Papers by Keyword: Forging

Abstract: Based on Deform-3D software, a 3D rigid-plastic FE model of forging forming process was established, then simulation analysis effective strain distribution, temperature distribution and load-stroke curve of three kinds of intermediate slabs (S1,S2,S3) in forging process. The results show that the optimized intermediate slab (S3) of effective strain distribution and temperature distribution is most homogeneous. And the maximum load force is minimum, the Shapes and dimensions of forging reach the preset value.

Abstract: The generation III nuclear technology (AP1000) has been introduced into China since 2006 along with the project of 1000 MW advanced passive pressurized water reactors which is a development of any of the generation II nuclear reactor designs incorporating evolutionary improvements in design developed during the lifetime of the generation II reactor designs. The low pressure rotor of nuclear turbine for AP1000 is currently the heavy forging which requires the use of the heaviest steel ingot and possesses the maximum weight and cross sectional area in the world. The forming and manufacturing technology of such heavy forging have been described in this paper.

Abstract: Magnesium alloy is known for its light weight and high strength. Due to the desirable properties, Magnesium alloy is required in the fields such as transportation from the energy-saving point of view. The development of forming methods is especially highly expected. In order to manufacture productions of high dimensional accuracy with good surface finish without defects, it is important to evaluate tribological characteristics of forging of Magnesium alloys. In this paper, the friction coefficients were measured by the ring compression test. It compresses a ring specimen between parallel tools and is the method for the friction coefficient by the rate of change of the inside diameter. The friction coefficients of several kinds of Magnesium alloys have been evaluated depending on temperature, compression speed, and the kind of the lubricant here.

Abstract: This paper presents the experimental research results concerning a new method of forming of brackets with a triangular rib. The forging process of products with ribs was conducted applying a three-slide forging press (TSFP) on material model in the form of lead plates. During the experiment, the influence of the process particular parameters on the obtained products quality was analyzed. On the basis of the research results the main failure modes of the material during processing were determined. The limiting value of the plate upsetting coefficient depending on its length was given. Considering conducted research works, it was stated that it is possible to form such brackets forgings in TSFP in accordance with the worked out method.

Abstract: Parts having a strength distribution were produced from tailor friction-welded billets consisting of steel bars having different quenchabilities. Chrome steel SCr420 and mild steel S25C bars having high and low quenchabilities, respectively, were joined by friction welding. The tailor friction-welded billets were forged, and then quenched so as to have a strength distribution. The cold formability of the tailored billet was first examined from simple compression in the normal and tangential directions to the joint. No cracks appeared even for an 80% reduction in height in the compression. In a tensile test of the 80% reduced billet, the softer S25C side was fractured and the interface was not fractured. The tailor billets have enough cold formability. The thermal influence around the joint of the tailor friction-welded billets was eliminated by annealing, and thus inhomogeneous deformation around the joint in forging was prevented. A shaft having a high strength flange and a connecting rod having high strength and machinability were produced by forging and quenching of the tailored billet.

Abstract: A significant factor in the cost of industrial machinery for precision forging is the maximum load required to fully forge the final shape of components. Typically in a precision forging process, the required load increases greatly towards the end of the stroke. This study focuses on reducing the final sharp increase in load encountered in a typical closed die forging setup. A technique of reducing the peak load in the forging of gears is proposed, named the Peripheral Relief (PR) method. A gear forging tool set has been designed and manufactured. A number of experimental trials have been performed using model materials to investigate the force reduction technique. An efficient and simplified FE model has been developed to evaluate the effects of the PR method. The experimental load characteristics are compared to the simulated results. The method has been found, both numerically and experimentally, to significantly reduce the peak load encountered at the end of the forging stroke compared to current closed die forging techniques.

Abstract: In this study, A356 aluminum thin plates (1.2 mm thick) are fabricated using the semi-solid forming process. Using the electromagnetic stirrer, A356-based semi-solid slurry is fabricated. The configuration of the thin die cavity for forging is designed using the fluid analysis of MAGMA software. The dimension of the thin plate is 150 x 150 x 1.2 mm. The semi-solid slurry with 45% solid fraction is created and then injected into the forging die at the 200-ton hydraulic press for compression. Thin plate with semi-solid slurry at 45% of the solid fraction (fs) is fabricated with punch speed of 300 mm/s and punch pressure of 200 MPa for compression the slurry. The formability, mechanical properties and microstructure of a formed thin plate sample are analyzed. As a result, a thin plate with 211.5 MPa of tensile strength and 8.5% of elongation can be formed.

Abstract: For the production of forged components, it is necessary to coordinate and optimize the production stages along the different process chains. This includes the mainstream processes as well as the associated process chains and the respective processes of die manufacturing. Until now, these processes and process chains are commonly planned and optimized independently due to different and often contradictory target criteria. This paper deals with an extended approach to a holistic planning and optimization of forging process chains by means of the optimization technique Genetic Algorithm (GA) in order to reduce production costs and time.

Abstract: The review and some experiences are given from measurement and evaluations of residual stresses on large shaft forgings and rail axles using the hole-drilling and ring-core strain-gauge methods, provided by Pilsner Research and Testing Institute, Czech Republic.

Abstract: Cold welding, e.g. by cold forging, is a smart manufacturing technology, enabling novel multi material designs. A material combination, which is particularly attractive for manufacturing, though challenging to handle in a cold welding process, is steel and aluminum. We investigate the bond formation between cold forged C 15 (mainly primary heat treated) and AW 6082. Analysis starts with numerical simulations using the finite element analysis (FEA) to identify optimum conditions for bond formation. The bond strength was determined by tensile tests from samples eroded from the cold-welded specimen. Best performing samples showed a maximum tensile strength of ~200 MPa with ductile failure in the AW 6082. Transmission electron microscopy (TEM) inspection of the bonded area between aluminum and steel show a reaction layer consisting of iron and aluminum of few nm thickness throughout the sample. The formation of such a reaction layer is hypothesized to be crucial for bond formation.