Forging Temperature Research Articles

Research on improving the automatic stability of trimming unit

Abstract Due to the influence of temperature and other factors in the forming of forgings, the shape of the forging fringe is often challenging to control and predict, which restricts the operation of forging automation. In this paper, the forging position is detected by the vision means, which is conductive to identify whether the production process is normal or not to avoid the loss caused by the interruption of the production unit. Meanwhile, for the forging temperature changes on visual recognition, the relationship curve between forging temperature and exposure time is determined by statistical method, so that the temperature of the forging regulate the visual camera exposure time to improve the accuracy of visual recognition.

Microstructure and property evolution of CuCr50 alloy prepared by aluminum thermal reduction-electromagnetic casting during hot forging process

To address the problems of low performance and density in CuCr50 alloys prepared by aluminum thermal reduction-electromagnetic casting, a synergistic process involving hot forging deformation to eliminate micropores in the alloy and heat treatment to modify the alloy was proposed. The effect of hot forging temperature on the microstructure evolution and performance strengthening of CuCr50 alloys during heat treatment was studied. The results show that the properties of CuCr50 alloys forged at different temperatures after heat treatment are better than those after direct heat treatment. After heat treatment, the conductivity of CuCr50 alloys forged at 800 °C reaches 22.41 MS/m, the density reaches 7.94 g/cm3, and the hardness reaches 112 HB, which are 73.59 %, 4.75 % and 37.59 % greater than those of the as-cast alloy, respectively. The microstructure analysis showed that the nano-Cr phase precipitated during the aging process of CuCr50 alloys after hot forging at 750 °C–850 °C had a semi-coherent relationship with the Cu matrix, which played a role in coherent strengthening. After hot forging at 900 °C, the precipitated Cr phase has an incoherent relationship with the Cu matrix, which played a role of dispersion strengthening. The performance test of 40.5 kV simulated vacuum interrupter shows that the breaking and chopping performance of the prepared CuCr50 contact material is obviously better than that of commercial products, which is expected to become a new process for the preparation of high performance CuCr contact materials.

Prediction of Microstructure Evolution in Ball Mill Liner Forging Process

The liner is affixed to the inner side of the ball mill cylinder to protect the cylinder. Through isothermal compression experiments, Arrhenius constitutive models, peak strain models, critical strain models, dynamic recrystallization dynamic models, and grain size models suitable for the forging process of Mn–Cr–Ni–Mo steel used in ball mill liners were established. By utilizing Deform software, a 3D thermo‐force‐structure coupling model for the hot forging process of ball mill liners was constructed, and the volume fraction of dynamic recrystallization and average grain size during forging was predicted. The response surface model was employed to investigate how process parameters interacted with each other and affected microstructure uniformity in ball mill liners. After optimization, the optimal parameters were determined: initial forging temperature at 1200 °C, forging speed at 30 mm s−1, and friction coefficient at 0.3. Subsequently, a hot forging experiment on ball mill liners was conducted using these optimized parameters; samples were analyzed through backscattered electron diffraction device experiments and microscopic tissue observations. Results demonstrated that microstructural changes observed during actual forging processes aligned with numerical simulation results—thus verifying both the accuracy of the Mn–Cr–Ni–Mo steel material model and numerical simulation method.

The impact of induction heating time on the temperature distribution of high-temperature alloy discs

Abstract The induction heating time is directly related to the temperature uniformity of high-temperature alloy disc components. Therefore, investigating the influence of induction heating time on the temperature field distribution of disc components provides guidance for temperature control strategies in the forming process. In this study, the finite element analysis software COMSOL Multiphysics was employed to examine the impact of induction heating time on the radial and thickness-wise temperature fields of GH4169 discs. The results indicate that the heating time affects the thickness of the heating layer, and appropriately extending the heating time can improve the temperature uniformity in the thickness direction, achieving a temperature difference of ±5 °C in the disc component thickness direction under certain conditions. When the heating time ranges from 1229 s to 1239 s, the temperature in the R=30 mm to R=100 mm range reaches the suitable forging temperature.

Hot deformation behavior and processing workability of a powder forged Fe-2.1Cu-0.5C alloy

Hot deformation behavior of as-sintered Fe-2.1Cu-0.5C alloy was evaluated through the construction of constitutive equations and a hot processing map. The hot deformation behavior was investigated at different temperatures and strain rates and microstructure observations were subsequently conducted. Flow stress for the initiation of dynamic recrystallization mechanism was determined. Tensile and fatigue strength tests were conducted at room temperature. It was observed that the microstructure of the alloy forged at lower temperature exhibited smaller grain size and its grain size increased with higher forging temperatures. Mechanical testing results revealed that an increase in the forging temperature led to a lower tensile strength and a higher fatigue strength. This change can be attributed to the larger grain sizes and the reduction of microcracks. A forging temperature at 1050 °C was recommended to achieve optimal mechanical properties for powder forged Fe-2.1Cu-0.5C products. These results might give some hints for optimizing process conditions and improving mechanical properties of powder metallurgy alloys by the use of constitutive equations and thermal processing maps.

Effect of hot forging temperature and diamond volume fraction on TiC interface evolution and thermal conductivity of hot-forged Ti-coated diamond/Cu composites

Diamond/Cu composites are developed as a solution to the challenge of dissipating heat in electronic devices, due to the potential to have a high thermal conductivity (TC) and a coefficient of thermal expansion (CTE) close to that of the electronic devices. In this study, Ti-coated diamond/Cu composites were fabricated by hot forging. Fabrication parameters were manipulated by altering the volume fraction of diamond and adjusting the hot forging temperature to determine the optimal combination of parameters to produce Ti-coated diamond/Cu composites with high TC. The microstructure of the hot-forged composites and the interface characteristics were characterized by SEM, and the interfacial bond strength between the copper and the diamond was assessed based on tensile test results. Compared to other fabrication temperatures of 700 °C and 850 °C, 800 °C is the optimal hot forging temperature to facilitate the dynamic formation of TiC interface layer and ensure a high interface coverage rate on the diamond particles. Additionally, the volume fraction of diamond affects the interface microstructure and TC of the hot-forged composites by affecting the heating behaviour of the composites during induction heating. As a result, 800 °C hot-forged composites with a composition of 45vol%Ti-coated diamond achieved the highest TC (455 W/mK) among the fabricated composites and exhibited good ductility at a high tensile strength of 124 MPa. The findings indicate that the high TC of the Ti-coated diamond/Cu composites are ensured by the synergy of uniform distribution of diamond in the matrix, a rough interface, and strong interfacial bonding between the copper and the diamond. This paper provides insights into the TiC interface formation mechanisms occurring during the induction heating and hot forging fabrication process.

Influence of temperature and cumulative strain on microstructure and mechanical properties of multi-directional forged Mg-Gd-Y-Zn-Zr alloy

The multidirectional forging (MDF) experiments of Mg-Gd-Y-Zn-Zr alloy were performed. The effects of temperature and cumulative strain on microstructure and mechanical properties of multi-directional forged Mg-Gd-Y-Zn-Zr alloy were studied. The results showed that the recrystallization ratio of the alloy gradually increased with the initial forging temperature after 3 passes of MDF. Under the condition of the initial forging temperature of 500 °C, the grain size was gradually refined with increasing MDF passes, and the average grain size was refined to 1.49 μm after 12 MDF passes. With the increase in MDF passes, the maximum texture density of the alloy gradually decreased. The mechanical properties gradually increased with the MDF passes. In the first 6 MDF passes, the mechanical properties greatly increased, but after that, the increase gradually slowed down with additional MDF passes. The optimal mechanical properties were obtained after 12 MDF passes, and the tensile strength, yield strength, and elongation after fracture were 362 MPa, 294 MPa, and 14.5%, respectively.

Optimization of hot deformation parameters for multi-directional forging of Ti65 alloy based on the integration of processing maps and finite element method

In this paper, the hot deformation behavior of Ti65 alloy was investigated over the temperature range of 930–1110 °C with the strain rate of 0.001–1 s−1. According to the stress-strain curves, the constitutive equation was developed to describe the flow behavior of Ti65 alloy. The processing maps were constructed based on the dynastic materials model (DMM) and the perfect formability zone of Ti65 alloy is found under the temperature of 970–1020 °C and the strain rate of 0.001–0.1 s−1. In addition, a three-dimensional nonlinear transient thermo-mechanically coupled finite element model of the multi-dimensional forging (MDF) process of Ti65 alloy was developed. The effects of the forging temperature and forging speed, on the temperature rise, residual stress, and grain refinement were predicted. By analyzing the temperature and stress distribution, the optimum forging temperature and speed for Ti65 alloys were determined to be 1000 °C and 10 mm/s, respectively. Increasing the forging temperature or reducing the forging speed reduces the temperature rise and the maximum tensile stress, thus reducing the risk of cracking. Additionally, the equivalent strain increases as forging speed decreases. Simultaneously, the accumulated strain is more significant for the inside of the forgings. The results of this research are instructive for the optimization of the MDF process.

Life cycle assessment of direct recycling hot press forging of aluminium AA7075 metal matrix composite

The primary objective of this research is to investigate the process of direct recycling of AA7075 aluminium alloy, which is extensively utilised in the aerospace and flight sectors due to its exceptional strength and lightweight characteristics. Alumina (Al2O3) is used as a reinforcing agent and the effect of hot press forging (HPF) parameters on the mechanical characteristics and surface integrity of the metal matrix composite (MMC) constructed of AA7075 alloy with 1% Al2O3 has been studied. Furthermore, the utilisation of an integrated life cycle assessment (LCA) approach is implemented to assess the environmental impacts and economic expenses associated with the recycling of aluminium via high-pressure forming for both the metal matrix composite and AA7075 alloy. Response surface methodology (RSM) is applied to ascertain the optimal parameters for high-performance filtration. The findings suggest that employing a forging temperature of 532.34 °C and a holding time of 60 min produces favourable results. When comparing the characteristics of the MMC and recycled aluminium, it can be observed that they both demonstrate similar essential process attributes. The utilisation of HPF in conjunction with the Multi-Material Composite has the potential to yield a reduction of up to 24.97% in Global Warming Potential (GWP). This research demonstrates the efficacy of HPF as a viable approach for environmentally conscious and economically efficient recycling of AA7075 aluminium scrap, thereby improving product performance and promoting sustainability.

Upset Forging Temperature Effect on Structure and Tribological Properties of Sintered Al–7Fe–38Sn Alloy

Upset Forging Temperature Effect on Structure and Tribological Properties of Sintered Al–7Fe–38Sn Alloy

Enhancing hot ductility of a cryogenic high manganese steel at a high strain rate by matrix homogenization

The high temperature brittle zone of cryogenic high manganese (Mn) steel often leads to transverse cracks during hot working process, which seriously hinders the production of its sheets or wires. In the present work, we found that the brittle zone (at temperatures between 800 and 900 °C) can be effectively enhanced by homogenizing the initial microstructure and composition. It was revealed that the elements such as Mn and C tend to be enriched in the inter-dendrite area of the as-cast samples, which is difficult to eliminate even during high temperature forging. The C segregation promotes the formation of fine precipitates, such as NbC and Cr23C6. These carbides are usually located at or near grain boundaries, which can weaken grain boundary cohesion and deteriorate the hot ductility. However, homogenizing the initial composition helps to increase the size of hybrid precipitates containing TiN, WC, MoO2 and WO3 and inhibit the precipitation at grain boundaries. Meanwhile, homogenizing the initial microstructure size and stored energy reduces the critical dynamic recrystallization (DRX) temperature to 850 °C. A lower Z value and critical DRX stress increase the DRX fraction from 24% to 66%, which recover microstructure and inhibit grain boundary slip.

In situ analysis of phase constituents evolution upon hydrogen cycling of cold-forged Mg-Ni powders

Development of hydrogen storage in metal hydrides requests efficient, simple and safe processes such as room temperature forging. Samples elaborated in this way from Mg and Ni powders result in bulk pellets whose only identified phases are Mg and Ni. Deuterium absorption occurs from 250 °C in these samples due to the co-existence of basal fiber texture and structural defects, both induced by forging. In situ neutrons diffraction analysis shows the progressive formation of the Mg2NiD0.3 / Mg2NiD4 phases upon deuterium cycling and allows to identify the multi-step absorption and desorption mechanisms at temperatures as low as 270 °C. The growth of the Mg2NiD0.3 / Mg2NiD4 phases occurs in a short time during the second step of the deuterium absorption – as Mg2NiD0.3 transformed into Mg2NiD4 – and progresses from the periphery of the initial Ni particles towards their center. The mechanism is controlled simultaneously by deuterium diffusion and migration of Mg atoms through the already formed Mg2NiD4 deuteride. The reaction between Mg and Ni is not observed in the absence of deuterium, even after annealing at 285 °C for 48 h, thus we evidence a deuterium-induced mobility of the metal atoms.

Forging Temperature Effects on Crack Tip Creep Behaviour of Hot Hammer Forged Ti-6Al-4V Alloy

The creep behaviour of hot hammer forged Ti-6Al-4V alloy under different forging temperatures has an essential influence on their high-temperature service performance. In this article, the high-temperature mechanical property and creep behaviour of Ti-6Al-4V alloy forging at different forging temperatures were first investigated experimentally. Then, in view of the critical effect of microcracks and other defects on the service life of components in forging, the creep characteristics at the tip of a 2 mm crack were characterized by the finite element method. The results show that when the Ti-6Al-4V alloy was forged at 1000°C, the high-temperature mechanical property was improved, and the steady-state creep rate and creep residual deformation were significantly reduced. In addition, the creep strain and creep rate at the crack tip were decreased apparently during creep, and the creep strain gradient in the crack tip region was also significantly reduced. This indicates that the creep deformation of Ti-6Al-4V alloy can be controlled by an appropriate forging temperature during hot hammer forging process and might delay the crack propagation to improve the service life of components.

Effect of α+β solution treatment and aging on the performance of powder forged Ti-5Al-2.5Fe

ABSTRACTAmongst titanium alloys, the α+β Ti alloys are the ones with the best compromise between strength and fracture toughness. However, the applicability of α+β Ti alloys is limited by their higher cost compared to other structural metals. Reduction of the cost can be obtained using cheaper alloying elements and creative manufacturing processes. This study aims to investigate if α+β Ti alloys can be produced at lower cost using powder forging and to understand the effect that the post-forging α+β solution treatment and aging have on the microstructure and mechanical properties. We demonstrate that the proposed approach is a viable alternative to manufacture α+β Ti alloys and that the chosen forging temperature (i.e. thermal history) is critical for producing high-strength ductile alloys. The microstructural modification induced by the α+β solution treatment and aging generally increases both the strength and the ductility, but the actual improvement is still dictated by the conditions used to thermomechanically deform the α+β Ti alloy.

High-Temperature Wear Properties of 35Ni15Cr Fe-Based Self-Lubricating Die Materials

Hot forging dies play an important role in metallurgy, automotive, aerospace and weapons industries. However, due to the high temperature and high pressure of hot forging die and the working environment of cyclic load, the friction and wear performance of hot forging die is poor and the service life is low. The use of traditional lubricants can prolong the life of the mold, but it will cause environmental pollution, harm to workers’ health and other problems. In this paper, 35Ni15Cr Fe-based self-lubricating die material was prepared by high energy ball milling and vacuum sintering. The wear properties of the materials were studied under ball-to-disc wear conditions at 600 °C. The results show that when CaF2 content is 8 wt%, the friction coefficient and wear rate of the material are the lowest, which are 0.3 and 0.9166 × 10−5 mm2 min−1, respectively. When the load increases, the friction coefficient first increases and then decreases, but the wear rate continues to increase. The wear mechanism mainly includes abrasive wear, adhesive wear, oxidation wear and fatigue wear. The friction reduction mechanism is that CaF2 is precipitated from the self-lubricating mold material and Fe and Ni are oxidized to the boss on the wear surface. The broken boss and lubricant form a lubricating film and accumulate into a glaze layer. The material can be used in high temperature forging environment without additional lubricant.

Thermal deformation behavior and processing maps of nickel-free high nitrogen austenitic Cr18Mn16Mo2.5N0.83Nb0.15 stainless steel

The nickel-free high nitrogen austenitic Cr18Mn16Mo2.5N0.83Nb0.15 stainless steel was fabricated by electroslag remelting technology. The high-temperature thermal deformation behavior of as-fabricated steel was investigated using Gleeble-1500D type thermal-mechanical simulation testing machine under the condition of the temperature range from 950 °C to 1100 °C and the strain-rate range from 0.01s−1 to 1.0s−1. The constitutive equation containing polynomial of as-fabricated steel was built to describe stress function containing the variable of deformation temperature and strain-rate based on Arrhenius equation. The Q value is 448.915 kJ mol−1 by computing using the experimental data obtained from the thermal deformation tests. The thermal forging temperature should be higher than 1050 °C and the strain-rate below 1s−1 based on the thermal processing maps.

Multi-directional forging of large-scale Mg-9Gd-3Y-2Zn-0.5Zr alloy guided by 3D processing maps and finite element analysis

The three-dimensional (3D) processing maps of cast Mg-9.0Gd-3.0Y-2.0Zn-0.5Zr alloy were established based on isothermal compression tests and dynamic material model (DMM). The stable and power-efficient forming domains were determined by considering both the instability and power dissipation efficiency maps. Multi-directional forging (MDF) was then simulated by employing finite element (FE) analysis in the Deform-3D software, using the 3D power dissipation efficiency maps as input. The optimal forging parameters were thus obtained for a large-scale ingot with 430 mm in diameter and 440 mm in height, i.e., a forging temperature of 450 °C and forging speed of 10 mm/s. Finally, a Mg-9.0Gd-3.0Y-2.0Zn-0.5Zr cake-shaped forged part with 900 mm in diameter and 100 mm in height was produced. After T6-heat treatment, the edge and center of the forged part exhibit homogeneous microstructure and relatively consistent properties, with the tensile strength, yield strength, and elongation being about 400 MPa, 320 MPa, and 14.0%, respectively. Using transmission electron microscopy, the main strengthening phases were revealed to be the dense nano-scale β′ phases that are uniformly distributed inside the material.

Corrosion Protection of ZK60 Wrought Magnesium Alloys by Micro-Arc Oxidation

The influences of the forging process and micro-arc oxidation (MAO) coating on the corrosion behavior of ZK60 wrought magnesium alloys exposed to salt spray and constant stress corrosion conditions were investigated. The microstructure of the ZK60 Mg alloy specimens forged under different temperatures (i.e., 250, 300, and 450 °C) was characterized using metallography, EBSD, and SEM. It was demonstrated that the ZK60 alloy forged at 300 °C (i.e., ZK60EF-300) had finer grain and uniformly distributed β-phase and, thus, better corrosion resistance than the ZK60 forged at 450 °C. At the lower forging temperature (250 °C) twins formed in the ZK60 alloy, which accelerated the corrosion of the ZK60E-250 specimen. The MAO coating provided robust corrosion protection for all the ZK60 wrought Mg alloy substrates. The salt spray corrosion test results showed that when the MAO coating broke down at certain weak sites, the corrosion performance of the coated Mg alloy was predominantly determined by the alloy substrate. The stress corrosion behaviors of the uncoated and MAO-coated ZK60 alloy specimens were also investigated under a constant load of 80 MPa in 3.5 wt.% NaCl solution. The MAO coating was found to improve the stress-corrosion resistance of the ZK60 alloy pronouncedly.

The ultra-high temperature forging process based on DEFORM-3D simulation

The ultra-high temperature forging process based on DEFORM-3D simulation

Study on multi stage forging process with combination of different strain rate and temperature region in IMI685 aero engine compressor disc forging

IMI 685, a near alpha Ti alloy has been used in high pressure compressor discs for aero engine application due to its high strength to weight ratio and high creep resistance. Manufacturing process plays an important role in obtaining the required mechanical properties for the highly complex and critical products. The suitable manufacturing process is not available in open literature. Hence, in this paper non-isothermal approach of manufacturing compressor disc combining hydraulic press and pneumatic hammer at different temperature for different stages of forging has been explored. Mechanical and metallurgical analysis of processing in partial α-β/β temperature range resulted in higher creep resistance with acicular/needle alpha platelets with a basket weave structure. This experiment has proven that with a proper selection of thermo mechanical processing parameters (combination of different forging temperature and strain rates in forging sequence), required creep properties can be met with the non-isothermal processing route.