37Mn5 钢厚壁石油套管在调质处理后发现表面裂纹,利用SEM、EDS及TEM等手段进行了裂纹成因分析和工艺改进试验研究.结果表明,钢管表面的裂纹是因为钢中非金属夹杂物、淬火应力集中和高温回火脆性等因素耦合作用的结果,夹杂物在轧制过程中诱发了微裂纹的产生,在淬火内应力的作用下微裂纹得到进一步扩展延伸,再加上高温回火脆性降低了材料的韧性,最终在钢管表面形成一定深度的宏观裂纹.石油套管采用改进的亚温淬火工艺处理后,可以在基本不降低材料强度的前提下,明显提高冲击韧性和抗断裂失效能力,抑制高温回火脆性,基本杜绝了表面开裂现象,取得了良好的生产应用效果.

采用正交试验方法来确定经济型低合金超高强度45CrNiSiMnMoVA钢的最佳热处理工艺,采用扫描电镜、透射电镜和万能材料试验机等研究了淬火温度、淬火保温时间、回火温度和回火保温时间等因素对试验钢显微组织和力学性能的影响.结果表明:回火温度的极差值最大,是对试验钢力学性能影响的最主要因素,淬火温度的影响次之;试验钢最佳的热处理工艺为:920℃x45 min淬火+350℃x 120 min回火,此时,试验钢的组织为均匀细小的回火马氏体,抗拉强度为1745 MPa,屈服强度为1549 MPa,伸长率为7.3％,室温冲击吸收能量为19.1 J,实现了强度、塑性和韧性的良好匹配.

The effects of different tempering temperatures on the microstructure evolution and mechanical properties of the new low-alloy ultra-high-strength 45CrNiSiMnMoVA steel after quenching were investigated by mechanical property tests, SEM and TEM. The results show that a complex phase organization consisting of martensite/ lower bainite of the tested steel after treated at 920°C×1h+(320~380)°C×4h was obtained, and the partition interface of the lath martensite bundle became blurred from clear with the increase of tempering temperature; In the proposed tempering temperature range, the toughness of the alloy has become better while maintain the strength without decreasing basically, and when the tempering temperature is 350°C, the alloy has the optimal comprehensive mechanical properties of strength, plasticity and toughness together. The analysis concluded that the strong toughening of the tested steel was mainly attributed to the coupling effect of the alloying elements in the steel and the composite toughening of the nano-precipitated phases, among other aspects.

采用力学性能测试、扫描电镜(SEM)、透射电镜(TEM)等研究了不同热处理工艺对新型低合金超高强度45CrNiSiMnMoVA钢的微观组织和力学性能的影响.结果 表明:随着奥氏体化温度的不断升高,试验钢的力学性能逐渐提高,并在920 ℃时达到峰值,达到峰值之后才会缓慢下降;在320～380℃回火后,试验钢的强韧性随回火温度变化的幅度非常小,当回火温度为350℃时,试验钢具有强度、塑性和韧性相配合的最优综合力学性能.分析认为,试验钢的强韧化机理与以"多相、亚稳和多尺度"为核心思想的M3组织性能调控理论十分吻合.

A new kind of mistuning—pre-tightening mistuning was found in the bladed disk based on the engineering practice.The characteristics of bladed disk with pre-tightening mistuning and stiffness mistuning was compared and analyzed based on a continuous parameter model of bladed disk,and the effect of pre-tightening mistuning on the vibration response localization of bladed disk was researched.The result shows that pre-tightening mistuning can make vibration response localization appear in bladed disk as well as stiffness mistuning.Sometimes,the vibration response localization of bladed disk is more sensitive to stiffness mistuning than to pre-tightening mistuning.Compared with stiffness mistuning,the pre-tightening mistuning could not change the natural characteristics of bladed disk.As a result,the pre-tightening mistuning can not be detected by traditional method,such as the frequency test.The result could not only complete the study content of bladed disk,but also conduct the design and manufacture of bladed disk.

The studies on vibration localization of periodic structure are mainly based on displacement modes at present, while the strain modes have not been applied to the research of vibration localization. Consequently, it was imagined to apply the strain modes to vibration localization based on a finite element model of bladed disk with shrouds, and the vibration localization factors based on strain modes and displacement modes were compared with the condition that the bladed disk is mistuning. The results show that the vibration localization based on strain modes is much more sensitive to stiffness mistuning than the vibration localization based on displacement modes; what＇s more, the strain mode shapes are different with the displacement modes at the same mode order. The results are important to the design of periodic structure with snubbing mechanism.

In order to avoid the defect of slow convergence and "immature convergence" existed in the traditional genetic algorithm,the simple genetic algorithm's selection operator and mutation operator were improved.Then piezoelectric network was optimized based on improved genetic algorithm,the ratio of control effect to cost was separately analyzed when each circuit parameter has two values or four values.The results show that compared with the tuned piezoelectric network,bladed disk vibration is suppressed better under the control of a mistuned network which each circuit parameter has two values or four values,and the network which each circuit parameter has two values is more economical.The convergence of improved genetic algorithm is faster and the optimizing result is global.The vibration suppressed effect of the mistuned piezoelectric network is affected by the mistuned value of the blade stiffness.

It's inevitable to the change of effectual area and the collision of every cylinders,so the tremendous concussion to load is easilable in the course of hoist.The question of concussion is a difficut matter in the phylogenesis,so it's mostly to ensure the model of concussion and athletics to the hoisting cylinder.

Based on the different feeding methods,Comparison test study of four methods use is ex-pounded in the block electrode reverse machining the micro-rods in EDM,and the influences of the differ-ent feeding methods to the results are analyzed.Then a micro-rod is made by one of these methods.

In hobbing or modification of the workpiece with CNC gear-hobbing machines,the selection of the right presetting cutter coordinates will have a bearing on the workpiece machining accuracy,the difficulty level of CNC programming. For axially heteromorphic gears with CNC gear-hobbing Machine(gear taper small,drum-shaped gear),the right presetting cutter coordinates calculation was studied.

Based on Pro/ENGINEER,3D solid body model,virtual assembling,dynamic simulation,interference checking and kinematical simulation,and stress analysis can be done for the working devices of loading equipment,and the virtual sample design can be successfully realized for them as well.The provided method is also valid for the virtual sample design of other engineering machinery.