Applied Mechanics and Materials Vols. 633-634

Abstract: This paper proposes a method of mechanical performance prediction of cold rolled ribbed steel bars based on RBF network with dividing variable space according to original materials’ tensile strength. It builds a sample variable space partitioning model according to the original materials’ tensile strength. It also studies the performance prediction of cold rolled ribbed steel bars based on the 4-in & 1-out RBF network and the performance prediction of cold rolled ribbed steel bars based on the 4-in & 2-out RBF network. The results show that this method can reliably predict the mechanical performance of cold rolled ribbed steel bars, and the predictive effect of the 4-in & 1-out RBF network model based on dividing variable space according to original materials’ tensile strength is superior to the 4-in & 2-out RBF network model.

Abstract: Due to the optimization problem of coating thickness uniformity for two times spray technology, an optimization method of coating thickness uniformity for two times spray technology was proposed based on the optimized spray trajectory of one time. Based on the established tool model and complex curved surface was partitioned into several plane patches, the model of coating thickness was established for two times spray on the plane. The optimization model of coating uniformity was given and the golden section method was used to solve it. Simulation result show that the feasibility and availability of optimization model; the coating uniformity was improved effectively after optimization for two times spray trajectory.

Abstract: Coiling temperature of hot rolled strip is one of the important parameters which affect performances of hot rolled strip. The control of coiling temperature is highly nonlinear and time-varying. Based on the laminar cooling control system of a hot rolling plant, a coiling temperature prediction model based on BP neural network was established. Many factors which affect coiling temperature control were taken into account, and the BP neural network was trained by actual production data. The simulation was carried out, which indicates that coiling temperature can be predicted precisely, and the BP neural network model has the prospect of online application.

Abstract: In the process of modern mechanical parts production, such as parts surface dust, metal powder, coating will appear "nodules" and "burr", easy to fall off small pit of coating surface. So, to ensure the quality of electroplating products plating, to carry out the study on substrate surface treatment before plating technology of plating is very meaningful.

Abstract: Through the analysis of superfine deep-hole drilling process, we used the combination of gun drill and BTA deep-hole drilling process for 17-4PH (0Cr17Ni4Cu4Nb) stainless steel deep-hole drilling test. We measured wall thickness point by point, and calculated the conversion of the eccentricity in a deviation axis line. Which fully embodies the advantage of this process for stainless steel 17-4PH, and provides a new method in super hardness material deep-hole drilling field.

Abstract: In this paper, the ram of boring and milling machining center is taken as the research object. A new method that hydraulic pull rods compensation is proposed to solve the problem of deformation compensation of long stroke ram of boring and milling machining center. Firstly, the method of finite element analysis is used to get the laws of ram deformation and the relationship curve between the ram deformation and the stroke of ram. Secondly, the preliminary calculation value of pull rods compensation force is derived based on the theoretical analysis of material mechanics. The relationship curve between compensation force and the stroke of ram is obtained by finite element analysis and polynomial least squares method. Finally, the analyzed results are as follows: the laws of ram deformation distribution is accurately predicted by the used method, the deflection error of the ram is well controlled,and the machining precision is significantly improved.

Abstract: SPC method is a process controlling tool with the aid of mathematical method. Define, Measure, Analysis, Improvement and Control is the implementation processes of quality management. Combined with the two methods, the quality fluctuation in the production process could be controlled effectively and qualified products rate could be enhanced excellently. In this paper, the film thickness problem of motor shell coating production line has been studied based on statistical process control and DMAIC processes. The Pareto diagram, cause and effect diagram, operation chart are used to inspect production defects in the process. At same time, the factors leading to product defects are determined. Then, DOE method is applied to find the best parameters of electrophoresis coating process. SPC method is adopted to monitor the improved film thickness. The results show that quality level of coating process has improved greatly.

Abstract: Superalloys have a high tensile strength at elevated temperature, a good stability and reliability in a large range of temperatures. Among these superalloys, GH4169 is widely used as thermal components in the turbojet engine. Traditional welding methods are difficult to adapt to the development of high-tech manufacturing. Laser welding plays an important role in superalloys welding field increasingly for its advantages. In this investigation, superalloy GH4169 plate with a thickness of 1mm was welded utilizing the pulsed laser welding and the mechanical properties of the laser welded joints are analyzed. The maximum tensile strength is 928 Mpa, which is close to the base material tensile strength. The welded joint can meet the requirements of users.

Abstract: Structure and pass system of Y-type mill which have three-roller is analyzed. A hot rolling method to produce magnesium alloy bars through flat triangle-arc triangle-round pass system is put forward. Using Deform-3D software, the rolling process of AZ31 alloy bar is simulated to determine the parameters of the rolling process and die. The experiment verifies that the hot rolling process is feasible. The organizational structure is analyzed with metallographic microscope, and the results show that dynamic recrystallization is occurred, the grain size is obviously refined, and the mechanical property of the material is improved in hot rolling process.

Abstract: Aim at the bending and upsetting process of a kind of crankshaft, this paper analyze the technical difficulty and treatment measures during the process. The metal flowing and the defects easily occur during the deformation are visual reappeared by the FEM, moreover, the influence of the thickness of flash and the size of fillet on the quality of crank is also analyzed. Takes the crank as an object, the experiment of bending and upsetting deformation is carried on, which verified the accuracy of the simulation result, and finally, the crank is qualified with fullness deformation, continuous fiber without collapsing or folding. The product with this process can satisfied all the specification of the technology.