チタン添加熱延鋼板の加工熱処理法による強靱化と加工性の向上
1985 年 71 巻 9 号 p. 1140-1146
詳細
1985 年 71 巻 9 号 p. 1140-1146
Hot strip mills can be used for thermo-mechanically treating steels through various processing parameters of rolling and coiling. A laboratory simulation was carried out to study the relationship between the coiling temperature, microstructure, and mechanical properties of controlled rolled Ti-bearing steel. Decrease of a coiling temperature from 600°C to a low temperature such as 400°C significantly improved formability as well as low temperature toughness with a small change in strength.
This type of steel is strenghened mainly by TiC precipitation before coiling, especially during controlled rolling. The steel coiled conventionally at 600°C is strengthened further by additional TiC precipitation during slow cooling after coiling, while the steel coiled at about 400°C is hardened by bainite transformation instead of by such TiC precipitation. The bainite strengthening is responsible for improving formability and low temperature toughness.
The laboratory studies have led to the success in the production of 80 kgf/mm2 grade Ti-bearing steel with excellent formability and low temperature toughness.
