Advances in Physical Metallurgy and Processing of Steels. Development of Steel Plates by Intensive Use of TMCP and Direct Quenching Processes.

Abstract

Historical progress of Thermo-Mechanical Processing (TMP) in steels during a last half century is briefly reviewed in the first part of this paper. On-line accelerated cooling process in a wide plate mill was developed by a Japanese steel mill in the end of 1970's, and its equipment was installed into major steel plate mills in Japan and Europe in 1980's. The combination of controlled rolling and accelerated cooling called as TMCP provided a powerful means for microstructural control of hot rolled steel plates. Subsequently, direct quenching (DQ)-tempering process was industrialized, where direct quenching after finish-rolling was performed at the highest cooling rate available in the accelerated cooling equipment. Since then, various new steel plates have been developed by intensive use of TMCP and direct quenching process particularly in Japan. In the latter part of this paper, newly developed steel plates by use of TMCP or DQ process during last two decades were summarized based on classification of line pipe steel, weldable HSLA steel plates used for shipbuilding, offshore construction, building, bridge or penstock, and austenitic stainless steel plate. Various strengthening mechanisms such as grain refinement, precipitation hardening or strengthening due to transformed microstructures have been utilized in development of numerous TMCP and DQ steel plates.

Uma breve revisão histórica do desenvolvimento da soldagem dos aços API para tubulações

“…Os primeiros estudos para o desenvolvimento dos aços ARBL ocorreram na Europa, entre as décadas de 1950 e 1960, no BISRA (British Iron and Steel Research Association) [20]. Neste, foram estudados os diversos fenômenos metalúrgicos que ocorrem durante o processamento termomecânico [21][22][23][24][25][26][27][28].…”

“…A Tabela 1 apresenta a composição química dos aços X100 e X120 experimentais utilizados pelas referências [20,33,46,[48][49][50] e a Tabela 2 apresenta as propriedades mecânicas de limite de escoamento (LE), limite de resistência à tração (LR) e a relação entre LE/LR desses materiais. Na Tabela 3 pode-se observar as propriedades mecânicas e o valor do carbono equivalente dos aços X100 e X120 em comparação com os aços X80.…”

“…Na Tabela 3 pode-se observar as propriedades mecânicas e o valor do carbono equivalente dos aços X100 e X120 em comparação com os aços X80. Pode-se observar que para os valores de energia absorvida no ensaio de impacto (Charpy V) há uma grande variação entre os graus, sendo esta propriedade determinada pela aplicação final da tubulação [20,46,47,49].…”

“…Propriedades mecânicas e o valor do carbono equivalente dos aços X100 e X120 em comparação com os aços X80 [20,46,47,49]. dispersos pela matriz ferrítica), permanecendo nesta temperatura o tempo necessário.…”

Effect of tempering temperature on microstructures and properties of niobium and titanium microalloying low carbon bainite steel

“…Especialy in engineering machinery area, along with the development trends of large scale and lightweight, request for higher yield strength, impact toughness and welding performance of the structural parts has been put forward. At present, the widely used bainite steel with the yield strength of 460 MPa or 550 MPa is mainly prepared by a low cost process named TMCP [1], for the higher yield strength bainite steel, it is widely manufacturated by tempering after reheating and quenching process [2]. As the cost of tempering after reheating and quenching is high, so using tempering after TMCP process to instead it is of great significance.…”