Investigation of Metallurgical Factors in the Production of High Strength Steel Plate with High Toughness by Controlled Rolling

Development of a New Armor Steel and its Ballistic Performance

“…This kind of microstructure includes a ferritic matrix and intensively dispersed precipitates at the interfaces of ferrite laths. These precipitates are mainly cementite but secondary carbides can also take place in the matrix due to tempering at 500 °C -600 °C 15,16 . The secondary carbides in the matrix increase the hardness and strength of the steel depending on the density per unit volume and the interaction with dislocations in addition to having coherent or semi-coherent interfaces 17 .…”

Evaluation of Cooling Performance in Intensive Cooling with High Water Flow Rate and Effect of Controlled Rolling Just after Cooling on Mechanical Properties

“…Naoki NAKATA, 1) * Takashi KUROKI, 2) Akio FUJIBAYASHI, 2) Yoshimichi HINO 3) and Yoshio UTAKA Laboratory tests were conducted in order to quantify the cooling performance of intensive inter-pass water cooling, which was introduced as an effective method for increasing productivity of high strength steel plates.…”

“…3,4) As controlled rolling does not require large-scale accelerated cooling equipment and temperature control is relatively easy, it was applied earlier than controlled cooling. For example, in the controlled rolling process at a plate mill, 60% reduction at 800°C is given as the target of applied strain in the designated temperature range.…”

Thick Plate Technology for the Last 100 Years: A World Leader in Thermo Mechanical Control Process

“…In the second half of rolling, grain elongation is promoted because rolling is performed in non-recrystallization region, deformation bands which form nucleation sites for subsequent transformation are introduced in the grains, and ferrite grains are refined. [18][19][20] If accelerated cooling is combined with this controlled rolling process, austenite can be supercooled, and this adds a mechanism for further grain refinement by the ferrite low temperature transformation effect (increase of transformation nuclei and suppression of grain growth) and transition from pearlite to the bainite transformation by the quenching effect. When the steel composition includes precipitation-hardening elements such as Nb, Ti, V, etc., precipitation occurs during air cooling after interruption of water cooling; this also contributes to precipitation hardening, and as a result, it is possible to secure strength without heavy addition of alloying elements.…”