, with a total length of about 155m. When treating austenitic stainless steel elbows, the technical section speed is 80 meters per minute. The following will take austenitic sanitary stainless steel elbow pipe fittings as an example to explain the characteristics of each section:
The preheating section uses the calming gas of the direct-fired heating section to preheat the strip to about 400°C before entering the direct-fired heating section, and is equipped with a heat recovery device. A variable frequency speed regulating fan with an air volume of 107530Nm3/h is used to discharge the furnace gas to ensure the furnace pressure and stop heat recovery.
The heating section is divided into four sections of direct combustion, each section is equipped with thirty nozzles, a total of one hundred and twenty, the annealing temperature is 1100℃, the maximum temperature of the furnace heat storage body can reach 1250℃, and the preheating section and each heating section are equipped with oxygen content meters and thermocouples. Disc roller support assemblies are installed between different furnace sections, a total of five, which are willing to change rollers online quickly. Each disc roller assembly is equipped with two ceramic fiber support rollers.
The primary cooling and final cooling zones each have three sections of water spray quenching, and the water spray system adopts a special design. Each of the three sections of the primary cooling zone includes ten sets of nozzles on the upper and lower sides of the plate and strip, each nozzle is equipped with four nozzles, and each nozzle is equipped with a manual adjustment valve and a pressure gauge. When the temperature of the plate and strip drops from 1100℃ to about 500℃ after passing through the primary cooling section, the final cooling zone includes three cooling boxes of the cooling section. Each cooling section is equipped with 11 sets of AISI304 stainless steel water spray pipes, each with eight nozzles. The nozzles of adjacent water spray pipes are staggered to ensure uniform water spray. After passing through the final cooling section, the temperature of the strip usually drops below 80°C. The drying section includes squeeze rollers, air blowing and eight sets of hot air nozzles to dry the surface of the steel strip.
