鼓形挤压拉伸芯头的加工工艺

主要介绍了在铝合金挤压拉伸模具中,决定管型材内孔尺寸用的鼓形挤压拉伸芯头的加工方法、加工要点和加工过程。

铝镁合金半圆球工件挤压拉伸加工工艺研究

针对制作材料为5A06牌号的铝镁合金浮球,小批量生产工件,制作时分两半圆球压制拉伸,再组焊成球的工艺过程以及在以往挤压拉伸半圆球的生产过程中次品、废品高,造成施工成本较高的现象,通过理论计算和借鉴以往的加工经验,对半圆球挤压拉伸的膜具、工艺流程进行了改进。经多次试验取得了良好的效果,产品合格率达到98%以上。

矩形管挤压拉伸工艺及模具设计

针对我厂矩形管(90mm×60mm×2.0mm)生产中存在的尺寸精度及表面质量低的问题,从理论分析其产生原因,并对原生产工艺及模具设计进行改进,提出了合理的改进方案,经生产后产品各项技术指标均满足用户的使用要求。

阶梯件拉伸挤压复合模设计

通过分析零件的工艺特点 ,设计了拉伸挤压复合模 ,不仅可提高零件质量 ,而且可提高生产效率。

大规格钛铜棒挤压-拉伸工艺研究

宽度为101mm的大规格矩形钛铜棒,以挤压状态交货,产品尺寸精度低,表面质量差,挤压沟条严重,与用户预期相差较远。文章研究了大规格钛铜棒的挤压-拉伸生产工艺,通过模具设计、工艺优化,采用表面抛光设备等途径,可实现产品质量的提升。

提高6082铝合金薄壁管材伸长率的试验研究

针对实际生产中,用户对表面质量要求极其严格的6082铝合金薄壁管材伸长率不达标的情况,通过对该合金成分、时效制度及挤压拉伸率进行调整试验,探究6082铝合金管材力学性能和表面质量的影响因素。结果表明:适量降低合金成分中锰、镁和硅的含量,并采用1%的挤压拉伸量,以及165℃6 h的欠时效处理制度,既可保证管材光滑的表面质量和强度性能要求,又可使其伸长率提高至10%以上。

表面对称电极含金属芯聚偏二氟乙烯纤维的简谐振动传感器

模仿蜘蛛毛发感受器的结构和功能,设计制备了表面对称电极含金属芯聚偏二氟乙烯(PVDF)纤维(SMPF)的简谐振动传感器。用挤压拉伸的方法制备纤维胚体,将纵向表面涂镀形状完全对称的导电胶作为外部电极,经过极化后,制备成SMPF简谐振动传感器。基于压电方程和振动理论,建立了悬臂梁结构的SMPF简谐振动传感器的理论模型,分析了传感信号与简谐振动角度和幅值的关系。将SMPF简谐振动传感器固定在基体上,搭建了实验系统,测试了SMPF简谐振动传感器对简谐振动的响应,验证了理论模型。结果表明,SMPF简谐振动传感器能够准确感知简谐振动的频率,传感信号和简谐振动的幅值呈线性关系,和振动方向成"8"字形关系,共振频率为15.6Hz,灵敏度为0.019pC/mm。该SMPF传感器能够测量简谐振动频率、幅值或方向,具有广泛的工程应用前景。

抛物线形零件的成形工艺与模具设计

简要介绍了抛物线形零件的成形工艺,详细叙述了该零件的拉伸工艺及模具结构设计。

农用抛秧盘成型模具的改进设计

农用抛秧盘成型模是秧盘成型机的重要部件,冷却方式的合理选择、冷却系统结构的合理设计,不仅可以大大简化加工工艺,降低制造成本,而且可以极大地保证和提高秧盘质量和产量,延长模具本身的使用寿命,降低维修成本,使秧盘成型机的整机性能大大改善。通过对农用抛秧盘成型模原理和结构,以及各组成部分功能作用的分析,可以确定农用抛秧盘成型模的改进设计方案,通过数据分析、实验和应用,达到了改进的目的。

Microstructures and tensile properties of as-extruded Mg-Sn binary alloys

The microstructure and mechanical properties of Mg-xSn （x-3, 7 and 14, mass fraction, %） alloys extruded indirectly at 300 ℃ were investigated by means of optical microscopy, scanning electron microscopy and tensile test. The grain size of the a-Mg matrix decreases from 220, 160 and 93 μm after the homogenization treatment to 28, 3 and 16 μm in the three alloys after extrusion, respectively. The results show that the grain refinement is most remarkable in the as-extruded Mg-7Sn alloy. At the same time, the amount of the Mg2Sn particles remarkably increases in the Mg-7Sn alloy with very uniform distribution in the a-Mg matrix. In contrast, the Mg2Sn phase inherited from the solidification with a large size is mainly distributed along grain boundary in the Mg-14Sn alloy. The tensile tests at room temperature show that the ultimate tensile strength of the as-extruded Mg-7Sn alloy is the highest, i.e., 255 MPa, increased by 120% as compared with that of as-cast samples.

Effect of ECAP on microstructure and tensile properties of A390 aluminum alloy

The purpose of the present research is to determine the tensile strength and elongation of the A390 alloy processed by ECAP and to reveal the relationship between the microstructure and tensile properties. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used for microstructural analysis of the samples. The results of the mechanical testing showed that the ultimate tensile strength (UTS) increased from 142 MPa for the as-cast sample to 275 MPa for the sample after the third ECAP pass. Increasing the ECAP passes up to 4 led to a remarkable enhancement of elongation compared with the as-cast sample. It was found that the improvement of strength and ductility of A390 alloy with increasing the number of ECAP passes was attributed to the homogenous distribution of particles, reduction of particle size, and elimination of voids especially adjacent to the primary silicon particles. The results of fractography demonstrated that when the number of ECAP passes increased to 4, the uniform round dimples formed and the relatively brittle as-cast sample transformed to a ductile alloy.

Effect of heat treatment on microstructures and mechanical properties of extruded-rolled AZ31 Mg alloys

The deformation behaviors of extruded-rolled(ER)AZ31 Mg alloys with different rolling reduction and heat treatment were investigated.The results show that the accumulation of rolling reduction increases the density of twins,and refines the grain structures,which are in accordance with the enhanced strength and degraded plasticity.Tensile strength and plasticity of the alloy depend mainly on rolling reduction,while heat treatment temperature plays a more important role than heat treatment time at the same rolling reduction.With the increase of rolling reduction,the plasticity becomes more sensitive than strength on heat treatment. Recrystallization of extruded-rolled alloys will occur easily with deformation increasing,which is induced by addition of distortion energy.

Influence of homogenizing on mechanical properties of as-cast AZ31 magnesium alloy

Forward extrusion experiments of as-cast AZ31 magnesium alloy were conducted at different temperatures and different extrusion ratios using the as-cast billets with and without homogenizing treatment.The mechanical properties of pre-and post-extrusion of the two kinds of billets were investigated.Experimental results show that the mechanical properties of post-extrusion of the two kinds of billets all are obviously improved compared with those of pre-extrusion.The elongation of post-extrusion using the billet with homogenizing is higher than that without homogenizing,but the tensile strength is lower than that without homogenizing.When the extrusion ratio increases,the elongation and tensile strength of post-extrusion of two kinds of billets all will increase obviously.When the extrusion temperature of billet without homogenizing increases,the tensile strength of post-extrusion will decrease obviously and the elongation of post-extrusion will change to a small extent.For the billet with homogenizing,the tensile strength of post-extrusion will decrease in some sort when extrusion temperature increases.

High temperature tensile behaviors of extruded and rolled AZ31 Mg alloy

High temperature tensile ductilities and deformation mechanisms of an extruded and rolled AZ31 Mg alloy were investigated.Elongation-to-failure tests were conducted under constant T-head velocity and constant temperatures ranging from 300℃ to 450℃.Strain-rate-change tests were conducted under varying strain rate from 5×10-5s-1to 2×10-2s-1and constant temperature from 300℃ to 450℃.Experimental results show that the maximum elongation of the AZ31 alloy with an average grain size of about 19μm is 117%at strain rate of 10- 3s-1 and temperature of 450℃.Stress exponent and activation energy were characterized to clarify the deformation mechanisms.The enhanced ductility is dominated by solute drag dislocation creep,and the major failure mechanism is cavity growth and interlinkage.

Microstructure and tensile properties of as-extruded Mg-Sn-Y alloys

The microstructure and tensile properties of the Mg-1.0%Sn-xY(x=1.5%,3.0%,3.5%,atom fraction)alloys extruded indirectly at 350℃ were investigated by means of optical microscopy,scanning electron microscopy and tensile test.The mean grain sizes ofα-Mg matrix in the three extruded alloys are 6,8 and 12μm,respectively,slightly increasing with the addition of Y. The relationship between microstructure and strength was discussed in detail.The results show that the addition of Y has little effect on the grain refinement of the as-extruded Mg-Sn based alloys above.The only MgSnY phase is detected in the Mg-Sn-1.5%Y alloy, and the Sn3Y5 phase in the Mg-Sn-3.5%Y alloy,whereas both of them simultaneously exist in the Mg-Sn-3.0%Y alloy.The particle shape of MgSnY and Sn3Y5 phase,inherited from the solidification,has little change before and after hot extrusion.Mg-Sn-3.0%Y alloy has the highest ultimate tensile strength(UTS),305 MPa,by over 50%compared with that of the other two alloys.

Strengthening and stress drop of ultrafine grain aluminum after annealing

Ultrafine grain pure aluminum was produced by equal channel angular pressing and cold rolling, the deformed aluminum was annealed at 200 ℃ for 1 h. The tensile curves of deformed and annealed aluminum show that yield strength of deformed aluminum increases by 100%-300% and its elongation decreases by about 20%. After low temperature annealing, strength of annealed aluminum increases by 20% and elongation decreases by over 50%, the recovery of dislocations may be the main cause of annealing strengthening. In addition, there is an abrupt stress drop in the tensile curves of annealed aluminum and the formation of shear band is responsible for it.

Microstructures and mechanical properties of extruded Mg-1Mn-3.5Y and Mg-1Mn-1Y-2.5Nd alloys

Both Mg-1Mn-3.5Y and Mg-1Mn-1Y-2.5Nd alloys（mass fraction,%）were extruded at 380？C.Most of the（10^-10） crystal planes in the Mg-1Mn-3.5Y alloy are parallel to the normal direction,while most of the（10^-11）crystal planes in the Mg-1Mn-1Y-2.5Nd alloy are parallel to the normal direction.The tensile tests at room temperature,100℃ and 200℃ show that the Mg-1Mn-3.5Y alloy exhibits higher yield strength,but lower elongation to failure as compared with the Mg-1Mn-1Y-2.5Nd alloy. These differences in the tensile mechanical properties between the two alloys are mainly attributed to their different texture types and amount and distribution of the Mg24Y5 precipitates.The serration flow behavior is observed in the Mg-1Mn-1Y-2.5Nd alloy at 200℃,but does not occur in the Mg-1Mn-3.5Y alloy.The Mg-1Mn-3.5Y alloy shows the cleavage fracture mode,while the Mg-1Mn-1Y-2.5Nd alloy exhibits the dimple fracture mode.

提升机制动系统测速机接手改造

制动系统测速机接手在使用过程中经常断裂,影响提升机的正常运行,使用橡胶接手,在挤压和拉伸变形的情况下不断裂,提升机能够平稳运行,保证了矿井的正常生产。

Effects of Y on mechanical properties and damping capacity of ZK60 magnesium alloys

The microstructure,mechanical properties and damping capacity of ZK60-xY(x=0,1.5%,2.5%,4.0%,mass fraction) magnesium alloys were investigated by using the optical microscope(OM),X-ray diffractometer(XRD),universal tensile testing machine and dynamic mechanical analyzer(DMA).The mechanisms for damping capacity of referred alloys were discussed by Granato-Lücke theory.The results show that Y additions remarkably reduce grain size(the average grain size is 21.6,13.0,8.6 and 4.0μm,respectively),and the tensile properties are enhanced with grain refining(the yield tensile strength increases to 292 MPa from 210 MPa and ultimate tensile strength increases to 330 MPa from 315 MPa).For the ZK60-xY(x=0,1.5%,4.0%)alloys,the damping capacity decreases with the increase of Y content.However,for the ZK60-xY(x=2.5%)alloy,the damping capacity improves abnormally,which is possibly related to the formation of Mg3Y2Zn3(W)FCC phase in this alloy.

Effect of intermetallic compound thickness on anisotropy of Al/Cu honeycomb rods fabricated by hydrostatic extrusion process

The effect of intermetallic compound （IMC） thickness on the thermal and mechanical properties of Al/Cu honeycomb rods was investigated. The Al/Cu honeycomb rods were fabricated using repeated hydrostatic extrusions at 200 ℃. During the process, an IMC layer with 1μm in thickness was generated at the Al/Cu interface. Different IMC thicknesses were obtained by post-heat treatment at 420 ℃ for 0.5 to 2 h. The IMC thickness increased to 10.1μm. The IMC layers were identified as Al2Cu （θ）, AlCu （η2）, and Al4Cu9（γ1） phases. The thermal conductivities in the longitudinal direction and cross direction decreased by 11.9% （（268±4.8） to （236±4.4） W/（m·K）） and 10.4% （（210±3.2） to （188±2.8） W/（m＆#183;K））, respectively, with increasing IMC thickness. The ultimate tensile strength and elongation of the Al/Cu honeycomb rod are （103±8.4） MPa and （73±6.2）%, respectively. The ultimate tensile strength increased to （131±6.5） MPa until the IMC thickness reached 7.7μm. It subsequently decreased to （124±3.9） MPa until the IMC thickness reached 10.1μm. The elongation of the Al/Cu honeycomb rod then sharply decreased to （29±2.5）% with increasing IMC thickness.