[材料科学]高性能管线钢的断裂控制和合金设计-意大利材料研究中心-保罗CENTRO SVILUPPO MATERIALI SpA Dr Mauro.ppt

Content Metallurgical design development: CSM general approach Linepipe vs plate requirements Microstructure vs Mechanical properties Metallurgical modelling Key process parameters for high grade TMCP plates Comparison between plate and strip rolling PLATE ROLLING Sound experience in heavy wall high grade plate production Reversing mill are used both on roughing and finishing No problem in waiting after roughing and finish rolling at low temperature (down to Ar3+10°C) Interrupted accelerated cooling is followed by air cooling STRIP ROLLING Rolling temperature should be lowered with respect to commercial strip product TMCP concept should be applied: total reduction below Not Recrystallization Temperature 65% Not easy to obtain high thickness (coiling?) Coiling after cooling can bring to tempering effect on microstructure PLATE ROLLING Sound experience in heavy wall high grade plate production Reversing mill are used both on roughing and finishing No problem in waiting after roughing and finish rolling at low temperature (down to Ar3+10°C) Interrupted accelerated cooling is followed by air cooling STRIP ROLLING Rolling temperature should be lowered with respect to commercial strip product TMCP concept should be applied: total reduction below Not Recrystallization Temperature 65% Not easy to obtain high thickness (coiling?) Coiling after cooling can bring to tempering effect on microstructure X70 fine-grain (? 5 mm) ferrite reduced pearlite X80 mixed ferrite/ granular bainite MA islands Typical microstructures Microstructure vs Mechanical properties Typical microstructures X70 fine-grain ferrite (? 5 mm) reduced pearlite Microstructure vs Mechanical properties Typical microstructures X80 mixed polygonal ferrite/granular bainite MA islands Microstructure vs Mechanical properties * Matrix phase and Mechanical Properties 1) Tensile strength size or relevant substructure unit: cell or lath in bainite mainly controlled by transforma