GH4169合金涡轮盘锻件粗晶质量分析和控制

通过分析GH4169合金涡轮盘不同部位的成形特点及合金特性,提出了对粗大合金组织的有效预防措施和改善方法,为确保锻件冶金质量,提高质量稳定性提供了有益参考。     

GH4169高温合金惯性摩擦焊的有限元模拟

基于Ansys有限元分析软件,建立了GH4169高温合金惯性摩擦焊过程的二维模型,进行了热力耦合分析,得到了焊接过程中的瞬时温度场和应力应变场,获得了焊接缩短量。根据惯性摩擦焊工艺分析了温度场和应力应变场的形成过程。     

基于正交试验法的GH4169高速铣削表面粗糙度研究

对镍基合金GH4169试件高速铣削加工表面粗糙度进行了正交试验,运用极差分析法得出4个试验因素对表面粗糙度影响程度的不同,可绘制铣削参数对表面粗糙度的影响趋势曲线,并对其影响原因进行了分析。     

Absorption effect of pure nickel on the corrosion behaviors of the GH3535 alloy in tellurium vapor

In this study,pure Ni was demonstrated to pro-tect the GH3535 alloy from Te vapor corrosion because of its strong absorption capacity.Severe Te corrosion of a single GH3535 alloy sample occurred in Te vapor at 700℃,which manifested as complex surface corrosion products and deep intergranular cracks.However,when pure Ni and the GH3535 alloy were put together in the vessel,the GH3535 alloy was completely protected from Te corrosion at the expense of the pure Ni.Thermody-namic calculations proved that the preferential reaction between pure Ni and Te vapor reduced the activity of Te vapor considerably,preventing the corrosion of the GH3535 alloy.Our study reveals one potential approach for protecting the alloys used in molten-salt reactors from Te corrosion.     

GH163缝焊结合线伸入问题的研究

镍基高温合金GH163在进行电阻缝焊过程中,常见的缺陷就是结合线伸人.结合线伸人容易引起应力集中,减小了熔核的实际有效直径,在焊件承受动载荷时,有可能发展成为裂纹,引起接头的破坏.因此,弄清其形成原因和机理对预防结合线伸人的形成十分必要.本文通过对GH163的电阻缝焊试验和对结合线部位的元素成分分析,确定了结合线伸入的形成原因,并分析了其形成机理.为解决高温合金电阻缝焊过程中结合线伸人问题提供了理论依据.     

Performance of ceramic tools in high-speed cutting iron-based superalloys

A series of turning tests were conducted to investigate the cutting performance of ceramic tools in high-speed turning iron-based superalloys GH2132 (A286). Three kinds of ceramic tools, KY1540, CC650, and CC670 were used and their materials are Sialon, Al₂O₃–Ti(C,N), and Al₂O₃–SiC_w, respectively. The cutting forces, cutting temperatures, tool wear morphologies, and tool failure mechanisms are discussed. The experimental results show that with the increase in cutting speed, the resultant cutting forces with KY1540 and CC670 tools show a tendency to increase first and then decrease while those for CC650 increase gradually. The cutting temperature increases monotonically with the increase in cutting speed. The optimum cutting speeds for KY1540 and CC650 when turning GH2132 are less than 100 m/min, while those for CC670 are between 100 and 200 m/min. Flank wear is the main reason that leads to tool failure of KY1540 and CC670 while notch wear is the main factor that leads to tool failure of CC650. Tool failure mechanisms of ceramic tools when machining GH2132 include adhesion, chipping, abrasion, and notching. Better surface roughness can be got using CC670 ceramic tools.     

EFFECTS OF MICROSTRVCTURE ON FATIGUE CRACK GROWTH BEHMIOR IN Ni-BASE SUPERALLOY GH586

1.IntroductionInmetalsandalloys,thenearthresholdfatiguecrackgrowthisfrequentlytermed'microstructurallysensitive'.Thisisduebothtotheappearanceofthefracturesllrface,whichisoftenfaceted,andtotilelargevariationsincrackgrowthratewhichcanbeobtainedbyalteringparameterssllchasgrainsize,yieldstrength,ortherelativeproportionsanddistributionsofphasesinthemicrostructure[1].Thisimpliesthatsignificantimprotremelltintotalfatiguelifecouldbeachievedbychangingthemicrostructureofalloys.Therefore,itwouldbeveryadv…     

A New Strategy for Restraining Dynamic Strain Aging in GH4169 Alloy During Tensile Deformation at High Temperature

The dynamic strain aging(DSA) behavior was investigated in GH4169 alloy during tensile deforming with electric-pulse current(EPC) at 750 ℃.The results show that DSA is restrained in the alloy when deformed with 40 Hz-EPC.The size ofγ " phase inner grains increases obviously and δ phase is facilitated to precipitate on grain boundary in the alloy applied with EPC,due to the promotion effect of EPC on the diffusion and segregation of atoms.Transmission electron microscopy(TEM)results indicate that...     

固溶冷却方式对GH4220合金螺栓力学性能的影响

将GH4220合金螺栓在1220 ℃固溶处理冷却阶段的冷却方式由标准热处理制度的空冷改为缓慢冷却(24 min冷却至1100 ℃保温1 min,之后空冷),利用SEM、微机控制电子万能试验机观察合金的晶界形态及力学性能的变化。结果表明,相比标准热处理制度,缓慢冷却处理以后,晶界锯齿状特征明显,晶界由平直晶界变为弯曲晶界。室温抗拉强度由标准热处理制度的1004 MPa提升至1143 MPa,提高了13.8%,950 ℃高温抗拉强度由标准热处理制度的478 MPa提升至532 MPa,提高了11.3%;940 ℃高温应力持久断裂时间提升尤为明显,由标准热处理制度的38.2 h提高到51.7 h,提高了35%。     

断口附近组织对GH4080A合金缺口持久性能的影响

本文以630 ℃汽轮机紧固件备选合金GH4080A合金为研究对象,对美国Special Metals和抚顺特钢冶炼的材料经过标准热处理后分别在不同载荷下进行高温缺口持久实验,并结合光学显微镜(OM)和扫描电镜(SEM)及背散射电子衍射(EBSD)分析,研究合金持久寿命的分散性与持久样品断口附近组织的关联性。结果表明：GH4080A抚钢边缘和芯部持久寿命不同的主要原因是两者晶粒大小不同;抚钢边缘与SMC边缘持久寿命不同的主要原因是两者变形机制不同,前者为晶界滑移,后者为晶内变形与晶界变形协调作用。