为减少汽车废气再循环(Exhaust Gas Recirculation,EGR)管件三维弯曲缺陷,提高成品率,本文建立了304不锈钢本构模型,采用数值仿真与实验相结合方法对模型成形参数中相对壁厚、相对半径对管材的最大主应变、最大壁厚减薄率等影响因素进...为减少汽车废气再循环(Exhaust Gas Recirculation,EGR)管件三维弯曲缺陷,提高成品率,本文建立了304不锈钢本构模型,采用数值仿真与实验相结合方法对模型成形参数中相对壁厚、相对半径对管材的最大主应变、最大壁厚减薄率等影响因素进行探索,分析相对壁厚、相对弯曲半径对管材弯曲过程中成形质量的影响.结果表明,管材在弯曲成形过程中,相对壁厚越小,相对弯曲半径越小,则管材越容易产生裂纹以及失稳起皱等缺陷;随着弯曲角度的增大,管材弯曲最大壁厚减薄率值的增大趋于平缓.对于易发生塑性变形的金属材料,其相对壁厚及相对弯曲半径的取值是否合适是减少其裂纹产生的关键因素.故研究结果可为获得高质量的管件提供理论支撑.展开更多
The texture and grain boundary of 00Cr12 Ti FSS have a close correlation with properties and should be controlled to optimize the performance of steel sheets. In this paper, the macrotexture evolution during recrystal...The texture and grain boundary of 00Cr12 Ti FSS have a close correlation with properties and should be controlled to optimize the performance of steel sheets. In this paper, the macrotexture evolution during recrystallization annealing was investigated by XRD, the microtexture and grain boundary distribution evolution during recrystallization annealing were investigated by EBSD. The results showed that the γ fiber texture were mainly generated by replacing α fiber texture in recrystallization process. But with the holding time extending,γ fiber texture transferred to other texture after the holding time got to a certain degree. The major CSLs in 00Cr12 Ti FSS after recrystallization are Σ3 and the frequency of Σ3 climb up and then decline with the holding time extending.Σ11 plays an important role in the process of recrystallized γ fiber texture formation.展开更多
The load distribution of multi-row bearings of large strip rolling mill is fully analyzed by 3D contact boundary element method （BEM）. It is found out that bearings are frequently worn out due to serious uneven load...The load distribution of multi-row bearings of large strip rolling mill is fully analyzed by 3D contact boundary element method （BEM）. It is found out that bearings are frequently worn out due to serious uneven load on the multi-row rollers. The constraint mechanism of the previous rolling system is found to be unreasonable by theoretical analysis on heavy machinery structure. A mechanism of self-aligning even load for workroll bearing of 2 050 mm hot rolling mill of Baoshan I＆S Co. is developed. This device is manufactured with particular regard to the structure of 2 050 mm hot rolling mill mentioned above. Hence, uneven load on multi-row bearings is greatly relieved and their lives are remarkably prolonged. Meanwhile, theoretical analysis and on-spot tests prove the rationality and validity of the device.展开更多
文摘为减少汽车废气再循环(Exhaust Gas Recirculation,EGR)管件三维弯曲缺陷,提高成品率,本文建立了304不锈钢本构模型,采用数值仿真与实验相结合方法对模型成形参数中相对壁厚、相对半径对管材的最大主应变、最大壁厚减薄率等影响因素进行探索,分析相对壁厚、相对弯曲半径对管材弯曲过程中成形质量的影响.结果表明,管材在弯曲成形过程中,相对壁厚越小,相对弯曲半径越小,则管材越容易产生裂纹以及失稳起皱等缺陷;随着弯曲角度的增大,管材弯曲最大壁厚减薄率值的增大趋于平缓.对于易发生塑性变形的金属材料,其相对壁厚及相对弯曲半径的取值是否合适是减少其裂纹产生的关键因素.故研究结果可为获得高质量的管件提供理论支撑.
基金Funded by the National Natural Science Foundation of China(No.51805279)the Natural Science Foundation of Zhejiang Province(No.Q17E050012)+1 种基金the Natural Science Foundation of Ningbo(No.2016A610057)the Sponsored by KCWong Magna Fund in Ningbo University
文摘The texture and grain boundary of 00Cr12 Ti FSS have a close correlation with properties and should be controlled to optimize the performance of steel sheets. In this paper, the macrotexture evolution during recrystallization annealing was investigated by XRD, the microtexture and grain boundary distribution evolution during recrystallization annealing were investigated by EBSD. The results showed that the γ fiber texture were mainly generated by replacing α fiber texture in recrystallization process. But with the holding time extending,γ fiber texture transferred to other texture after the holding time got to a certain degree. The major CSLs in 00Cr12 Ti FSS after recrystallization are Σ3 and the frequency of Σ3 climb up and then decline with the holding time extending.Σ11 plays an important role in the process of recrystallized γ fiber texture formation.
基金This project is supported by National Ninth-five Key Technologies R&D Program of China(No.9552801-0201)National Natural Science Foundation of China(No.50575155).
文摘The load distribution of multi-row bearings of large strip rolling mill is fully analyzed by 3D contact boundary element method （BEM）. It is found out that bearings are frequently worn out due to serious uneven load on the multi-row rollers. The constraint mechanism of the previous rolling system is found to be unreasonable by theoretical analysis on heavy machinery structure. A mechanism of self-aligning even load for workroll bearing of 2 050 mm hot rolling mill of Baoshan I＆S Co. is developed. This device is manufactured with particular regard to the structure of 2 050 mm hot rolling mill mentioned above. Hence, uneven load on multi-row bearings is greatly relieved and their lives are remarkably prolonged. Meanwhile, theoretical analysis and on-spot tests prove the rationality and validity of the device.
