AISI 304不锈钢的车削加工

针对AISI 304奥氏体不锈钢的特点,分析了AISI 304不锈钢材料的物理性能和切削加工性能,从刀具材料、切削用量和冷却液的选择等方面研究了AISI 304不锈钢车削加工的影响因素,通过合理选择和优化相关参数等方法有效解决了AISI 304不锈钢的加工难题,获得了较好的车削加工效果,提高了生产效率。     

AISI 304不锈钢高速铣孔测温实验研究

为揭示立铣刀磨损、破损机理,本文采用课题组自主研发的嵌入式刀柄系统,对难加工金属AISI 304不锈钢进行了不同冷却方式、铣刀转速和铣刀直径等变切削参数的测温实验研究,结果表明:主轴转速10 000 r/min时,由干式切削变为湿式切削最高切削温度可下降246℃;在相同刀孔比(1∶1.5)干式铣削时,?12 mm铣刀比?20 mm铣刀测温点最高温度高500℃;湿式切削加工质量较高,圆柱度均小于0.02 mm,尤其是在深孔铣削加工时,内冷铣削优势更趋明显,为高速内冷铣削方式的推广应用提供参考。     

硬切削AISI 440C不锈钢切削力建模及试验分析

利用四种不同形状的刀具,采用多因素正交试验的方法,对四种不同硬度的AISI440C不锈钢进行干硬切削。基于多因素正交回归方法,建立了AISI44C不锈钢的切削力经验模型,并对方程进行了显著性检验。通过对方程的研究,分析了切削参数对切削力的影响。     

涂层硬质合金刀具切削奥氏体不锈钢切削力的试验研究

通过四种涂层硬质合金刀具切削奥氏体不锈钢1Cr18Ni9Ti的试验,研究了切削用量对切削力的影响,并对四种刀具的切削力进行了对比分析。试验结果表明:在采用小进给量、小背吃刀量切削时,出现了背向力大于主切削力的现象;随着切削速度的增加,YBC251、GC2025刀具的切削力先减小后增大;同型号的PVD涂层硬质合金刀具与CVD涂层硬质合金刀具相比较,前者的切削力显著小于后者。     

AISI 304不锈钢铣削加工刀具磨损实验研究

AISI 304不锈钢具有低导热性和高韧性等特性,切削加工性较差。研究采用复合涂层硬质合金铣刀,对AISI 304不锈钢进行了端铣实验研究,考察后刀面磨损情况。实验表明,进给率对磨损的影响大于切削速度。针对刀具后刀面磨损,给出了相对较好的切削条件组合。     

陶瓷刀具切削奥氏体不锈钢的切削力试验研究

对3种复合陶瓷材料刀具切削奥氏体不锈钢(1Cr17Ni7)进行研究,建立了正交切削试验方案.通过试验研究了切削用量对三向切削力的影响,利用指数回归分析建立了3种刀具的主切削力经验公式,并结合切削用量显著性分析对主切削力进行了对比分析.试验结果表明在采用较小进给量和较小切削深度进行切削时,会出现了背吃刀力大于主切削力的现象；切削速度及进给量对主切削力的影响最大；3种刀具中CT2刀具的主切削力最大.     

水室封头材料加工切削力试验及预测模型研究

水室封头作为核电设备的主要零部件,长期处在高温、高压、高辐射等恶劣的工作环境下,材料为高强度钢508Ⅲ钢,具备高强度和高温的力学特性,导致其切削加工性差。在水室封头重型切削加工过程中,大多采用硬质合金刀具进行切削,铣削过程中刀具受到较大的机械冲击和温度影响。针对切削过程中刀具失效严重、换刀频繁等问题,进行水室封头材料加工切削力试验及预测模型研究。通过对水室封头材料进行单因素铣削试验,探讨切削用量与切削力的关系;进而采用正交试验的方法分析切削参数对切削力影响的显著程度,应用回归分析方法建立切削力预测模型,并进行验证。研究结果为进一步研究水室封头材料加工刀具失效机理、切削参数优化及刀具设计开发提供一定的试验基础和技术支持。     

切削参数对316H不锈钢切削力影响的仿真研究

316H不锈钢由于其低热导率、高强度、高延展性和高加工硬化的特性,使其切削加工较为困难。为了探索切削三要素对切削力的影响规律,建立了车削316H不锈钢仿真模型并运用正交仿真实验进行研究。使用了极差分析法和方差分析法分析,并最终得到了影响切削力主次顺序的不同切削参数,给出了最小切削力下的最合理的切削参数。     

应用经济型数控车床研究不锈钢车削力和加工质量

应用经济型数控车床加工SUS304不锈钢,研究切削过程中刀具各个方向受力以及零件加工表面的粗糙度分布趋势。采用单因素试验方法设计车削力试验,并记录加工过程中的切削力以及对应参数下获得的零件表面粗糙度。研究发现,不锈钢切削时,切削力和粗糙度都随着主轴转速增加而略有增大,随着进给量和切削增加而明显增大,并且切削力和粗糙度之间存在弱负相关关系,两个指标都与材料去除率呈正比例变化。     

700℃服役8万h后析出大量σ相AISI 321不锈钢的再利用

以在700℃服役8万h后因组织中析出了大量σ相而报废的AISI 321不锈钢为对象,对其进行不同工艺的固溶处理,研究了固溶处理前后的组织和高温力学性能,并重点关注了固溶处理后组织和高温力学性能的恢复情况。结果表明:固溶处理可以使σ相溶解消失;在1 050℃固溶处理2h后,报废不锈钢的组织和高温力学性能得到很好的恢复,并符合行业标准规定的性能要求,该处理工艺为报废AISI 321不锈钢组织和性能恢复的最佳工艺。     

Influence of ultrasonic vibrations on side milling of AISI 420 stainless steel

Characteristics of one-dimensional ultrasonic-assisted side milling of AISI 420 stainless steel have been investigated in this paper. Cutting force in ultrasonic-assisted milling (UAM) has been modeled, and new relations for critical cutting speed and undeformed chip thickness have been presented. Based on analytic relations, it can be inferred that in successive end mill revolutions, contrary to conventional milling (CM), cutting forces in UAM have different magnitudes. In order to experimentally investigate the cutting forces and the workpiece surface roughness, CM and UAM processes have been applied and compared in certain cutting conditions. Experimental results indicate that the average of cutting forces in UAM is less than in CM, and depending on cutting parameters, workpiece surface roughness in UAM can improve. During small value of feed, the influence of ultrasonic vibrations on the decrease of cutting forces is more noticeable in up milling, while during larger feed, employing UAM is more effective in down milling. It seems that for low feed rates, high cutting speeds and up milling process, the effect of ultrasonic vibrations on the surface roughness is more noticeable.     

高速切削AISI4340钢的切削力有限元分析

在高速硬切削时,切屑主要为断屑,了解断屑引起的高频交变的切削力的特征,有助于优化切削参数.通过有限元方法对AISI4340钢高速直角切削进行仿真.研究切削速度、背吃刀量和刀具前角等切削参数对断屑的形成频率、平均单位切削力以及切削力的频率的影响.分析结果为优化切削参数、减少高速切削中的振动和提高表面加工质量等提供指导.     

水蒸气冷却润滑切削304不锈钢的试验研究

为实现304不锈钢的绿色切削,以过热水蒸气作冷却润滑介质,用Al2O3-TiC复相陶瓷刀具对304不锈钢进行单因素切削试验.试验结果表明:与干切削相比,用过热水蒸气冷却润滑切削时主切削力减小了6％ ～17％,加工表面硬化程度降低了3％～6％,并具有较高的加工表面质量.根据试验结果和冷却润滑作用机理分析可知,过热水蒸气具有较好的冷却润滑作用,且廉价无污染,有望实现304不锈钢的绿色切削.     

Evaluation of micro-drilling technologies for metal-injection-molded 420 stainless steel

Metal-injection-molded (MIM) 420 stainless steel is a commonly used material for high-value products such as fuel injector nozzles. However, the trade-offs involved in using different micro-drilling processes on this material are not well-documented in literature. This article presents a micro-drilling study of MIM 420 stainless steel using four candidate processes: micro-electrical discharge drilling (micro-EDD), ultrasonically assisted micro-EDD, micro-mechanical drilling (micro-MD), and ultrasonically assisted micro-MD. The micro-EDD results shows that the use of ultrasonic vibrations significantly improves the overall process time, spark erosion efficiency, and material removal rate of the process. However, this improvement comes at the expense of increased tool wear and surface roughness, especially while machining under high-discharge-energy conditions. The micro-MD results show that the use of ultrasonic vibrations is beneficial in lowering the thrust force, drilling torque, and tool wear at chipload values greater than the minimum chip thickness of the material. However, the ultrasonic vibrations do not have a notable effect on the surface roughness or on the size of the exit burrs. The results obtained from this study have been used to develop a Likert-type comparison scale to enable application-specific selection of micro-drilling processes for MIM 420 stainless steel.     

Influence of temperature on the fretting response between AISI 301 stainless steel and AISI 52100 steel

Fretting of AISI 301 stainless steel sheet in contact with AISI 52100 steel from 20 °C to 550 °C in air and argon has been studied. Transitions in the mechanical properties of 301SS and oxidative behavior of this pair have been identified as a function of temperature. Strength and ductility of 301SS is reduced from 20 °C to 250 °C, increasing susceptibility to fretting damage. Steady state friction decreases as temperature increases, reducing cyclic stresses. Wear resistance increases in this temperature range, increasing fatigue damage due to the increase in fatigue life associated with increased wear. This study aims to identify the causes of the transitions in behavior and determine the net outcome of the competing effects with regard to fatigue damage.     

Extended octree for cutting force prediction

Prediction of cutting force plays an essentially important role in the selection of optimum cutting parameters and investigation of cutting mechanisms. In this work, an extended octree is presented to represent the workpiece and tool swept volume to acquire the cutting depth and cutting width with high precision so that the cutting forces can be predicted precisely. The algorithm of acquisition of cutting width and cutting depth in flat-end milling is described. A framework of cutting force prediction based on virtual machining was established and a demonstration system was developed consequently. The simulated values of cutting width and cutting depth show good consistency with the theoretically calculated data.     

Workpiece temperature rise during the cutting of AISI 4340 steel

Temperature rises in workpieces were measured during the cutting of various hardnesses of steel by a ceramic tool. Thermocouples were embedded in a specially designed workpiece for the temperature measurement. This workpiece provided practical and accurate positioning of the thermocouples and it allowed the acquisition of reliable data from the cutting experiments. The effects of the workpiece hardness and cutting speed were examined and analyzed. The relationships between the workpiece temperature rise and residual stresses or structural change in a machined surface layer were discussed.It is concluded that the temperature rise in a steel workpiece during cutting by a ceramic tool is so low that it is less likely to cause any surface damage under normal conditions.     

Surface roughness and cutting force prediction in MQL and wet turning process of AISI 1045 using design of experiments

This paper presents an investigation into the MQL (minimum quantity lubrication) and wet turning processes of AISI 1045 work material with the objective of suggesting the experimental model in order to predict the cutting force and surface roughness, to select the optimal cutting parameters, and to analyze the effects of cutting parameters on machinability. Fractional factorial design and central composite design were used for the experiment plan. Cutting force and surface roughness according to cutting parameters were measured through the external cylindrical turning based on the experiment plan. The measured data were analyzed by regression analysis and verification experiments were conducted to confirm the results. From the experimental results and regression analysis, this research project suggested the experimental equations, proposed the optimal cutting parameters, and analyzed the effects of cutting parameters on surface roughness and cutting force in the MQL and wet turning processes.