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The incremental radial forging process employs several tens or hundreds of incremental local strokes, so that the entire process is difficult to analyze due to large computation time and large computer memory. The objective of this work is to propose a new numerical scheme of the finite element method, automatic expansion of domain (AED), to reduce computation time and computer memory. In the AED scheme, an effective analysis domain in each local forging step is defined and then the domain is automatically expanded in accordance with the repeated process. In order to verify the validity of the criterion for the AED scheme and the applicability of the AED scheme, two‐dimensional incremental plane‐strain forging process is first analyzed using the proposed scheme with various criteria and full domain. In addition, three‐dimensional incremental radial forging process is analyzed to verify the applicability of the proposed scheme to a practical incremental forging process.

The purpose of research was to work out manufacturing technology of plane rim from 2618A aluminium alloy based on hammer forging process.

It was assumed that the manufacturing process consists of die hammer forging and machining. The first stage of the research works was based on designing of the forging process and on numerical simulations in which finite element method was used. On the basis of calculations results, analysis of deformation parameters in the drop forging was made and the rightness of the worked out technology was verified. The second stage of the research works concerned experiments conducted in industrial conditions. Forging dies were constructed and the forging process of a series of drop forgings was carried out. Next machining was done to obtain finished parts.

The conducted research works on the forging process on hammer of the rim drop forging from 2618A aluminium alloy showed that the application of this technology allows for obtaining the product of good quality. Manufactured rims were destined for exploitative research works, aiming at getting certificate that would allow for their implementation in planes.

The rim is being prepared for implementation in small planes of considerably large wheels load.

The presented hammer forging method of plane rim has not been used so far. In the case of applying the rims in planes building, not only industrial plants with large forging presses but also forgeries with die hammers will be able to produce these parts.

The purpose of this study is to reduce the cracks, pores and unfused defects in arc welding, improve the crystalline structure of the weld, refine its grains and improve the mechanical properties.

Taking E690 marine steel as the research object, the experiment adopts a new process method of laser forging coupled arc welding. Welding for comparative experiments. Experiments show that the “V”-shaped groove arc welding process has a larger fusion area, but has pores, the arc current is 168 A, the arc voltage is 28 V and the welding speed is 600 mm/min.

It can be seen from tensile tests that the coupling welding process has the highest tensile strength and yield strength, 872 MPa and 692 MPa, respectively, and the fracture elongation is 29.29%. The single-beam laser forging coupled arc welding process has a distance of laser and wire of 6–8 mm, a laser wavelength of 1,064 nm and the highest weld fusion ratio. The microhardness test shows that the average hardness of single-beam laser forging in the weld zone is 487.54 HV, which is 10.30% higher than that of arc welding. The average hardness in the fusion zone is 788.08 HV, which is 14.52% higher than that of the arc welding process.

The originality of the experiment: proposed a new process method of coupling arc repair for offshore steel forging; adopted a new process method of simultaneous coupling of single-beam short-pulse laser, double-beam short-pulse laser and arc welding; and obtained effect of pulsed laser and arc composite repair on porosity and fusion of E690 marine steel welds.

The purpose of this research is working out of a new forming technology of flat parts with ribs from magnesium alloys with the application of a three-slide forging press (TSFP) for the aircraft industry.

New possibilities of forming aviation parts with ribs gives the application of a prototype TSFP. This press consists of three moveable tools and has wider technological possibilities than typical forging machines. It was assumed that this machine (press) application would allow for obtaining ribbed flat forgings from magnesium alloys of good functional and resistance qualities. A characteristic feature of such forgings forming is the working movement of two side tools, which upset the billet in the form of a plate; the result of their action is forming of one or more ribs in the plane central part. It is possible to use the upper punch to form appropriate rib outline. Theoretical research works based on simulations by means of finite element method were conducted for three cases of the process: semi-free forging of parts with one rib, semi-free forming of forgings with two ribs and forging in closed impression of parts with one rib of triangular outline. The first experimental tests were made on a TSFP for the variant of semi-free forging of parts with one rib.

Research results show that there exists the possibility of realization of forming process of parts with ribs according to the conception assumed by the authors. Positive results of theoretical analyses justify the purposefulness of conducting experimental verification for the proposed theoretical solutions of the forging processes of parts with one rib of triangular outline and with two ribs.

Production of flat parts with ribs from magnesium alloys basing on the worked out by the authors’ technology will allow for improving functional and mechanical properties of parts and for lowering their manufacturing costs. At present, such aviation parts are imported to Poland in the form of casts, which are expensive and not always fulfill the requirements. Additionally, large amount of machining at manufacturing of this type of parts generate larger price at their production.

Forging technology of parts with ribs in a TSFP is unique on a world scale. The advantages of this technology are the process material savings and better resistance properties of the formed forgings with ribs than parts obtained in a traditional way.

This paper aims to investigate the possibilities and determination of hot and warm forging of ultrahigh-strength steel 300M and subsequent quenching with accelerated air. Analysis of microstructure and mechanical properties of forged steel 300M focused on investigation of the effect of processing conditions on final properties, such as strength, impact strength and hardness, taking into consideration temperature gradients and within-part strain nonuniformity occurring in forging and direct cooling of aircraft landing gear.

The research involved semi-industrial physical modeling of hot deformation and direct cooling, aided with numerical analysis of both deformation and kinetics of phase transformations on cooling, with process conditions determined on the basis of numerical simulation of industrial process. Examination of forged and quench-tempered samples involved testing mechanical properties (tensile properties, hardness and impact strength) and microstructure.

Three major findings were arrived at: first, assessment of the effects of energy-saving method of cooling conducted directly after forging. Second, tensile properties, hardness and impact strength, were analyzed on the background of microstructure evolution during hot-forging and direct cooling; hence, applied temperature and cooling rates refer to actual condition of the material including varied deformation history. Third, the accelerated air cooling tests were carried out directly after forging with accurately measured and described cooling efficiency, which enabled the acquisition of data for heat treatment simulation with use of untypical cooling media.

The conclusions formulated on the strenght of studies carried out in semi-industrial conditions with the use of model samples, despite strain and strain rate similarity, wait for full-scale verification in industrial conditions. The direct cooling tests carried out in semi-industrial conveyor Quenchtube are of cognitive value. Industrial realization of the process for the analyzed part calls for special construction of the cooling line and provision of higher cooling rate for heavy sections.

The results present microstructure properties’ relations for good-hardenability grade of steel, which is representative of several similar grades used in aircraft industry, which can support design of heat treatment (HT) cycles for similar parts, regardless of whether direct or conventional quenching is used. As they illustrate as-forged and direct-cooled microstructure and resultant mechanical properties, the studies concerning processing the steel of areas of lower temperature are transferable to warm forging processes of medium-carbon alloy steels. The geometry of the part analyzed in the case study is typical of landing gear of many aircrafts; hence, there is the high utility of the results and conclusions.

The direct heat treatment technologies based on utilization of the heat attained in the part after forging allow significant energy savings, which besides cost-effectiveness go along with ecological considerations, especially in the light of CO₂ emission reduction, improving economical balance and competitiveness. The presented results may encourage forgers to use direct cooling, making use of the heat attained in metal after hot forging, for applications to promote environmentally friendly heat treatment-related technologies.

Direct heat treatment typically seems to be reserved for micro alloyed steel grades and sections small enough for sufficient cooling rates. In this light, taking advantage of the heat attained in forged part for energy-saving method of cooling based on direct quenching as an alternative to traditional Q&T treatment used with application to relatively heavy sections is not common. Moreover, in case the warm-work range is reached in any portion of the forged part, effect of direct cooling on warm-forged material is addressed, which is a unique issue to be found in the related studies, whereas in addition to warm forging processes, the results can be transferable to coining, sizing or shot peening operations, where gradient of properties is expected.

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

The prime task of research in hot forging industry is to improve the service life of forging dies. The in-service microstructural changes that may occur in a die during hot forging is expected to significantly affect the service life. The purpose of this work is to analyse the microstructural evolution of double tempered hot forging dies in a real industrial environment, and the correlation of microstructural and microhardness evolution to the in-service wear and plastic deformation.

Specific hot forging tests were carried out on double tempered AISI H11 chromium tool steel for 100, 500 and 1,000 forging strokes. Macro analysis was conducted on die cross section to analyse the wear and plastic deformation at different stages of forging cycles. Microhardness and microstructural analyses were performed on the die surface after these forging tests.

The macro analysis on the transverse section of dies shows that wear is predominant during initial forging strokes, whereas plastic deformation is observed in later stages. Microstructural analyses demonstrate that during first 500 forging cycles, carbide population decreases at 63 per cent higher rate as compared to corresponding drop during 501 to 1,000 forging cycles. Additionally, the carbide size increases at all stages of forging cycle. Further, microstructural images from dies after 1,000 forging strokes show clustering and spherodisation of carbides by which the “blocky”-shaped carbides in pre-forging samples had spherodised to form “elongated spherical” structures.

The findings of this work can be used in hot forging industries to predict amount of wear and plastic deformation at different stages of service. From the results of this work, the service life of double tempered H11 hot forging dies used in forging without lubrication is within 501 to 1,000 forgings.

Most of the literatures are focussed on the cyclic softening of material at constant temperature. This work analyses the microstructural evolution of double tempered hot forging dies in a real industrial environment and correlates the microstructural and microhardness evolution to the in-service wear and plastic deformation.

An optimisation method for design of intermediate die shapes needed in some forging operations is presented. The basic problem consists of finding an optimal two‐step forging sequence by automatically designing the shape of the preforming tools. The optimisation problem is defined based on an inverse formulation. The objective function of the optimisation problem is a function describing the quality of the obtained part by measuring the die underfill. The finite element method is used to simulate the forging problem. The optimisation method is based on a modified sequential unconstrained minimisation technique and a gradient method. The sensitivity‐dependent algorithm requires computing the derivatives of the objective function with respect to the design variables defining the preform shapes. A direct differentiation method has been developed for this purpose. The optimisation scheme is demonstrated with two axisymmetric forging examples in which optimal preform dies are obtained.

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.

Describes simulations of impact forging processes. Uses the explicit time integration finite element method, which is based on direct time integration of equation of motion, to compute the deformation of the workpiece and the dies. Uses the program developed to simulate the copper blow test performed on a 350,000J counter‐blow hammer. The calculated result reveals a good agreement in the final deformed configurations between the experiment and the explicit simulation. In order to compare this with the explicit method, the implicit time integration rigid‐plastic finite element program considering the inertia effect is also applied to the copper blow test simulation. As a result of the copper blow test simulation using the explicit program and the implicit program, finds that the calculated results have good agreements in available plastic deformation energy, forging load and equivalent plastic strain distribution. Finally, applies the developed program to simulations of multi‐blow forging processes. Presents three major findings from the multi‐blow forging simulations: (1) the continuous analysis technique used for the multi‐blow forging simulations works well; (2) the blow efficiency and the forging load generated by blow operations can be analysed efficiently and simulated results coincide with previous experimental and analytical ones; (3) the geometrical configuration of the workpiece is closely related to blow efficiency.