Heat Treatment Process and Procedures for Weathering Steel

Weather-resistant steel plates maintain a crucial market presence throughout their manufacturing process and are a vital part of the production process. This is due to the critical role weather-resistant plates play during manufacturing, making the production procedures highly refined. During production, a step involves heating, which itself is a process with numerous stages. The heating must be conducted in segments, with each segment maintaining a fixed temperature above a certain threshold, without exceeding or falling below the specified temperature standards. The degree of maturity must be neither too high nor too low, and operations should be conducted effectively.

The heating section is divided into four segments with a direct combustion design. Each segment features thirty nozzles, totaling one hundred and twenty. The annealing process is at 1100°C, with the interior heat storage reaching a maximum temperature of 1250°C. Each heating segment is equipped with an oxygen content detector and a thermistor. There are five disc-shaped roller support components installed between different furnace segments, which are adept at quick roller changes on the line. Each disc roller component is paired with two silica-alumina fiber support rollers.

In the initial and final cooling zones, there are three stages of water spray cooling, with a particularly designed water management system. The initial cooling zone's first stage includes ten sets of nozzles on both sides of the plate strip, with each nozzle equipped with four spray nozzles, each paired with a manual production scheduling valve and a vacuum pressure gauge. This is to reduce the temperature of the plate strip from approximately 1100℃ to around 500℃. The final cooling zone, including the refrigeration stage, has three stages of refrigeration shells. Each refrigeration stage is fitted with eleven sets of AISI 304 weather-resistant steel spray tube heads, with eight nozzles on each tube, ensuring even water distribution through overlapping heads near the spray tubes. This results in the temperature of the plate strip typically dropping below 80℃ after the final cooling stage. The simple section includes a squeeze roller, a gas generator, and eight sets of hot air spray nozzles for drying, which makes the surface of the strip dry.