Houfa SHEN
,
Richard A.Hardin
,
Robert MacKenzie
,
C.Beckermann
材料科学技术（英）
A three-dimensional heat transfer model for continuous steel slab casting has been developed with realistic spray cooling patterns and a coupled microsegregation solidification model that calculates the solidification path for multi-component steels. Temperature and composition dependent properties are implemented in a database for 15 chemical species.Considerable effort is made to accurately model the spray cooling heat transfer. Each spray nozzle position and distribution is considered, including variations of the spray patterns with flow rate,and spray overlap. Nozzle type,layout, nozzle-to-slab distance, and spray span and flux are variable.Natural convection, thermal radiation and contact cooling of individual rolls are computed. The present model provides more comprehensive information and realistic slab surface temperatures than results from a model using the “averaged” treatment of boundary conditions. Cooling operating conditions and parameters of individual spray nozzles can be analyzed to optimize nozzle spray distribution, improve product quality, and troubleshoot issues such as nozzle clogging that may arise during production. One spray cooling correlation is used for the entire machine, achieving as good or better agreement with surface temperature measurements than was found previously for the model using an “averaged” treatment of boundary conditions and using three machine-segment-dependent correlations.
关键词:
Steel
,
null
,
null
肖玄
,
陈敏
,
伍永刚
机械工程材料
采用透射电镜、扫描电镜和电子背散射衍射系统等对铅浴淬火处理的珠光体钢丝以及经不同道次冷拔后钢丝的显微组织与织构进行了分析.结果表明:铅浴淬火处理后钢丝重新形成了无畸变的等轴晶粒,且获得了均匀的索氏体组织;钢丝在冷拔过程中,珠光体片层间距和渗碳体片层厚度随着钢丝直径减小而近似呈线性减小,渗碳体片层具有一定的塑性变形能力;在整个冷拔变形过程中,钢丝心部、中部和边部各区域的铁素体基体协调变形,平行于拉拔方向的铁素体<110>丝织构组分的面积分数逐渐增加,但其增加速度在某一区域内并不是不变的,而是具有交替性;随着真应变增大,<110>丝织构的强度不断增加,非关联最小取向差-频率曲线偏离Mackenzie分布,并在10°～20°和45°～60°取向差范围内出现峰值.
关键词:
铅浴淬火钢丝
,
显微组织
,
织构
,
取向差
