Materials Science Forum Vols. 800-801

Abstract: 300M ultra high strength steel, a new type of steel with broad prospects for development, has good mechanical properties, and is widely used for manufacture of aircraft landing gear. In order to reveal influence law of cutting parameters on milling force of 300M ultra high strength steel, the influence law of feed rate, milling width, and depth of cut and spindle speed on milling force is firstly studied through the single factor experiments in this paper. Secondly, the influence level of experimental factors is compared by orthogonal experiment. Finally, combined with orthogonal test data and the least square method, the multiple linear regression model of milling force in 300M ultra high strength steel milling is built. The accuracy of the model has been verified well by experimental verification, which has the guiding significance to reveal the milling mechanism and actual production.

Abstract: The new developed carbon fiber reinforced polymer laminates are widely used in main structural components of big commercial aircrafts. Generally drilling is the final operations in manufacturing structure, which is the most important operation during assembly. Defects such as burrs and delamination always appear in the process of drilling, which makes it hard to control the drilling quality. In this research, the drilling defects of T800 CFRP laminates are evaluated by using a brad point drill and a multifacet drill in terms of drilling forces, burr defect and delamination detection. The results show that the spindle speed is the most significant factor affecting the delamination defect followed by the feed rate. High speed drilling and low feed rate could improve the surface quality and reduce the delamination. The multifacet drill showed excellent drilling performance than the brad point drill and generated smaller defects.

Abstract: The W6Mo5Cr4V2 high-speed steel tool was magnetized by an AC magnetization device which made by ourselves, and the cutting experiments were carried out in a general purpose machine with the magnetized high-speed steel tool and non-magnetized high-speed steel tool. The experimental results indicated that the cutting surface roughness of the workpiece could be improved by the magnetized W6Mo5Cr4V2 high-speed steel tool. Meanwhile the magnetization time and magnetization frequency should be regarded as the key of magnetization adjusting parameters. The magnetized W6Mo5Cr4V2 high-speed steel tool presented the different cutting performance under the different magnetization time and frequency, in which there were the better effects in low frequency. In addition, the experimental results also showed that the cutting force could be reduced during the cutting process by using of the magnetized W6Mo5Cr4V2 high-speed steel tool and the formation of the built-up edge in the tool could be inhibited, thereby the tool life was prolonged and the processing quality was improved.

Abstract: High temperature alloy is the key hot end parts' material, which is often used in the modern aircraft, spacecraft and the rocket engines, as well as naval vessels and industry gas turbine. And it's also used in the nuclear reactor, chemical equipment, coal conversion technologies etc. as the very important high temperature structural materials. High temperature alloy of turning processing is the technical difficulties in mechanical cutting work, this paper introduces the high temperature alloy turning processing features, turning processing tool, cutting parameters, the choice of the cutting fluid and machining notice proceedings, etc.

Abstract: Carbon fiber reinforced polymers (CFRP) are increasingly used in aerospace and other industries, due to its high specific strength and stiffness. Machining operations are involved between forming fabrication and assembling as a fining process, during which defects like delamination, burrs and splintering are the main cause of substandard products. This is because that CFRP is a typical difficult to machine material with distinct anisotropy and heterogeneity. Thus machinability of CFRP material under different fiber orientations is a main issue. This paper intensively investigated on cutting forces and temperatures when orthogonal cutting of 0° T700/LT03A CFRP uniform laminates, with fiber orientation from 0°to 180°. Material removal mechanisms and carbon fiber fraction modes under various fiber orientations were discussed. The results showed that fiber orientation of 90°is the worst scenario of cutting, under which condition the force and temperature of the highest level, while that of 150°indicates the other. The results of cutting temperature indicated that it is mainly from the friction heat in the zone III generated by the thrust force.

Abstract: The various feed rate and cutting speed have an important influence on cutting force, tool wear and chip morphology in machining titanium alloy. Cutting experiments are carried out analyzing the titanium alloy Ti6Al4V under different cutting speed and feed rate, the cutting force values are obtained. The analysis results show that the dominant wear pattern is adhesion wear and chipping. And the tool wear also has an influence on chip morphology.

Abstract: This paper will use the Al₂O₃-SiC_w whisker toughening ceramic tool WG300 and Si₃N₄-Al₂O₃ (Sialon) SX9 ceramic tool cutting performance test.Study on different cutting speed, ceramic cutting tool in machining nickel based high-temperature alloy tool life and tool wear mechanism, and analysis of the wear form under different cutting parameters. The test results show that: with the increase of the cutting speed, WG300 and SX9 two kinds of tool durability showed a downward trend, the value of VB is higher than that of Al₂O₃-SiC_w whisker reinforced ceramic cutting tool flank wear of Sialon ceramic cutting tool, but its notch wear value VN is far less than Al₂O₃-SiC_w whisker reinforced ceramic cutting tool,the main failure form of WG300 notch wear, the main failure form of SX9 for the flank wear.

Abstract: Titanium alloy TC25 has been widely used in aircraft industry due to its excellent thermal stability, heat resistance and longer service life. In this paper, cemented carbide tools were applied to carry out orthogonal milling experiments for both titanium alloy TC25 and TC4 with identical cutting conditions. Cutting forces, cutting temperatures and surface roughness were measured to assess the machinability for TC25 and TC4. From the experimental results, the cutting parameters can be optimized to guide efficient machining processing of TC25.

Abstract: Blisks are important components of aircraft engines. Its machining plays an important role in a aerospace industry. Blisk processing efficiency has become a hot topic in the field of machining. Disk milling is a new processing method to achieve efficiency. In order to optimize disk milling process parameters of blisk, the use of full-factor experimental for researching TC4 titanium disc milling process. Analyze the impact of different cutting parameters on cutting force, the results show: during milling titanium by Discal Cutter, with the increasing of feed per tooth, the cutting force increases. But cutting forces in three directions has the different influence. Feed per tooth corresponding with radial cutting depth. In order to guarantee the material removal rate, it can be selected smaller feed per tooth and larger radial cutting depth. Through the stress simulation analysis on the blade, it can be carried out that the maximum strain of blade is concentrated at the tip arc. The equivalent stress is mainly concentrated at the main cutting edge and the tip arc. It can provide the basis for future tool design.

Abstract: As the main method of high efficiency cutting Ni-based superalloy, high-speed cutting can not but intensify the cutting-tool wear for the high cutting force and cutting temperature. So, it is very necessary to study the process of cutting-tool wear and wear mechanism, especially, the effect of cutting-tool wear on the cutting force, cutting temperature and surface roughness of machined workpiece. In this paper, investigation of tool wear in high-speed cutting is proposed, the PCDTiAlN carbide insert is used in the experiment, the cutting-tool wear and the corresponding cutting force, cutting temperature and surface roughness of machined workpiece is detected. It indicates that the cutting force, cutting temperature and surface roughness of machined workpiece is changed corresponding the cutting-tool wear,the wear process of coated tool include the coated material wears and base material wears,the wear mechanism is complex. Key word: superalloy, high-speed cutting, tool wear, wear form ; .