SS330、SS400连铸连轧板卷通条力学性能探讨

通过对SS330、SS400连铸连轧板卷通条力学性能和检验试样代表性的研究,得出唐钢薄板坯连铸连轧控冷工艺制度合理,热轧板带钢通条力学性能、金相组织均匀。距成品带钢尾端4m处试样的性能对整个板卷的性能具有很好的代表性。     

Characteristics of deformation joining of aluminum-stainless steel composite sheet

1　INTRODUCTIONAseveryoneknows ,aluminumandstainlesssteelaredifficulttoweldtogether[16 ] .Inthepast,braz ing ,projectionweldingaswellasaluminizingwereused .Nowadays ,anewmethodisputforward ,inwhichthealuminumsheetandstainlesssteelsheetheatedbyinductionheaterareconnectedbypressureofascrew press .Notonlycanthismethodimprovebondingbehaviorofthecompositesheet,butalsocanitraisetheproductivity greatly .Thistechnologyiscalleddeformationjoining ,i.e .pressjoining .InChi na ,ithasbeensuccessfully…     

拉深筋对板厚减薄量的影响

利用数值模拟的方法,着重研究了板料通过半圆形拉深筋和矩形拉深筋时板厚的变化规律和特点,分析了板料通过拉深筋时影响板厚减薄的主要因素,为探索板料通过拉深筋后的后续可成形性提供理论基础。研究结果表明,板料通过拉深筋时的弯曲变形是导致板厚减薄的根本原因,同时减薄量还受到板内张力及变形程度的影响。并指出累积等效应变不适于用来评价板料通过拉深筋后的变形程度。     

Eliminating springback error in U-shaped part forming by variable blankholder force

Springback is the main concern in U-shaped part forming, which would adversely affect desired part geometries. The use of variable blankholder force in the forming process is one effective method to reduce springback. However, there has not been a systematic way to determine the blankholder force trajectory. In this article, a methodology of obtaining this blankholder force trajectory in forming a U-shaped part that considers the wrinkling limit and fracture limit in the forming process was proposed. The method was validated numerically by using the Finite Element Method to simulate the benchmark of a 2-D draw bending problem in NUMISHEET’93. With the calculated blankholder force trajectory, higher forming quality was obtained and compared with constant blankholder force cases. Springback was kept at a minimum while avoiding cracking.     

电场退火对08Al深冲钢板再结晶织构的影响

利用X射线衍射ODF分析方法，研究了电场对08Al深冲钢板单台阶退火和双台阶退火再结晶织构的影响。结果表明：电场提高了再结晶γ纤维织构的强度，同时降低了再结晶α纤维织构的强度。产生上述结果的主要原因是由于电场降低了各取向的形变储能，从而抑制了储存能小的取向晶核的形成及长大，促进了储存能大的再结晶γ取向晶粒的择优生长。     

"挤压-轧制"对Al-Pb合金板材微观结构与力学性能的影响

研究了Al-Pb合金制成板材过程中“挤压-轧制”对板材微观结构与力学性能的影响。结果显示，Al-Pb合金变形前Pb分布在枝晶间隙或“嵌”在基体中；合金热挤压成板材后，合金颗粒内部的Pb细化，但变形颗粒新生表面的Pb粗化，在随后的轧制变形及热处理时难以消除“Pb粗化”造成的遗传影响。合金板材的铝基体发生再结晶前，力学性能主要受Pb形貌影响；发生再结晶后，力学性能主要受基体微观结构影响。     

基于代理模型的板料成形优化技术进展

综述了板料成形优化技术现状,针对优化中计算成本高的问题,提出了基于代理模型的优化技术,包括可立格模型、响应面模型、神经网络模型等。从实验设计、代理模型的建立,以及优化求解等方面进行了阐述。针对产品设计中因素的随机性和不确定性,为减小目标函数对设计变量的敏感性,将稳健设计理论应用于板料成形优化中,以提高产品的可靠性和稳健性。     

基于有限元仿真的金属板材单点渐进成形分析

目前对板材单点渐进成形新型工艺的研究多是通过物理试验,从金属宏观位移的角度分析成形过程的一般规律,研究成形参数对成形能力的影响,而无法获得成形过程中真实的变形过程。文章基于刚粘塑性有限元法,应用实体单元,对渐进成形中在直线轨迹和曲线轨迹下的板材成形过程进行数值模拟,分析成形过程中各部分应力、应变的特点,并深入探讨了渐进成形过程的成形机理。研究表明,成形过程中,变形区可以划分为4个具有显著差异的区域考察变形特点;在工具头局部成形时,变形金属在压应力的作用下变形,具有更高的成形极限。     

Finite element analysis of tailored sheet forming processes considering laser welding zone

The finite element formulation for predicting strain distributions and weld line movements in the forming processes of tailored sheet metals is developed. The material properties of the welding zone such as strength coefficient, work-hardening exponent, and plastic anisotropic parameter are analytically obtained from those of base metals based on the tensile tests. The welding zone is modelled with the several, narrow finite elements called by weld elements. To verify the finite element formulation for tailored blanks, the forming processes of autobody door inner panel section and hemispherical dome are simulated. FEM predictions are compared and showed good agreements with experimental measurements.     

Mechanism of Springback-Free Bending of High-Strength Steel Sheets under Warm Forming Conditions

Tensile loading-unloading tests of high-strength steel sheets in an elevated temperature range are conducted using a 100 kN servo-controlled hydraulic dynamic fatigue testing machine, aiming at clarifying the mechanism of the springback-free phenomenon occurring in warm sheet forming. From stress-strain curves obtained by the tests, it is found that the abrupt decrease in the springback of formed steel sheets at approximately 750 K in isothermal v-bending tests is mainly caused by high-temperature transient creep deformation. Also, from the results obtained by the isothermal v-bending test, bending-unbending deformation observed at temperatures higher than 750 K, as a result of high-temperature creep, was found to have a secondary effect in the springback-free phenomenon.