JPS5856642B2 - How to roll stainless steel hot strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling stainless steel hot strip.

Conventionally, in the manufacturing process of hot strip of stainless steel, especially austenitic stainless steel, after the steel material is hot rolled in a hot rolling mill, the temperature is 500°C to 6°C.
It is cooled at 00°C, wound up by a down coiler to become a hot coil, and then annealed in a continuous annealing and pickling line to facilitate cold working. In order to remove the existing scale, descaling is carried out by pickling.

If it were possible to omit the annealing process by directing the continuous annealing and pickling line, it would be possible to shorten the overall line length, increase line speed, and avoid line stoppages due to troubles caused by the combined line. Many benefits arise, such as reduction.

From this viewpoint, the present invention primarily aims to provide a method for omitting some steps in the hot strip manufacturing process of stainless steel, particularly austenitic stainless steel.

For this purpose, the inventor has conducted extensive research and experiments, and as a result,
We were able to develop a method that allows the necessary annealing to be performed during the hot rolling process without significantly impairing the production efficiency of the equipment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be explained below with reference to the accompanying drawings showing the outline of its implementation.

1. First, Figure 1 is a side view showing the arrangement of runout tables in a conventional hot rolling facility.
1 is a finishing rolling mill, 2 is a runout table, 3 is a pinch roll in front of a down coiler, 4 is a down coiler, and 5 is a wound hot coil.

When rolling is carried out using conventional hot rolling equipment as shown in this figure, the material to be rolled is usually
The temperature decreases due to the dissipation of radiant heat, and when it leaves the final stand 1, it is about 800°C.

Thereafter, it is cooled in the runout furnace 2 and reaches a temperature of about 500° C. in the down coiler 4.

The hot coil 5 of austenitic stainless steel finished at such processing temperatures is work hardened, and unlike ordinary steel, pickling alone will cause many troubles during subsequent cold rolling.

For this reason, it is common for the steel to be treated again using a combined annealing and pickling line.

On the other hand, FIG. 2 shows a side view of the arrangement of the apparatus for carrying out the method of the present invention. In the figure, numerals 1 to 5 are the same as in FIG. 1, 6 is a high frequency power source, and 7 8 indicates a high-frequency heating device, and 8 indicates a cooling device.

As the heating device 7, for example, as shown schematically in FIG. 3, the strip 10 passes through a high-frequency coil 7', or as shown schematically in FIG. from the side edge of the electrode T'
, 7'' to cause a high frequency current to flow into the strip 10. Various methods are conceivable.

In the present invention, as shown in FIGS. 2 to 4, the hot strip at about 800°C from the hot finishing mill 1 is
The temperature of the phase transformation region, for example 1
000 to 1,150°C, and then lowered to below the phase transformation region, for example, below 500°C, using a cooling device 8 such as a water quench, to uniformly recrystallize the metal structure and undergo solution heat treatment. The hot coil 5 is then wound up.

In this way, the heat-treated hot coil 5 is already suitable for the next step of cold rolling, and only the surface descaling is required.

Therefore, according to the method of the present invention, the processing line can be made significantly simpler than the conventional method.

In addition, there is no need for pickling, and surface scale etc. can be removed just by polishing, so conventionally,
Compared to the conventional process of polishing the button surface after passing through the annealing and pickling line, it is possible to significantly reduce the number of steps.

In addition, in the method of the present invention, the amount of heat in the rolled material when it exits the hot finishing mill can be used as thermal energy for IT annealing, so it has great advantages from the perspective of energy saving. It is extremely effective industrially.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the arrangement near the runout table in a conventional hot rolling mill, Fig. 2 is a side view showing the arrangement near the runout table when the method of the present invention is implemented, and Figs. 3 and 4 are FIG. 2 is an explanatory diagram showing different examples of high-frequency heating devices for carrying out the method of the present invention. 1...Finish rolling mill, 2...Runout table, 3...Pinch roll in front of down coiler, 4...Down coiler, 5...・Hot coil, 6...High frequency power supply, 7...
・High frequency heating device.

Claims (1)

[Claims] 1. In rolling stainless steel hot strip, the hot strip leaving the hot rolling equipment is peeled immediately after the hot rolling equipment and reheated to a temperature in the phase transformation region, and then,
A method for rolling stainless steel hot strip, which comprises rapidly cooling the stainless steel hot strip to a temperature below a phase transformation region and then winding it. 2 After hot rolling austenitic stainless steel, 10
The method according to claim 1, wherein the material is reheated to 00°C to 1150°C and then rapidly cooled to 500°C or less.