scholarly journals Taguchi Design for Heat Treatment of Rene 65 Components

2019 ◽  
Author(s):  
Christina Maria Katsari ◽  
Stephen Yue ◽  
Andrew Wessman
Keyword(s):  
Heat Treatment ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
Hold Time ◽  
Turbine Blades ◽  
High Strength ◽  
Gamma Prime ◽  
Nickel Based Superalloy ◽  
Hold Temperature ◽  
Microhardness Testing

Abstract Rene 65 is a nickel-based superalloy used in aerospace components such as turbine blades and disks. The microstructure in the as received condition of the superalloy consists of ~40% volume fraction of gamma prime precipitates, which gives such a high strength that thermomechanical processing is problematic. The goal of this study was to develop a heat treatment for manufacturing of Rene 65 components by changing the size distribution and volume fraction of those precipitates and lowering the strength. Gamma prime in this alloy is observed in three sizes, ranging from a few μm to tens of nm. For the design of the heat treatments, Design of Experiments (DOE) has been used; more specifically Taguchi’s L8 matrix. The four factors that are examined are cooling rate, hold temperature, hold time and cooling method to room temperature. The levels of the factors were two (high and low) with replication. Microstructures were characterized by Scanning Electron Microscopy and mechanical properties by Vickers microhardness testing.

Long-Term Gamma Prime Phase Stability after Various Heat Treatment Conditions with Temperature Dropping during Solution Treatment in Cast Nickel Base Superalloy, Grade Inconel-738

2017 ◽  
Vol 891 ◽  
pp. 420-425
Author(s):  
Sureerat Polsilapa ◽  
Aimamorn Promboopha ◽  
Panyawat Wangyao
Keyword(s):  
Heat Treatment ◽  
Turbine Blades ◽  
Solution Treatment ◽  
Nickel Base Superalloy ◽  
Gamma Prime ◽  
Nickel Based Superalloy ◽  
Treatment Conditions ◽  
Nickel Base ◽  
Base Superalloy

Cast nickel based superalloy, Grade Inconel 738, is a material for turbine blades. Its rejuvenation heat treatment usually consist of solution treatment condition with temperature range of 1125-1205 oC for 2-6 hours. Then it is following with double aging process including primary aging at 1055oC for 1 hour and secondary aging at 845oC for 24 hours. However, the various selected temperature dropping program were performed during solution treatment to simulate the possible error of heating furnace. The maximum number of temperature dropping during solution treatment is varied from 1-3 times From all obtained results, the various temperature dropping during solution treatment conditions showed extremely the significant effect on the final rejuvenated microstructures and long-term gamma prime stability after heating at temperature of 900oC for 200 hours.

Microstructure and Tensile Properties of TRIP-Aided Steel Sheet Subjected to Hot-Rolling and Austempering

2021 ◽  
Vol 1016 ◽  
pp. 732-737
Author(s):  
Junya Kobayashi ◽  
Hiroto Sawayama ◽  
Naoya Kakefuda ◽  
Goroh Itoh ◽  
Shigeru Kuraoto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hot Rolling ◽  
Manufacturing Process ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Isothermal Holding ◽  
High Strength ◽  
Isothermal Transformation ◽  
Transformation Process ◽  
Steel Sheets

Various high strength steel sheets for weight reduction and safety improvement of vehicles have been developed. TRIP-aided steel with transformation induced plasticity of the retained austenite has high strength and ductility. Conventional TRIP-aided steels are subjected to austempering process after austenitizing. Generally, elongation and formability of TRIP-aided steel are improved by finely dispersed retained austenite in BCC phase matrix. The finely dispersed retained austenite and grain refinement of TRIP-aided steel can be achieved by hot rolling with heat treatment. Therefore, the improvement of mechanical properties of TRIP-aided steel is expected from the manufacturing process with hot rolling and then isothermal transformation process. In this study, thermomechanical heat treatment is performed by combining hot rolling and isothermal holding as the manufacturing process of TRIP-aided steel sheets. The complex phase matrix is obtained by hot rolling and then isothermal holding. Although the hardness of the hot rolled and isothermal held TRIP-aided steel is decreased, the volume fraction of retained austenite is increased.

The effect of heat treatment on characteristics of the gamma prime phase and hardness of the nickel-based superalloy Rene®80

2019 ◽  
Vol 227 ◽  
pp. 46-55 ◽  
Author(s):  
Mohammad Mehdi Barjesteh ◽  
Seyed Mehdi Abbasi ◽  
Karim Zangeneh Madar ◽  
Kourosh Shirvani
Keyword(s):  
Heat Treatment ◽  
Gamma Prime ◽  
Nickel Based Superalloy ◽  
Prime Phase

Effects of Heat Treatment on Microstructure of High-Strength Manganese-Silicon Steels

2017 ◽  
Vol 270 ◽  
pp. 239-245
Author(s):  
Dagmar Bublíková ◽  
Štěpán Jeníček ◽  
Kateřina Opatová ◽  
Bohuslav Mašek
Keyword(s):  
Heat Treatment ◽  
Cooling Rate ◽  
Microstructure Evolution ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength ◽  
Quenching And Partitioning ◽  
Alloying Additions ◽  
New Procedures ◽  
Strength And Ductility

Today’s advanced steels are required to possess high strength and ductility. This can be accomplished by producing appropriate microstructures with a certain volume fraction of retained austenite. The resulting microstructure depends on material’s heat treatment and alloying. High ultimate strengths and sufficient elongation levels can be obtained by various methods, including quenching and partitioning (Q&P process). The present paper introduces new procedures aimed at simplifying this process with the use of material-technological modelling. Three experimental steels have been made and cast for this investigation, whose main alloying additions were manganese, silicon, chromium, molybdenum and nickel. The purpose of manganese addition was to depress the Ms and Mf temperatures. The Q&P process was carried out in a thermomechanical simulator for better and easier control. The heat treatment parameters were varied between the sequences and their effect on microstructure evolution was evaluated. They included the cooling rate, partitioning temperature and time at partitioning temperature. Microstructures including martensite with strength levels of more than 2000 MPa and elongation of 10–15 % were obtained.

Finite Element Simulation and Optimisation of Ageing Precipitation in Nickel Base Superalloys with a Low Gamma-Prime (g’) Volume Fraction

2011 ◽  
Vol 172-174 ◽  
pp. 881-886 ◽  
Author(s):  
Franck Tancret ◽  
Philippe Guillemet ◽  
Florent Fournier Dit Chabert ◽  
René Le Gall ◽  
Jean François Castagné
Keyword(s):  
Heat Treatment ◽  
Finite Element ◽  
Volume Fraction ◽  
Nucleation And Growth ◽  
Thermodynamic Quantities ◽  
Gamma Prime ◽  
The Matrix ◽  
Element Approach ◽  
Automatic Heat ◽  
Nickel Base

A finite element approach is used to simulate the precipitation of Ni3(Al,Ti) intermetallics in nickel-based superalloys containing a low volume fraction of spherical g’ precipitates, in which precipitation occurs following nucleation and growth mechanisms. Classical differential equations of nucleation and growth are implemented in the software Comsol (formerly Femlab), to compute the number of precipitates per unit volume and their mean size. Another originality of the model is the use of thermodynamic quantities coming from phase diagram computations (Thermo-Calc), like the temperature variation of the equilibrium g’ volume fraction, and the evolution of the concentration of g’ forming elements (Al, Ti) in the matrix with the volume fraction of precipitates. Once adjusted to experiment in the case of isothermal ageings, the model can be used to simulate precipitation during complex thermal histories. Finally, automatic heat treatment optimisation procedures are proposed and tested, which can reduce heat treatment times by a factor of more than five.

Transformation Induced Plasticity (TRIP) Effect Used in Forming of Carbon CMnSi Steel

2005 ◽  
Vol 500-501 ◽  
pp. 461-470 ◽  
Author(s):  
Jiří Kliber ◽  
Bohuslav Mašek ◽  
Ondrej Zacek ◽  
H. Staňková
Keyword(s):  
Continuous Casting ◽  
Hot Rolling ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
High Strength ◽  
Ferrite Matrix ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Forming Temperature

Transformation induced plasticity (TRIP) steel combines high strength and high ductility that makes it particularly suitable for forming. Martensite within a ferrite matrix is usually obtained either by continuous casting of slabs followed by hot rolling (which is the fastest method, hence the most economical one, producing, however, relatively thick products) or by the continuous casting of slabs followed by hot rolling, cold rolling and annealing (the method used for thin products). High cooling rates, low coiling temperatures and low reduction during hot deformation were generally found to suppress the formation of polygonal ferrite and promote the presence of retained austenite. This paper focuses on development and modifications of two CMnSi-based TRIP steels with 0,23 % C;1,4 % Mn; 1,9 % Si; ( 0,08 % Nb) by means of laboratory thermomechanical processing. Description of experimental devices for the analysis of transformation plasticity under tensioncompression loading is given. Experiments were carried out on the simulator for thermaldeformation cycles SMITWELD and TANDEM was used for thermomechanical processing on the laboratory rolling mill. The maximum volume fraction of retained austenite and the resulting optimum combination of tensile strength and ductility were achieved in testing heats. Special attention was paid to volume fraction changes of single phases and to changes in morphology of phases. The results suggest that rather short isothermal bainite transformation times are sufficient to obtain TRIP microstructure. The influence of parameters of thermomechanical processing such as the amount of strain, forming temperature and austenitization time and temperature on microstructures of TRIP steels were evaluated.

scholarly journals High Versatility of Niobium Alloyed AHSS

2017 ◽  
Vol 62 (3) ◽  
pp. 1485-1491 ◽  
Author(s):  
L. Kučerová ◽  
K. Opatová ◽  
J. Káňa ◽  
H. Jirková
Keyword(s):  
Heat Treatment ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength ◽  
Processing Parameters ◽  
High Ductility ◽  
Processing Strategies ◽  
Cooling Schedules ◽  
Final Microstructure ◽  
Steel Processing

AbstractThe effect of processing parameters on the final microstructure and properties of advanced high strength CMnSiNb steel was investigated. Several processing strategies with various numbers of deformation steps and various cooling schedules were carried out, namely heat treatment without deformation, conventional quenching and TRIP steel processing with bainitic hold or continuous cooling. Obtained multiphase microstructures consisted of the mixture of ferrite, bainite, retained austenite and M-A constituent. They possessed ultimate tensile strength in the range of 780-970 MPa with high ductility A5mmabove 30%. Volume fraction of retained austenite was for all the samples around 13%. The only exception was reference quenched sample with the highest strength 1186 MPa, lowest ductility A5mm= 20% and only 4% of retained austenite.

The Effect of Post-heat Treatment on the Microstructures of Single Crystal DD6 Superalloy

2016 ◽  
Vol 35 (8) ◽  
pp. 751-760
Author(s):  
Dongfan Li ◽  
Hangshan Gao ◽  
Zhixun Wen ◽  
Zhenwei Li ◽  
Zhufeng Yue
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Volume Fraction ◽  
Ageing Time ◽  
Thermal Cycles ◽  
Quenching Temperature ◽  
Gamma Prime ◽  
Precipitation Processes ◽  
Temperature Transformation ◽  
Equilibrium Volume Fraction

AbstractVarious thermal cycles at the end of solution heat treatment and their influences on microstructure of single crystal superalloy DD6 were studied by experiments. During various thermal cycles, the qualitative and quantitative microstructure of samples quenched of the transformations is microscopically characterized. This completely includes the large changes in volume fraction, size distribution and morphology of gamma prime precipitate experienced in the upper temperature transformation. Noticeable deviation from the equilibrium volume fraction of γ’ phase is detected in both the dissolution and precipitation processes above 1,120°C for both moderate cooling and heating rate; differences were mainly attributed to the unsteady nature of the turbulent flow. The growth and alignment of the γ’ precipitates are deeply influenced by several factors, e.g. ageing time, cooling rate and quenching temperature. In addition, interesting findings such as “labyrinth” and “cluster” morphologies were observed by scanning electron microscope. During precipitation processes, the complicated microstructure evolution is illustrated by considering the consecutive equilibrium shapes of a coherent precipitate, which grows under the interaction with its neighbors and the coherency of the precipitates improves their potential to resist dissolution.

Enhancement of Microstructural and Hardness Properties of Commercially Pure Titanium (Ti-0.5Zn) by Thermomechanical Processing

2013 ◽  
Vol 824 ◽  
pp. 275-282 ◽  
Author(s):  
Oluwagbenga T. Johnson ◽  
Olayinka O. Awopetu ◽  
Olurotimi A. Dahunsi
Keyword(s):  
Heat Treatment ◽  
Thermomechanical Processing ◽  
Density Ratio ◽  
Pure Titanium ◽  
High Strength ◽  
Commercially Pure Titanium ◽  
Β Phase ◽  
Commercially Pure ◽  
Hardness Property ◽  
Equiaxed Grains

Titanium alloys are widely used in the aerospace, biotechnology, automotive, energy, marine industrial constructions and components due to their high strength-to-density ratio, excellent fatigue/crack propagation behaviour and corrosion resistance. This study investigates the αβ phase transformation which Ti-0.5Zn alloy undergoes on being subjected to heat treatment with the aim of improving its properties and to enhance its industrial application. The β phase, with Widmatansttäten type growth was produced by heat treatment of the alloy in the temperature range of 800°C to 1000°C. The resultant microstructure and hardness of the alloy was also investigated. The result showed improved morphology evidenced by transformation from the equiaxed grains to more lamellar structures in the samples. Hardness property improved by 20% too.

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