scholarly journals Isothermal forging of Waspaloy in air with a new die material.

1988 ◽  
Vol 28 (11) ◽  
pp. 958-964 ◽  
Author(s):  
Takehiro OHNO ◽  
Rikizo WATANABE ◽  
Tsuyoshi FUKUI ◽  
Kohichi TANAKA
Keyword(s):  
Isothermal Forging ◽  
Die Material

Effect of Ta on the Oxidation Resistance of a Cast Nickel-Base Die Material with Low Cr and High W Content

2005 ◽  
Vol 475-479 ◽  
pp. 669-672
Author(s):  
Qing Li ◽  
Cheng Bo Xiao ◽  
Jin Xia Song ◽  
Ding Gang Wang ◽  
Ya Fang Han
Keyword(s):  
Oxidation Resistance ◽  
Protective Layer ◽  
Mass Gain ◽  
Nickel Base Superalloy ◽  
Temperature Oxidation ◽  
Isothermal Forging ◽  
Oxidation Test ◽  
Die Material ◽  
Nickel Base ◽  
Forging Die

A conventional cast nickel-base superalloy with the chemical composition of Ni-16W-2Mo-1.5Cr-6Al wt % has been recently developed as isothermal forging die material operating at temperatures above 1000°C. The oxidation test results showed that the oxide scale spalled heavily after exposure in air at 1050°C for 100 h, which is unacceptable for the process of isothermal forging. To improve the high temperature oxidation resistance, 3 wt% Ta was added into the alloy. Specimens after oxidation test were analyzed by the scanning electron microscope (SEM) and the X-ray diffraction analysis (XRD). The results showed that the oxides were mainly NiO, NiWO4, and NiAl2O4 for all the samples. The oxidation resistance of the alloy with 3wt%Ta was fairly good at 1050°C with the mass gain rate of around 0.016g/m2•h and spallation of oxides less than 2g/m2 within 100h.The SEM results showed that a continuous protective layer of Al2O3 has been formed under the layer of NiO for the alloy containing Ta.

Finite Element Simulation of Superplastic Isothermal Forging Process for Nickel-Base PM Superalloy

2007 ◽  
Vol 551-552 ◽  
pp. 297-302 ◽  
Author(s):  
Q.H. Li ◽  
Fu Guo Li ◽  
Q. Wan ◽  
Miao Quan Li
Keyword(s):  
Finite Element ◽  
Equivalent Stress ◽  
Turbine Disk ◽  
Cavity Surface ◽  
Yield Limit ◽  
Isothermal Forging ◽  
Forging Process ◽  
Die Material ◽  
Nickel Base ◽  
Pm Superalloy

The Chinese nickel-base powder metallurgy (PM) superalloy FGH96, which was processed through hot isostatic pressing, is very difficult to deform. FGH96 superalloy has better superplasticity in special deformation conditions and superplastic isothermal forging is the best formation method at present. The accurate constitutive equations of the FGH96 alloy was established depended on the isothermal compression experiments. A two dimensional and thermomechanical coupled axisymmetric finite element(FE) model in which both part and die were taken in consideration was established to fully simulate the FGH96 superalloy turbine disk superplastic isothermal forging process. Some physical parameters about the turbine disk forging process, such as load, stress field and strain field were calculated at different temperature within the forging range of FGH96. The regularity of peak equivalent stress acted on die cavity surface, yield limit and ultimate strength of die material during the forging process was found. Based on the regulation, peak equivalent stress acted on cavity surface must be extremely less than yield limit of die material, the optimized processing parameter 1050°C that is the best deformation temperature for the alloy was determined. That was proved better in practice and high quality disk was forged.

scholarly journals Development of a Die Material for Isothermal Forging of Superalloys in Air

1987 ◽  
Vol 27 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Takehiro OHNO ◽  
Rikixo WATANABE ◽  
Toshiaki NONOMURA
Keyword(s):  
Isothermal Forging ◽  
Die Material

scholarly journals Microstructural Evolution and Refinement Mechanism of a Beta–Gamma TiAl-Based Alloy during Multidirectional Isothermal Forging

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2496 ◽  
Author(s):  
Kai Zhu ◽  
Shoujiang Qu ◽  
Aihan Feng ◽  
Jingli Sun ◽  
Jun Shen
Keyword(s):  
Dynamic Recrystallization ◽  
Microstructural Evolution ◽  
Lamellar Microstructure ◽  
Phase Region ◽  
Second Step ◽  
Electron Backscattered Diffraction ◽  
Isothermal Forging ◽  
Continuous Dynamic Recrystallization ◽  
Mixture Phase ◽  
Refinement Mechanism

Multidirectional isothermal forging (MDIF) was used on a Ti-44Al-4Nb-1.5Cr-0.5Mo-0.2B (at. %) alloy to obtain a crack-free pancake. The microstructural evolution, such as dynamic recovery and recrystallization behavior, were investigated using electron backscattered diffraction and transmission electron microscopy methods. The MDIF broke down the initial near-lamellar microstructure and produced a refined and homogeneous duplex microstructure. γ grains were effectively refined from 3.6 μm to 1.6 μm after the second step of isothermal forging. The ultimate tensile strength at ambient temperature and the elongation at 800 °C increased significantly after isothermal forging. β/B2→α2 transition occurred during intermediate annealing, and α2 + γ→β/B2 transition occurred during the second step of isothermal forging. The refinement mechanism of the first-step isothermal forging process involved the conversion of the lamellar structure and discontinuous dynamic recrystallization (DDRX) of γ grains in the original mixture-phase region. The lamellar conversion included continuous dynamic recrystallization and DDRX of the γ laths and bugling of the γ phase. DDRX behavior of γ grains dominated the refinement mechanism of the second step of isothermal forging.

A Multi-Level Low Cycle Fatigue Damage Model for Forging Die Material

2006 ◽  
Vol 514-516 ◽  
pp. 804-809
Author(s):  
S. Gao ◽  
Ewald Werner
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Die Material ◽  
Multi Level ◽  
Loading Sequence ◽  
Forging Die

The forging die material, a high strength steel designated W513 is considered in this paper. A fatigue damage model, based on thermodynamics and continuum damage mechanics, is constructed in which both the previous damage and the loading sequence are considered. The unknown material parameters in the model are identified from low cycle fatigue tests. Damage evolution under multi-level fatigue loading is investigated. The results show that the fatigue life is closely related to the loading sequence. The fatigue life of the materials with low fatigue loading first followed by high fatigue loading is longer than that for the reversed loading sequence.

The Effect of Isothermal Forging Process Parameters on the Microstructure and the Properties of TA15 Near α Titanium Alloy

2007 ◽  
Vol 26-28 ◽  
pp. 367-371
Author(s):  
Hong Zhen Guo ◽  
Zhang Long Zhao ◽  
Bin Wang ◽  
Ze Kun Yao ◽  
Ying Ying Liu
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Tensile Properties ◽  
Process Parameters ◽  
Spherical Shape ◽  
Deformation Degree ◽  
Isothermal Forging ◽  
Forging Process ◽  
Α Phase ◽  
Strip Shape

In this paper the effect of isothermal forging process parameters on the microstructure and the mechanical properties of TA15 titanium alloy was researched. The results of the tests indicate that, in the range of temperature of 850 °C~980 °C and deformation degree of 20%~60%, with the increase of temperature or deformation, as the reinforcement of deformation recrystallization, the primary α-phase tends to the spherical shape and secondary α-phase transforms from the acicular shape to fine and spherical shape with disperse distribution, which enhance the tensile properties at room and high temperature. With the increment of forging times, the spheroidization of primary α-phase aggrandizes and secondary α-phase transforms from spherical and acicular shape to wide strip shape, which decrease the tensile properties at room and high temperature. The preferable isothermal forging process parameters are temperature of 980 °C, deformation degree of 60%, and few forging times.

Influences of Sintering Process on the Microstructure and Mechanical Behavior of ZrO2 Nano-Composite Ceramic Tool and Die Material

2010 ◽  
Vol 154-155 ◽  
pp. 1356-1360 ◽  
Author(s):  
Ming Dong Yi ◽  
Chong Hai Xu ◽  
Jing Jie Zhang ◽  
Zhen Yu Jiang
Keyword(s):  
Mechanical Properties ◽  
Ceramic Material ◽  
Composite Ceramic ◽  
Sintering Process ◽  
Ceramic Tool ◽  
Nano Composite ◽  
Pure Zro2 ◽  
Die Materials ◽  
Die Material ◽  
Composite Ceramic Material

A new ZrO2 nano-composite ceramic tool and die material was prepared with vacuum hot pressing technique. The effects of sintering parameters on the nano-composite ceramic tool and die materials were studied. The results indicated that the mechanical properties of ZrO2 nano-composite ceramic tool and die material with the additions of TiB2 and Al2O3 are higher than that of the pure ZrO2 ceramic material. Sintering at 1100 for 120min could improve the density and mechanical properties of ZrO2 nano-composite ceramic material. The flexural strength, fracture toughness and hardness with the optimum sintering parameters can reach 878MPa, 9.54MPa•m1/2 and 13.48GPa, respectively, obviously higher than that with non-optimum sintering parameters.

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