改进预备热处理工艺提高单缸联合转子超声检测穿透性

结合经典的切断晶粒遗传理论,通过小试样研究结果对单缸机组大直径高低压联合转子的预备热处理工艺进行改进,从晶粒细化的角度出发,消除杂波,解决了转子预备热处理后超声检测可探性偏低的问题。     

Effects of grain refinement on mechanical properties and microstructures of AZ31 alloy

Cerium was added in AZ31 alloy with the contents of 0.4%,0.8%and 1.2%respectively to produce experimental alloys. The grain refinement of Ce in the as-cast and rolled AZ31 alloy were studied by using Polyvar-MET optical microscope with a VSM2000 quantitative analysis system,KYKY2000 SEM and Tecnai G~2 20 TEM.And the mechanical properties of AZ31+Ce alloy were tested on a CSS-44100 testing system with computerized data acquisition.The results show that the cerium has a good grain refinement effect on the ...     

AZ31镁合金挤压薄板织构及力学各向异性

研究AZ31镁合金挤压薄板的显微组织、织构及室温下板面内各不同方向的力学性能。织构分析表明,挤压薄板主要有{0002}<1-010>和{10-10}<11-20>2种织构组分。拉伸测试结果显示,沿挤压方向屈服强度最高,达到200.4MPa,这是由于这种取向基面滑移和{1-012}锥面孪生均不能开动,发生织构强化的结果;与挤压方向呈45°方向伸长率最高达19.0%,这是由于具有{10-10}<11-20>织构组分晶粒的基面滑移开动;与挤压方向呈90°方向屈服强度最低仅为挤压方向相应值的一半左右,这是由于具有{10-10}<11-20>织构组分晶粒发生了{10-12}锥面孪生。     

超超临界机组用FB2转子中心检测密集缺陷原因分析

通过金相、扫描电镜等分析手段详细研究了FB2转子中心超声检测密集缺陷部位微观组织及夹杂物情况,明确了大尺寸复合型夹杂物周围伴生的其它冶金缺陷及在锻造过程中产生的微裂纹(长度在200μm~300μm甚至更长)是导致3 mm及以上当量的密集缺陷的直接原因。     

Plastic deformation behavior of ZK60 magnesium alloy with addition of neodymium

The hot deformation simulation of a ZK60 magnesiuln alloy at different temperatures from 373 to 673 K and different strain rates of 0.1, 0.01 and 0.002 s^-1 was studied by using the Gleebe-1500 simulator. The plastic deformation behavior was measured and the deformation activation energy was calculated. The microstructures of ZK60 magnesium alloy with an addition of neodymium during the deformation process were observed by using Polyvar-MET optical microscope and Tecnai G^2 20 TEM. The results show that the working hardening, the dynamic recovery and the dynamic recrystallization occur during the plastic deformation process at different temperatures and strain rates. The dynamic recrystallization starts when the temperature is over 473 K and the DRX grain size after hot deformation is only 5-10 μm. So the refined grains improve both the tensile strength and the elongation of alloys at room temperature. Neodymium is added into the alloy and a precipitate phase Mg12Nd that impedes the movement of dislocations is formed, which benefits to increasing mechanical properties of ZK60 magnesium alloy.     

(Φ)1835mm低压转子锻件正火空冷过程温度场和应力场的计算机模拟

采用一重和清华大学合作开发的热处理模拟软件分析了φ1 835 mm低压转子锻件在正火空冷过程中温度场和应力场的变化情况.综合考虑相变与温度的耦合关系、相变潜热的影响和热物性参数的非线性等问题,获得了锻件1/4截面上温度场和应力场的变化云图,为工艺优化提供理论依据.     

1Mn18Cr18N护环钢固溶强化研究

1Mn18Cr18N护环钢热处理过程中不发生相变,是单项奥氏体,所以锻造时产生的碳化物只能通过固溶处理进入奥氏体。利用小试样模拟试验,在1050℃进行固溶处理,通过三种不同冷却方式分析其对力学性能、组织、析出物的影响,得出在水冷(水循环良好)条件下的综合力学性能良好,兼具较低的屈服强度和较好的韧性。     

Texture evolution of extruded AZ31 magnesium alloy sheets

The evolution of texture during the annealing and hot rolling process of extruded AZ31 magnesium alloy sheets was studied. There are two kinds of texture components in the extruded AZ31 sheets. One is {0002}<1-010> and the other is {1-010}<1-120>. The {0002}<1-010>component predominates. After annealing at 723 K for 3 h, both {0002}<1-010> and {1-010}<1-120> components are strengthened moderately. This indicates that grains with both two components mentioned above grow faster than those with other orientations. The {1-010}<1-120> component disappears and the intensity of {0002}<1-010> component decreases significantly after hot rolling with a 30% reduction at 623 K. This is mainly attributed to rotational dynamic recrystallization (RDX) during the hot rolling.     

Mn18Cr18N钢护环热锻研究

通过热压缩模拟试验,对Mn18Cr18N钢的高温热塑性进行了研究,对应力-应变曲线进行了测定,对护环热锻工艺过程进行了数值模拟。结果表明:在护环钢锭的初锻期,应变速率应尽量小,压下慢;马杠扩孔和芯棒拔长时应控制压下量。