Austenitic stainless steel hot-rolled thick plates use medium frequency induction heating equipment for solution treatment. How to choose the heating rate?

We usually use medium frequency induction heating equipment to perform solution treatment on austenitic stainless steel hot-rolled thick plates. During the entire heat treatment process, there are many factors that affect the effect of solution treatment, such as heating temperature, heating rate, cooling temperature, etc. Therefore, it is very necessary to choose the appropriate heating temperature, heating rate, and cooling temperature. Today, the editor will tell you how to choose the heating rate during solid solution treatment.

The magnetic permeability of austenitic stainless steel does not change above and below the Curie point, and is equal to 1. In addition, the thermal conductivity of steel is relatively low, so it is difficult to heat. In the heating process of solid solution treatment using medium frequency induction heating equipment, it is necessary to use a larger surface power density and a longer heating time to achieve certain results.

Austenitic stainless steel hot-rolled thick plates, the surface power density used for solution treatment heating is 60-160W.cm-2, the temperature rise rate during heating reaches 8-20℃.S-l, and the advancing speed of the steel plate at this time is 60-120mm .min-1.

According to the surface power density of 150W.cm-2, the heating steel plate size is 540mm wide, 40mm thick, and the steel plate forward speed is 60mm.min-1 when passing through the sensor. It can be seen from the heating curve of the steel plate (sensor length is 240mm) that during the heating process , the temperature rises basically uniformly along the cross section of the steel plate, and the temperature along the edge area of the steel plate is slightly lower than the central area. Before the steel plate leaves the sensor, the temperature difference between the two areas is about 50°C. After the steel plate leaves the sensor, the temperature difference between the two areas is 30°C. It can be seen that when a longitudinal magnetic field is used to heat austenitic stainless steel thick plates, the temperature distribution is uniform. When the 40mm thick plate is heated to 1000°C, the temperature difference between the edge and the center is only 30°C. In order to make the temperature of the steel plate more uniform, after the steel plate completes solid solution heating, it is uniformly heated for 1-2 minutes and then cooled by water spray. This ensures a more even temperature. To this end, the solid solution heating temperature can be appropriately increased by about 20°C to ensure that the steel plate temperature after equalization is not lower than the lower limit of the solid solution temperature.

In short, for an austenitic hot-rolled steel plate with a thickness of 30-50mm, when heated with a surface power density of 140-160W·cm-2, the advancing speed of the steel plate is 80-100mm.min-1, and the average heating rate of solution treatment It is 5-6℃.s-l, which can maintain the uniformity of the temperature of the steel plate, and the temperature difference between the edge and the center is within 30℃.