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Mechanical Properties in Hot Forged Steel Parts in Relation to Properties in Corresponding Parts made by Casting Solely Henry Valberg1, a*, Morten Langøy2,b and Mette Nedreberg3,c 1Norwegian University of Science and Technology, Department of Engineering Design and Materials, Richard Birkelands v. 2b, 7491 Trondheim, Norway 2University of Stavanger, Department of Mechanical and Structural Engineering and Material Science, 4036 Stavanger, Norway 3Rolls-Royce Marine AS, Propulsion-Ulsteinvik, Norway ahenry.valberg@ntnu.no, bmorten.langoy@uis.no, cmette.nedreberg@rolls-royce.com Keywords: Hot forging of steel, Cast steels, Mechanical testing, Mechanical tests, Bending test, “Eye”-shaped bend specimen, Microstructural defects.
It is a common understanding that hot forging will improve the properties of a steel part in relation to what is the result when the same part is made by casting solely.
For instance, it has been shown in a number of articles [1-4] how the presence of casting defects either as micro, or macro porosity, affects the fatigue life of steel castings.
To identify important process factors in the hot forming operation when forging this component from an initial workpiece of cylindrical shape, a 3D FE-model was made of the process.
For large surface roughness it seems that the roughness will be a factor that determines when the specimen will start to break down.

Furthermore, without a coolant, titanium alloys are more susceptible to reacting with atmospheric gases which can also adversely affect their mechanical properties.
Table 2 shows the physical properties of the tested water-miscible cutting fluid at different concentration ratios.
The best combinations of the control factors for minimising the tool wear when turning Ti-6Al-4V are 10% fluid concentration, cutting speed of 58 m/min and feed rate of 0.1 mm/rev using uncoated carbide cutting tool H13A.
This can be ascribed to its superior combination of high hot hardness, toughness, and high transverse rupture strength properties [12].
A high regression value (R2 is above 99%) as well as very low model error (0.5%) indicates that all important factors are considered in this study.

The challenge is to relate the main and relevant parameters of the process (geometry of the tool, topologies of the assembly, others parameters such as axial force, torque, tool positioning, the nature of materials to be assembled,..) to the mechanical properties expected for that weld The study proposes an analogical simulation in a modeling clay (plasticine) workpieces environment.
Thus we will be able to deduce the mechanical characteristics of the weld"s behaviour
These zones are the stir zone, the thermo-mechanically affected zone (TMAZ) and the heated affected zone (HAZ)
However to facilitate the observation of mechanical phenomena on the physical simulation during the weld, a geometrical scale factor has to be chosen.
The final result will be the creation of a model of FSW for different materials with different kind of joining 5_References [1] NANDAN (R)-DEBROY (T)-BHADESHIA (H K D H) - Recent advances in Friction Stir Welding-Process,Weldment, Structure and properties - Progress in Materials Science 53 PP 980-1023 (2008) [2] BASTIER (A), Modélisation du soudage d'alliages d'aluminium par friction et malaxage, Thèse de doctorat de l'Ecole Polytechnique, décembre (2006) [3] GLUKHMAN (A.A.). - Introduction to the theory of similarity.

Design considerations of Electrostatic generator Throughout all the topologies, methods and models of the capacitive generators studied in the literature, the following factors are seen affecting the design of the generator: type of kinetic energy, the variable capacitor material type, capacitor geometrical factors, realization methods and the power processing.
Capacitor Geometrical Factors.
The size of variable capacitor in electrostatic generator is one of the most important factors affecting the power generation.
The three factors can be optimized by proper realization method that will be discussed in the next section.
These circuits are highly dependent on the output properties of the harvester: frequency, output voltage, current and power.

Therefore investigation the microstructure and piezoresistive properties of nc-Si:H thin films, including the gauge factor (GF) and temperature coefficient of resistance (TCR), is very meaningful and necessary for application.
Experimental set-up for piezoresistive properties evaluation.
Due to this unique electronic transport properties, electric properties of phosphorus-doped nc-Si:H thin films, including TCR, show good thermal stability.
Effects of high hydrogen dilution ratio on surface topography and mechanical properties of hydrogenated nanocrystalline silicon thin films.
Piezoresistive properties of polycrystalline silicon.

Das and co-workers fabricated two series of flexible PU foams by substituting petroleum-based polyol with increasing amount of soy-based polyol (SBP) having different hydroxyl numbers and their results showed that the morphology and mechanical properties of the foams were affected significantly by the foam fabrication method and SBP hydroxyl numbers [5].
This research was carried out to study the effect of palm oil-based polyol concentration on physical-mechanical properties and cellular structure of flexible PU foams.
High densities generally result in improved load-bearing properties [9].The support factor or SAG factor or compressive deflection coefficient is the ratio of 65% indentation force deflection (IFD) to the 25% IFD.
This factor can be used to indicate the cushioning quality; higher support factors indicate better cushioning quality [9].
Nevertheless, the support factors of all foams containing palm oil-based polyol were higher than that of reference foam indicating better cushioning quality.

The cambolt is used as a part in the steering system of a vehicle for the purpose of driving balanced, so some proper mechanical properties such as strength and endurance limit are required for this part.
Fu and Zhu[3] et al (2010) predicted the best conditional temperature of different forming processes for TA15 alloy bolt with excellent mechanical properties and presented a rational die design, but it also given the billet as a hot forging.
In general, the friction factor for cold forging ranges from 0.05 to 0.15; here, the shear friction factor between the workpiece and the dies is set equal to 0.08, which is specifically used for cold forging in DEFORM.
The physical properties of these materials are listed in Table 1.
The lifespans of the dies are affected by how much load they can withstand, and their relationships with the other variables.

Furtherly, it is held by scholars that it is the free gas and the adsorbed gas that coeffect to reduce the physical and mechanical properties of the coal and rock mass.
In order to examine how the friction characteristics of the crack affects the mechanical properties of coal containing gas, following steps will be done.
This is one of the reasons that coal physical and mechanical properties decreases after gas adsorption.
Test analysis of the mechanical properties of the coal containing gas.
The experiment research on the effect of gas on mechanical properties and mechanical response of coal.

The significant influence and the optimum condition achieved by analysis four factors and regression analysis.
In this report, the factors that affect finishing performance including DMDHEU, catalyst, baking temperature and time were investigated.
Results and Discussion The changes on fabric physical properties after treatment All samples were treated according to Central Composite Design for resin treatment and the change rates of fabric physical properties were recorded in table 1.
Table 2 The significance of each factors on change rate (%) of fabric properties after treatments Factors Significance (p) %∆W %∆Swarp %∆Sweft %∆WRA A 0.397 0.005 0.607 0.009 B 0.666 0.992 0.077 0.148 C 0.519 0.000 0.000 0.000 D 0.532 0.013 0.069 0.006 When p＜0.05, the effect is significantly and the p smaller, more significant.
Optimization of treatment Conditions According to all factors designed in table 1 and considered all data of physical properties change rate in table 2, their low, high and expectation values were set as shown in table 3.

a*rolando@cicy.mx, bsakai@mech.saitama-u.ac.jp, cwakayama@tmu.ac.jp Keywords: Acoustic emission, Non-destructive technique, Mechanical properties, Damage behavior.
Different inherent factors on composite materials system affects its mechanical behavior.
When the chemical interactions fibers/HDPE are higher due to its surface functionality imparted by the treatments, the composites also exhibited enhanced mechanical properties (Fig. 6).
By increasing the adhesion strength in the fiber/matrix interfacial zone and improving the cohesion chemically through the silane treatment, an enhancement in the mechanical properties were observed and detected by AE.
AE signal identification and correlation are particularly complex to achieve in fiber reinforced composites, where, in addition to anisotropic behavior, a large variability in fiber geometry and properties is also existing.