Role of Dilatometer in Designing New Bainitic Steels
Role of Dilatometer in Designing New Bainitic Steels
复制标题
膨胀计在设计新型贝氏体钢中的作用
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
H. Palkowski
中科院分区：
文献类型：
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作者：
M. Soliman;M. Asadi;H. Palkowski
采用热膨胀法对两种贝氏体钢进行了工艺参数设计。第一种是亚共析超细贝氏体钢，其硬度计用于确定在亚温退火（TC）期间贝氏体完全溶解的温度。然后选择高于TC的临界区退火温度。为了获得马氏体起始温度（MS），将钢从这些选定的温度淬火至室温（RT），然后将贝氏体转变温度选择为远高于MS。然后使用硬度计监测贝氏体转变动力学，由此估计贝氏体反应停止所需的时间范围。在第二类中，热机械处理的TRIP钢中产生了双峰贝氏体。在缓慢冷却之前，使用变形速率计进行三个变形步骤，以形成约。30%的多边形铁素体。然后将材料快速冷却至第一贝氏体形成温度。在该步骤期间，使用硬度计监测贝氏体反应，由此估计奥氏体分解50%所需的时间。通过淬火至RT定位未分解奥氏体的马氏体开始。然后在新的MSII之上进行第二次贝氏体转变步骤以形成第二代更细的贝氏体。
Dilatometric measurements were used to design the processing parameters of two types of bainitic steels. The first type is a hypoeutectoid ultra fine bainite steel, for which the dilatometer was used to locate the temperature at which cementite is completely dissolved during intercritical annealing (TC). The intercritical annealing temperatures are then selected will above TC. To obtain the martensite start temperatures (MS), the steel is quenched to the room temperature (RT) from these selected temperatures and then the bainite transformation temperatures were selected to be well above MS. The dilatometer was then used to monitor the bainite transformation kinetics from which the required time frames for cessation of the bainitic reactions were estimated. In the second type, bimodal bainite had been produced in thermo-mechanically processed TRIP-steel. A deformation dilatometer is used to perform three deformation-steps before slow cooling to form approx. 30% polygonal ferrite. The material was then rapidly cooled to the first bainite formation temperature. During this step, the dilatometer was used to monitor the bainite reaction from which the required time for 50% decomposition of austenite is estimated. The martensite start of the undecomposed austenite was located by quenching to RT. The second bainite transformation step was then performed well above the new MSII to form a second generation of finer bainite.