1939 年 25 巻 3 号 p. 175-187
The author deals with the results of some experiments carried out on polished steel plates for deep-cupping which are adopted to motor-cars, furniture, electric apparatus, etc.
1) Relation between the working procedures and the properties of material.
For the material cold-rolled after pickling, there are three processes, i e., the direct use of the material as hot-rolled, the use of material worked after normalising or annealing. In comparing the three processes with respect to the working procedure and properties of material, the hot-rolled material is disadvantageous in its high hardness and difficulty in cold-rolling, but the operation is simple as a superior product with fine grains is obtainable by reducing the rate of cold rolling. Particularly, with a continuous-working equipment for the constant hot-rolling operation, the advantage is more conspicuous. The annealed material is not suitable for deep-cupping due to its coarse grains unless the rate of cold-rolling is made extremly high, the process being disadvantageous as it takes a considerable time for operation. The normalised material has properties between the first and the second one and the working heterogeneity accompanied with the hotrolling is well adjusted, the process being considered to be advantageous.
2) Relation between the strength of cold rolls and the properties of material.
The material rolled to 40% by passing it 6 times under the heavy reduction of a four high rolling mill and that rolled to 40% by passing it 48 times through a three high rolling mill were compared with respect to their properties after both having been annealed. The results indicate that the former is stronger with a larger elongation and is superior in the cupping
3) Comparison between the rimmed steel and the killed steel properties.
The steel sheets were experimentally made with three kinds of material, i. e., the dead-soft rimmed steel, the killed steel for black Sheet and the killed steel made by an electric furnace. In comparing the properties of the three materials, the killed steel is higher in the strength, and is inferior in the repeated bending but the Erichsen value and the cupping results are similar to the rimmed one.