Forging Temperature Research Articles

Research of On-Line Large-Size Forging Measurement System Based on LabVIEW

Forging temperature is usually around 1000°C in free forging scene. Manual measurement leads to large measurement errors. Adopting the non-contact 3D scanning technology, make the laser beam sweep across the forging surface to get three-dimensional coordinates of the points on the forging surface in space. Neighboring scan points separate by less than 0.25mm. The measurement error is less than 6mm. The coordinate,s data are sent to the LabVIEW procedure. The procedure analyzes the coordinates to calculate the size of the large-size forging to realize automatic measurement of the forgings. The procedure can also reconstruct the image of the large-size forging. These make us detect the real-time changes of the forging far from the free forging scene.

Tensile properties and microstructure of Ti14 alloy after semi-solid forging

Tensile properties of a new α+Ti 2Cu alloy after solid forging at 950 °C and semi-solid forging at 1 000 °C and 1 050 °C were investigated over the temperature range of 20–600 °C. The results reveal that high strength and low ductility are obtained in all semi-solid forged alloys. Tensile properties decrease as the semi-solid forging temperature increases, and cleavage fractures are observed after semi-solid forging at 1 050 °C. The variations in tensile properties are attributed to the coarse microstructures obtained in the semi-solid alloys. It is found that the elevated semi-solid temperatures lead to more liquid precipitates along the prior grain boundaries, which increases the peritectic precipitation and formation of Ti 2Cu precipitation zones during re-solidification. Recrystallization heat treatment leads to fine microstructure of semi-solid forged alloys, resulting in improvement of tensile properties.

Grain boundary characteristics and tensile properties of Ti14 alloy after semi-solid deformation

The microstructure and room-temperature tensile properties of Ti14, a new α+Ti2Cu alloy, were investigated after conventional forging at 950°C and semi-solid forging at 1000 and 1050°C, respectively. Results show that coarse grains and grain boundaries are obtained in the semi-solid alloys. The coarse grain boundaries are attributed to Ti2Cu phase precipitations occurred on the grain boundaries during the solidification. It is found that more Ti2Cu phase precipitates on the grain boundaries at a higher semi-solid forging temperature, which forms precipitated zones and coarsens the grain boundaries. Tensile tests exhibit high strength and low ductility for the semi-solid forged alloys, especially after forging at 1000°C. Fracture analysis reveals the evidence of ductile failure mechanisms for the conventional forged alloy and cleavage fracture mechanisms for the alloy after semi-solid forging at 1050°C.

Friction factor evaluation by FEM and experiment for TA15 titanium alloy in isothermal forming process

The friction at die–workpiece interface is an important parameter in metal forming processes, which affects the metal flow, cavity fill, surface quality, etc. The friction in the forming process is influenced by material properties and forming conditions. The friction in forming process of TA15 (Ti–6Al–2Zr–1Mo–1V) titanium alloy under high temperatures (isothermal forming) and low strain rates is studied here by ring compression test. The friction calibration curves are elaborated by means of finite element method. The research on the calibration curves and friction factor at the loading speed v = 0.1–1.0 mm/s and the conventional forging temperature (950°C) and near-beta forging temperature (970°C) is carried out. The influence of loading speed on friction calibration curves is similar to the influence on friction factor m: at the low (m about 0.7) friction condition, the influence of loading speed can be ignored, however the influence is notable in the midst magnitude (about 0.2–0.5). The temperature variation from 950°C to 970°C has little influence on friction calibration curves, but has notable influence on m under lubricated condition.

Numerical Simulation and Experimental Study on Warm Forging Process of Half Axle Bevel Gear

According to the shape character of half axle bevel gear forging a process based on closed-die forging scheme was proposed. Based on a series of simulation the influence of initial forging temperature on forming force, the influence of web thickness and web position on stress, damage factor and forming force were analyzed. According to numerical analysis the web dimensions and forging temperature which ensure a minimum stress, a minimum damage factor and a proper forming load were achieved. The forming result was simulated and evaluated, and the forming load was controlled under 760ton. At last the research project got good test verifying.

Thermomechanical Load Study on FGM Clad Hot Forging Die under Mechanical Press

Hot forging die bear periodic thermal load and mechanical load during service, and bad work environment makes the service life of dies generally short. Hot forging die damages mainly appear in temperature fluctuation zone, and gradient composite materials cladding process can be used to do surface treatment on homogeneous hot forging die. This process can greatly decrease the peak value of temperature and stress and prolong the service life of hot forging die. FE model of hot forging process under mechanical press was build based on Deform-2D, temperature and stress field of homogeneous hot forging die and FGM surface cladding hot forging die under mechanical press were compared. Then the characters of thermomechanical load based on FGM surface cladding hot forging die were described, which provided foundation for design and manufacture of FGM hot forging die.

Process Parameters Optimization for Isothermal Forging of Ti-6Al-4V Alloy using Taguchi Method and Artificial Neural Network

Enabling and developing the required „Process‟ efficiency in an Input-Process-Output System, is bound to provide effective solutions for today‟s need for maximized production especially in dwindling Input conditions. Process optimization is a significant and contributing step towards such process efficiency as it paves way for improved overall productivity. The present work involves, an approach using soft computing paradigm for the process parameter optimization of multiple input single output isothermal forging of Ti-6Al-4V alloy. In this paper a combination of Taguchi‟s L27 Orthogonal Array (OA-L27) along with back- propagation artificial neural network and engineering optimization concepts to determine the optimal process parameter settings of forging temperature, strain rate and strain for the isothermal forging. The optimum solution is valid in the ranges of forging process parameters that were used for training the artificial neural network.

Thermal Deformation Behavior of 1Cr12Ni3Mo2VNbN Alloy and Its Application in the Blade Forging

Thermal deformation flow stress equation of 1Cr12Ni3Mo2VNbN in the temperature range of 980 °C~1180 °C is established by means of hot simulation test and the regression analysis. The results show that the data obtained accords with hyperbolic sine function and the equation will also enrich the material performance database. The established equation is used in the blade forging production based on numerical simulation technology, and the numerical simulation results show that utilizing flat head billet can solve the problem of filling dissatisfaction at the root of the blade. Adopting water-based graphite lubricant provides better lubrication condition for blade forging. The equipment wear and energy consumption can be reduced by applying initial forging temperature of 1130°C in the blade forging process. The application of thermal deformation flow stress equation and numerical simulation technology can reduce the number of trial production, shorten the process design cycle and improve production efficiency in a large extent.

Forgeability and die-forging forming of direct chill casting Mg–Nd–Zn–Zr magnesium alloy

Mg–3.0Nd–0.2Zn–0.4Zr (wt.%, NZ30K) is a newly developed magnesium rare earth alloy with middle strength and high toughness in as-cast state. In this paper the forgeability of the as-cast NZ30K alloy prepared by direct chill (DC) casting was studied. The forgeability of the DC casting NZ30K alloy was firstly modeled by using uniaxial tensile and compression tests at temperatures between 250 and 400 °C and strain rates ranging from 0.001 to 10 S −1. The results show that the optimum forging temperature of the as-cast NZ30K alloy is between 350 and 400 °C and strain rate ranges from 0.01 to 1 S −1. Finally, a flange of automobile clutch was tentatively and successfully forged by using the DC casting NZ30K billet. The forged flange possesses desired microstructure and high mechanical properties. The mechanical properties of the product are further enhanced by T5 heat treatment for precipitate strengthening. The maximum ultimate tensile strength, yield strength and elongation of the T5 state alloy are 323.5 MPa, 318.2 MPa and 11.2%, respectively. The creep strain rates for the NZ30K alloy are 2.0 × 10 −8 and 1.2 × 10 −7 at the 200 and 250 °C, respectively.

Effect of Delta Phase on the Hot Deformation Behaviour and Microstructural Evolution of Inconel 718

In order to investigate the influence of -phase precipitation during high temperature forging of Inconel 718, hot axi-symmetric compression tests have been performed on specimens with two distinct initial microstructures: i) as-received material containing a dense population of  precipates at grain boundaries and along intragranular slip planes, and ii) material solution-treated to dissolve the  phase. Results indicate that the presence of  leads to a slight increase in peak stress and a proportionately greater post-peak reduction in flow stress, as compared to solution-treated material. For both types of microstructure flow softening is associated with grain refinement, but in different ways: in -free material conventional dynamic recrystallisation leads to the formation of new grains, whereas the presence of plate-like  appears to cause the mechanical break-up and segmentation of prior grains.

Numerical Analysis on Precision Forging of 7A09 Aluminum Impeller

Numerical simulation and test forming of the isothermal precision forging of an impeller was carried out. The forming processes were simulated with DEFORM-3D to obtain the forming characteristics and metal flow pattern. It indicated that the impeller can be forged by the method of isothermal-forging, and the deforming process can be divided into 3 stages. The forming of blades was depended on the extrusion of materials. During the forming, uneven deformation was existed in the billet, especially in the field of the blade root. The forging load was increased rapidly during the later stage of the forming process, and the maximum forging load was about 2961kN. According to the simulations, the die structure and the billet dimension were determined, the forging die was designed and manufactured, and the precision forgings of the impeller were produced successfully. Both of the simulation and the test forming indicated that the impeller forging could be performed with the assembled structure die and the isothermal extruding forming style satisfactorily. The ideal parameters to produce the precision forgings of the impeller are: a forging temperature of 450°C and a punch speed of 1mm/s. Under these conditions, the forgings of the impeller can be produced with full blades, smooth outer surface and good flow line, which can meet the requirements of the precision forging of impellers.

Effect of semi-solid forging temperature on microstructure and mechanical properties of Ti14 alloy

The influence of the semi-solid forging temperature between 1000 and 1100 °C on the microstructure and mechanical properties of a new α+Ti 2Cu alloy was investigated. The results indicated that more Ti 2Cu tended to precipitate on grain boundaries at a higher forging temperature, and finally formed a network structure after forging at 1100 °C. The precipitation was found to be controlled by both peritectic and eutectoid reactions. The elevated temperatures resulted in more liquid along the prior grain boundaries, which increased the peritectic precipitation in this region and formation of precipitation zones during re-solidification. In addition, the liquid served to relax the stress concentrations caused by dislocation pile-ups within the grains and provided more nucleation sites for eutectoid Ti 2Cu precipitates on grain boundaries. Hardness and room temperature tensile properties decreased as the forging temperature increased, and intergranular fractures were observed after semi-solid forging at 1050 and 1100 °C, which is also attributed to the grain boundary network obtained by semi-solid forging.

Forgeability and Flow Stress of Mg-Zn-Y Alloys with Long Period Stacking Ordered Structure at Elevated Temperatures

To develop a forging process for high strength Mg-Zn-Y alloys with a long period stacking ordered (LPSO) structure, the forgeability and flow stress of Mg97Zn1Y2 (at%) alloys were investigated with the upsettability test at an initial strain rate of 0.55 s � 1 . As-cast and extruded Mg97Zn1Y2 alloys can be successfully forged without fracture up to 0.5 and 1.0 respectively of average equivalent strain at a forging temperature of 773 K. To remove the influence of the temperature change during upsetting from the experimentally obtained flow stress curve, the isothermal flow stress curve was estimated by combining experimental results with finite element analysis. Furthermore, the mechanical properties of the forged Mg-Zn-Y alloys were measured, and the influence of microstructure on the forging properties was discussed.

Optimization of β/near-β forging process parameters of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si by using processing maps

The isothermal and constant strain rate compression tests of titanium alloy Ti-6.5Al-3.5Mo-1.5Zr-0.3Si are conducted by Thermecmaster-Z simulator and the deformation behaviors at the temperature of 990 ∼ 1080 °C and strain rate of 0.001 ∼ 70 s − 1 are extensively investigated. The processing maps (P-maps) under these deformation conditions are constructed and the forging process parameters are then optimized based on the generated P-maps. The experimental results show that most of the deformation is located at the flow instability zone when the strain rate is high ( ε̇ ≥ 0.6 s − 1 ). At the near-β forging temperature range, the feasible deformation conditions are (990 ∼ 1008 °C, 0.001 ∼ 0.01 s − 1 ) and its deformation mechanism is superplasticity. The optimum process parameters are (990 °C, 0.001 s − 1 ). At the β forging temperature range, when the deformation strain is smaller ( ε̄ ≤ 0.7), the suitable deformation conditions are (1035 ∼ 1070 °C, 0.001 ∼ 0.08 s − 1 ). The optimum deformation parameters, however, are 1055 °C and 0.001 s − 1 . If the strain is increased ( ε̄ = 0.8 ∼ 1.2), there are two feasible deformation zones, viz., (1008 ∼ 1025 °C, 0.001 ∼ 0.02 s − 1 ) and (1025 ∼ 1050 °C, 0.008 ∼ 0.16 s − 1 ), respectively. At the β forging temperature range, the main deformation mechanism is dynamic recrystallization.

Effect of copper addition on mechanical properties of 4Cr16Mo

Experiments conducted to determine the effect of copper addition on the machinabil-ity of plastic mold steel, 4Cr16Mo, were presented. The machinability of mold steel 4Cr16Mo was visibly improved by adding Cu. The top wear of 4Cr16Mo with copper was less than that without copper. The Cu-rich phase had the effect of a lubricant and the heat conductivity, which reduced cutting-tool wear, improved machinability. and increased the service life of the cutting-tool. Increasing of copper addition decreased the hot-working character of 4Cr16Mo. The optimal hot-working parameters for 4Cr16Mo with copper were determined by the tensile test and the compression test. The rate of deformation should be adopted as 0.6 s- 1 . The heating-up temperature, initial forging temperature, and terminal forging temperature were 1200° C, 1150° C. and 950° C, respectively.

Drop forging of HSLA steel with application of thermomechanical treatment

Problems of realization of thermomechanical treatment for microalloyed-steel forgings are presented. The issue is discussed on the example of high-pressure-pump crankshaft. On the strength of numerical analysis results conditions for favourable strain and temperature distribution were determined. In addition, by means of numerical modelling proper perform geometry was designed, which allowed elimination of costly trials in industrial conditions, necessary especially for this part due to inclination to fold formation. The knowledge of precipitation kinetics in the analysed steel in combination with the obtained profiles of temperature made it possible to determine appropriate forging temperature, time, rate and a scheme of cooling. The experimental tests run in industrial conditions confirmed reasonability of assumed technology. Mechanical testing proved required high ultimate strength and yield stress and ductility.

Plastic forming of the equal-channel angular pressing processed 6061 aluminum alloy

Plastic formability of the ECAP processed 6061 Al alloys with ultrafine grains was examined at relatively low forming temperatures in range between 443 and 553 K. The ECAPed 6061 Al alloys after 8 and 12 passes with submicron size grains and high fractions of high angle boundaries exhibited excellent forging and micro-extrusion abilities. High quality surface was another advantageous feature of the ECAP processed samples. Compressive forging on the 8 passes 6061 Al at 523 K, however, resulted in sharp decrease in strength due to dynamic recovery accelerated in the ultra-fined (sub)grained structure. Micro-extrusion on the 12 passes 6061 Al with 2 mm in diameter was successful at 443 and 553 K. Extrusion without losing the high strength gained through using ECAP, however, could be realized only at 443 K, indicating that high strength components could be made out of the ECAPed 6061 Al using plastic working when the processing temperature was chosen to be much lower than the conventional forging temperature of ∼753 K.

Superplastic Sinter-Forging of Fine-Grained Si<sub>3</sub>N<sub>4</sub>-Si<sub>2</sub>N<sub>2</sub>O Composite at Low Temperature

The Si3N4- Si2N2O composites are fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering (LPS) method. XRD analysis shows sintered body consists of β-Si3N4 and Si2N2O. SEM experiment conforms that the average grain size of sintered body is less than 300nm. The complex-shape gears can be formed by a sinter-forging technology when the sintering temperature is 1600°C and the superplastic forging temperature is only 1550°C. Rod-shaped grains aligned along the perpendicular direction of pressure and the mechanical properties increase about 10% after the materials were forged.

Effect of Cu and Mg on Forging Property and Mechanical Behavior of Powder Forged Al-Si-Fe Based Alloy

Two atomized alloy powders, those chemical compositions are Al-10Si-5Fe-1Zr and Al- 10Si-5Fe-4Cu-2Mg-1Zr, were pre-compacted by cold pressing with 350MPa and subsequently hot forged at temperatures ranging from 653K to 845K and at an initial strain rate of 10-2/s in order to produce bulk cylindrical type alloys with the diameter of 10 mm. The addition of Cu and Mg into the present alloy causes a decrease in the eutectic reaction temperature of Al-10Si-5Fe-1Zr alloy from 841K to 786K and results in a decrease of flow stress at the given forging temperature. TEM observation revealed that in addition to Al-Fe based intermetallics, Al2Cu and Al2CuMg intermetallics appeared to display the alloying effect additionally. The volume fraction of intermetallic dispersiods increased by the addition of Cu and Mg. Compressive strength of the present alloys was closely related to the volume fraction of intermetallic dispersoids.

Formation of Submicrocrystalline Structure in Titanium Aluminides and their Mechanical Properties

An approach for producing bulk products of intermetallic Ti-25Al, Ti-46Al and Ti-22.9Al-22.7Nb-2.4(Zr,V,Si,C) alloys with a submicrocrystalline structure is proposed. The approach is based on multi-step a-b-c hot forging with a reducing forging temperature. During forging dynamic recrystallization occurred resulting in continuous grain refinement as the working temperature decreased. Grain sizes from 0.1 to 0.5 μm were produced in the titanium aluminide alloys. The production of a nanocrystalline structure of size d<0.1 μm using this method seemed to be unfeasible since drastic embrittlement of the alloys took place which may be ascribed to partial disordering of the titanium aluminide alloys. The intermetallic materials with submicrocrystalline structures exhibited superplastic properties in a wide temperature range (600-1000°C). In the fully ordered Ti-25Al alloy room temperature ductility increased with decreased grain size, while ductility of partially disordered Ti-25A1 and ordered Ti-46Al alloys was close to zero at room temperature. The increased ductility was found to be correlated with an enhanced grain boundary relaxation capability at increased temperature and decreased grain size.