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Based on the advantages of laser shock forming, such as high-speed dynamic loading, good filling ability of die cavity, and improving material formability along with its other advantages of warm forming to improve forming discreteness and further develop formability, a warm laser shock micro-heading forming (WLSMHF) method was investigated, and an experimental system was established. Combining ALE method in ABAQUS with experiment, the feasibility was studied with T2 copper. The propagation of stress wave, deformation process, and material flow law was studied. The influence of laser energy, temperature, and grain size on the deformation of upsetting head was studied. The influence of forming temperature and grain size on forming discreteness was analyzed. Results show that the phenomenon of the anti-Taylor anvil impact test first appears in the whole rod. When the inside of the die is filled with material, the deformation of the material outside the die is similar to that of micro-upsetting. The upper end of the upsetting head is slightly larger than the lower end because of the propagation of stress wave, inertia effect, and the restraint of the die to the material. The flow speed of the metal material in the die is fast, the die is filled well, and the filling property of the die is good. The deformation of upsetting head increases with the laser energy and temperature, which improves the formability of the material. The deformation of the upsetting head increases with the grain size, and the effect of grain size on forming can be reduced by increasing the forming temperature simultaneously. The increase in the forming temperature and decrease in the grain size can improve the discreteness of the forming size and forming accuracy, respectively.

The effect of electron plasma removal of scale, flaws, and various contaminants from the surface of rolled steel bars on the structure, properties and surface quality of the rolled articles for cold heading is studied.

Laser-assisted machining (LAM) is a type of hybrid material removal process, which is used for locally and instantaneously decreasing the hardness of materials, such as ceramics and hard composites, by irradiating the material with a focused laser during mechanical cutting. LAM, which has been studied primarily for the macro-machining of the hard materials, was applied to the micro-turning process of high hardness steel for a micro-lens mold in this research. The laser-assisted micro-turning (LAμT) process was analyzed using finite element modeling to predict the thermal effects and temperature distributions induced by irradiation of a focused laser and to determine critical cutting parameters, such as spot size, heading distance, and feeds. The effects of the LAμT were verified by an in-situ comparison with conventional micro-turning method, and the cutting conditions were optimized to maximize the cutting performances in terms of cutting force, surface finish, and chip exhaust. Consequently, a lower cutting force and better surface finish was demonstrated compared to the conventional method for the optimized LAμT condition. Therefore, this study showed that the LAμT can be successfully applied to the micro-machining of hard molds.

In pursuit of developing environmentally friendly techniques for machining, a lot of hard work has been done by researchers all over the world, and many fruitful results have been obtained. When focussing on cooling techniques, minimum quantity lubrication (MQL) is one such development that has proven to be highly useful in leading to a greener manufacturing process. The need of the hour is not just to compare its (MQL) benefits to dry and flood cooling. Rather, certain improvements need to be introduced in the MQL process to make it more effective and improve its performance. In this study, a similar effort has been made by introducing a Ranque-Hilsch vortex tube into the MQL process. Turning of commercially pure titanium (Grade 2) was commenced using uncoated tungsten carbide inserts. Variations in speed, feed and depth of cut were made. The experiments were designed using response surface methodology, and analysis of variance (ANOVA) was performed to identify the effect of the input parameters on the responses, i.e., surface roughness, cutting force, power and flank wear. Optimizations of the results proved that the Ranque-Hilsch vortex tube made significant improvements in the results and was suggested as a better method. These predictions were experimentally validated, thus making the MQL process more effective with a negligible cost addition and heading to a greener future in manufacturing industry.

Fatigue failure is defined as the progressive degradation of the strength of a structural component during the manufacturing of machine tools. As the increasing demands for high product quality result in a continuing need to achieve improvements in fatigue reliability on machining tools, many researches have been focused on it in recent decades with a result of many valuable contributions. However, current researches always focus on the fatigue analysis of rigid components, and the dimension change, necessary design, and optimization are lacked, while the component of a product is always a rigid-flexible coupling multi-body system, which could affect the accuracy and reliability of fatigue analysis, and parameterization help designers see each dimension change. This paper proposed a process of component fatigue analysis based on rigid-flexible coupling virtual prototyping. In this paper, a crankshaft in the cold heading machine is taken as an example to show the rigid-flexible coupling fatigue analysis process in detail. After the parameterization of the crankshaft is proposed, the static analysis and optimization of the crankshaft is carried out. The dynamics analysis for rigid-flexible coupling of the cold heading components is also proposed. The fatigue analysis for the crankshaft is discussed in detail. The crankshaft in the cold heading machine is given as an example, which demonstrates that the methodology is obviously helpful to fatigue analysis and simulation. The physical prototyping is also carried out to demonstrate the fatigue reliability. The crankshaft of cold heading machine is given as an example, which demonstrates that the methodology is obviously helpful to fatigue analysis and simulation.

Carbon emission has become a recent global concern for green manufacturing. Production is one of the main sources of carbon emission. As the design of a product determines over 70 % of its life cycle costs, with extensive impacts on the environment, it is important to decrease the product carbon footprint in the product design stage. As the activity data is directly related to the mass of the product, the lightweight of product is a valid approach to low-carbon footprint. However, the existing lightweight design method primarily takes structure or material into consideration without the consideration of environmental factors. The product lightweight design under the low-carbon footprint constraint is proposed in this paper, which serves low-carbon footprint as an important benchmarking for product performance. This paper then presents a general lightweight design for product low-carbon footprint through structural optimization. The design of a cold heading machine is used to demonstrate the proposed methodology.

To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating conditions. Experimental results show that the bubble region in the jet device has a constant vapor pressure, which creates a good condition for liquid absorption, while it shrinks with increasing outlet pressure. The liquid absorption amount keeps unchanged when the outlet pressure is lower than a critical value. The critical outlet pressure increases by 40% with decreasing cavitation absorption amount, which is especially suitable for mini-flow quantitative addition of foaming agent used for foam dust suppression. Its effectiveness on suppressing mine dust was evaluated in a heading face of underground coal mines. Field application indicates that the reliable and simple foaming system adopting the new adding method makes a marked dust suppression effect. The working environment of heading face is significantly improved, ensuring the safe tunneling and personal security.

Cold forming generally allows the fast generation of parts with very low tolerances. In addition, mechanical properties are improved, if work hardening materials are used. Transferring the cold forming process to micro range leads to a decrease in the maximum achievable upset ratio so that the forming process becomes inefficient. Therefore, a laser-based free form heading process has been developed to generate preforms which can be calibrated in a secondary cold forming step. The achievable upset ratios reach values of several hundreds instead of 2.1 which is common for single step mechanical upsetting. In this article, heat losses arising in the material accumulation process using laser-based free form heading are analyzed and discussed. For this purpose, the process is modeled within the framework of continuum mechanics and simulated by a finite element method. By using a numerical approach, a systematic study on heat losses is performed in order to identify the influence of radiation, heat transfer due to convection and thermal conduction during laser irradiation time. The simulation results, which are validated with experimental data, show that the radiation is the most important mechanism reducing the efficiency of the accumulation process.

The design of upset forged metal parts by cold heading is presently well established. Major operating parameters are identified and the typical modes of deformation that may occur during the process are fully characterized. In contrast to metals, there is no research work and no practical design rules in the specialized literature concerning the cold heading of polymer parts. This paper is concerned with the abovementioned lack of knowledge and is a contribution toward the application of cold heading to polymers. The experimental research work makes use of polyvinyl chloride (PVC) and the overall findings are interpreted in the light of an innovative extension of the flow formulation that is capable of modeling cold forming of pressure-sensitive materials under a nonassociated flow rule. Emphasis is placed on the deformation mechanics of cold heading applied to PVC and on the influence of the major operating parameters on the overall formability limits of the process. Results show that cold heading of PVC can be successfully utilized for producing upset forged parts.

A model is proposed for simulating the cold deformation process of titanium alloys. The emphasis is on the description of the physical metallurgical processes and not the detailed mathematical formulation and calculations. The model will be a useful step toward understanding cold heading, an important metal processing technology.

Thermomechanical controlled processing (TMCP) of low carbon cold heading steel in different austenite conditions were conducted by a laboratory hot rolling mill. Effect of various processing parameters on the mechanical properties of the steel was investigated. The results showed that the mechanical properties of the low carbon cold heading steel could be significantly improved by TMCP without heat treatment. The improvement of mechanical properties can be attributed mainly to the ferrite grain refinement due to low temperature rolling. In the experiments the better ultimate tensile strength and ductility are obtained by lowering finishing cooling temperature within the temperature range from 650 °C to 550 °C since the interlamellar space in pearlite colonies become smaller. Good mechanical properties can be obtained in a proper austenite condition and thermomechanical processing parameter. The ferrite morphology has a more pronounced effect on the mechanical behavior than refinement of the microstructure. It is possible to realize the replacement of medium-carbon by low-carbon for 490 MPa grade cold heading steel with TMCP.

We applied a combined two- and three-dimensional (2D and 3D, respectively) simulation techniques to analyze a sequence of multistage automatic cold-forging processes. After discussing recent forging simulation technology, a rigid-plastic finite element-based forging simulator known as AFDEX was introduced. A five-stage cold-forging sequence was selected as a representative example of multistage automatic forging processes because it has four axisymmetric forging stages followed by a non-axisymmetric forging stage and involves piercing and heading processes accompanying folding and overlapping. The importance of using a combined 2D and 3D simulation was illustrated in terms of the solution precision and accuracy, and computational efficiency.

A criterion for predicting the workability limits for internal britde failure was developed for cold heading of 1038 steel. The criterion considers internal defects caused by microstructural changes generated by adiabatic shear. This transformation is termed the transformed adiabatic shear band (TASB) phenomena. The defect that develops is the formation ofbritde martensite as a result ofthe temperature rise and fall inside the adiabatic shear band (ASB). In this work, the material is considered to have a TASB defect when the temperature inside the ASB exceeds the phase transformation temperature (AC3). The empirical formulas provided by Andrews[1] were used to determine transformation temperatures. Microhardness testing and etching with 2% Nital and Le Pera etchants were performed on the sectioned specimens to locate and study the TASB. In order to simulate the cold heading process, a drop weight compression test was used and modeled with finite-element analysis (implemented within ABAQUS/Explicit).

Theoretical and experimental studies have been made to find the efficient surface shape of the working member of the electrothermomechanical rotary machine and the position of the infrared radiators (IRRs) and the mechanical tools that take into account the interactions of the electrothermal (ET) and mechanical parameters. The authors studied the face shapes for different ET systems: a single flat IRR, a group of fixed IRRs, or a group of IRRs rotating around a common axis.

This paper describes how a model material technique has been applied in the analysis and development of a roll forming process for heading shanks, gun nails in particular. A commercial modelling wax “Filia” is extruded to the dimension of the model shank before the head is roll-formed by means of equipment designed for this process. The dependence of the roll diameter, of the velocity between the roll and the tool, and of the interface friction are shown for the model technique and compared with a theoretical estimate and with experimental results. A compound wax is used to study the proportion of virgin surface from the cropping in contact with the roll and the tool. A machine for production of gun nails was developed based on the model analysis. Experiments carried out with this machine confirm the results and the advantage of the model material technique.

Previous experimental work has focused on determination of forming limits in terms of local strains. The present study extends this approach. Fracture loci and strain paths were determined experimentally from cold upset tests on cylindrical specimens. Several combinations of cylinder length, diameter, lubrication conditions, and die surfaces were used to determine the influence of these parameters on fracture. Strain paths have been shown to be process and geometry dependent but material independent. On the other hand, fracture loci depend upon material properties but not on process parameters. The point of intersection of the process strain path with the material fracture locus represents fracture. Using a series of curve-fitting techniques, expressions were developed for determining this point in terms of process and material parameters.

Forging processes in the past have primarily been developed based on empirical relationships or trial and error. The finite element approach to forging process development and design has been found to be practically feasible and economical. The rigid-viscoplastic finite element method (FEM) code “ALPID” developed by Battelle Columbus Laboratories, has been successfully utilized to simulate metal forming processes. In the following paper, the application of finite element simulation to study deformation mechanics in the forging of gear blanks and axle shafts is discussed. An underfill problem on the gear blank was overcome and tool life was improved on the axle shaft hot heading process.

Heat treatment that includes brief tempering with rapid cooling ensures a noticeable refinement of the structure and helps substantially to increase the life of tools operating at normal temperatures.

The Krivoi Rog Metallurgical Plant is one of the main suppliers of starting strip made of lowand medium-carbon steels. After sizing, this strip is used mainly to make fasteners by the method of cold heading. The steel for the strip is made in converter shops. Ingots weighing 8 and 12 tons are rolled on three billet mills into billets 80 • 80 and 150• 150 mm in cross section. After their surfaces are conditioned, the billets are rolled on lightsection mills into bundles weighing 540 kg and 1.7-2.0 tons or into bars 12-30mmindiameter.

1. The criteria used in selecting materials for tools must be chosen in accordance with the operating conditions of the tool. 2. Heading dies with an adequate service life can be obtained only by preliminary compression of the material near the working surface, for which purpose composite dies are the best. 3. The criterion for selecting the material to ensure the strength of inserts in composite dies should be the resistance to compression and not the toughness, tensile strength, fatigue strength, or any other mechanical property.

1. When cold-heading dies of carbon tool steel are quenched the depth of the hardened layer increases from 2.2 to 2.7 mm with an increase of the water pressure from 1 to 8 atm, and the hardness of the surface layer increases from HV 650 to HV 725. 2. The durability of the die increases with the hardness and the depth of the hardened layer. 3. Dies with a working diameter up to 6 mm should be quenched at water pressures of 4–5 atm, and with a working diameter over 6 mm at water pressures of 6–8 atm.