1Cr12Ni2W1Mo1V不锈钢表面等离子堆焊司太立熔覆层的组织及性能

为提高1Cr12Ni2W1Mo1V不锈钢的耐水蚀性能,采用等离子堆焊方法在其表面制备司太立熔覆层。研究了涂层的显微组织和显微硬度分布,分析了涂层的抗微粒冲蚀性能和耐水蚀性能。结果表明:司太立熔覆层与基体材料冶金结合良好,熔覆层组织细小、分布均匀,基体为枝晶状Co-Cr固溶体,枝晶间较均匀地分布着黑色碳化物,主要为M7C3和少量WC颗粒;司太立熔覆层的平均显微硬度(382.38 HV4.9 N)约为基材平均硬度(195.29HV4.9 N)的1.96倍,最高硬度值达到了421.00 HV4.9 N;堆焊第2层的硬度明显高于第1层的;司太立熔覆层合金的抗微粒冲蚀性能优于基材,其水蚀速度比基材小,在基材1Cr12Ni2W1Mo1V上堆焊司太立合金能有效提高其耐水蚀性能。     

Constitutive modelling for high temperature behavior of 1Cr12Ni3Mo2VNbN martensitic steel

The deformation behavior of 1Cr12Ni3Mo2VNbN martensitic steel in the temperature range of 1253 and 1453 K and the strain rate range of 0.01 and 10 s⁻¹ are investigated by isothermal compression tests on a Gleeble 1500 thermal-mechanics simulator. Most of the stress-strain curves exhibit a single peak stress, after which the stress gradually decreases until a steady state stress occurs, indicating a typical dynamic recrystallization (DRX) behavior of the steel under the deformation conditions. The experimental data are employed to develop constitutive equations on the basis of the Arrhenius-type equation. In the constitutive equations, the effect of the strain on the deformation behavior is incorporated and the effects of the deformation temperature and strain rate are represented by the Zener-Holloman parameter. The flow stress predicted by the constitutive equations shows good agreement with the experimental stress, which validates the efficiency of the constitutive equations in describing the deformation behavior of the material.     

4Cr14Ni14W2Mo钢中的碳化物

本文研究了4Cr14Ni14W2Mo 钢中碳化物的性态,溶解和析出规律及其对性能的影响。指出,该钢中存在球形、立方体形和六方柱体形等多种形态碳化物,但均为 M_(2(?))C_6。较低温度时效析出的碳化物为立方体形,细小弥散,与基体共格,有明显强化作用。未溶碳化物和较高温度二次固溶后析出的碳化物多为球状和六方柱体形,尺寸较大,与基体不共格,强化作用有限。二次固溶沿晶界择优析出的粗大链状碳化物和时效沿晶析出的网状碳化物易导致沿晶断裂。     

电磁场对高速钢与45钢感应摩擦焊接的影响

利用电磁场对金属材料产生的"场致效应",调节摩擦焊接表面的温度场,以改善异种金属摩擦焊接组织及性能.研究了外加电磁场对W6Mo5Cr4V2高速钢和45钢摩擦焊缝显微组织、合金元素扩散及焊接接头力学性能的影响.结果表明,摩擦加热阶段施加电磁场使45钢近缝区铁素体的数量减少;而在顶锻阶段施加电磁场,使45钢侧铁素体数量有所增多.同时,在顶锻阶段施加电磁场作用时,主要合金元素C、Cr、W的扩散区宽度明显增大.在顶锻阶段采用较短的电磁场施加时间和较低的感应电流强度,可以提高W6Mo5Cr4V2高速钢和45钢摩擦焊接头的抗拉强度.     

Hot workability of 00Cr13Ni5Mo2 supermartensitic stainless steel

The hot workability of 00Cr13Ni5Mo2 supermartensitic stainless steel was investigated by hot compression and hot tension tests conducted over the temperature range of 950–1200 °C and strain rates varying between 0.1 and 50 s^?1. The processing map technique was applied on the basis of dynamic materials model and Prasad instability criterion. Microstructure evolutions, Zener–Hollomon parameter as well as hot tensile ductility were examined. The results show that, as for the hot working of 00Cr13Ni5Mo2 supermartensitic stainless steel in the industrial production, the large strain deformation should be carried out in the temperature range 1140–1200 °C and strain rate range 0.1–50 s^?1, where the corresponding Zener–Hollomon parameters exhibit low values. Moreover, when deformed under high strain rate range (above 15 s^?1), the deformation temperature can be reduced reasonably.     

ICP-OES法测定高速工具钢中钨、铬、钒、钼

采用ICP-OES法同时测定高速工具钢中钨、铬、钒、钼元素的含量。讨论了基体、分析谱线对测定结果的影响,并确定了最佳的测定条件。最后利用精密度和统计学中的t检验分析测定数据的准确与可靠性。结果表明此方法方便快捷,测量数据准确可靠。     

3Cr2W8V钢形变热处理研究

3Cr2W8V钢广泛应用于有色金属热锻、热挤压和压铸成形.为进一步挖掘3Cr2W8V钢的使用潜力,提高模具材料综合使用性能和使用寿命,本文开展了针对该钢的形变热处理研究,讨论了形变温度、冷却方式及回火温度对试样组织与性能的影响.研究表明高温形变热处理不适宜于3Cr2W8V,形变后水冷优于空冷,并得出组织性能俱佳的优化形...     

10Cr4Ni4Mo4V钢和Cr4Mo4V钢的特性与断裂行为

对１０Ｃｒ４Ｎｉ４Ｍｏ４Ｖ钢和Ｃｒ４Ｍｏ４Ｖ钢的特性与断裂行为进行了试验研究。结果表明,１０Ｃｒ４Ｎｉ４Ｍｏ４Ｖ钢经微氮渗碳热处理后,其表面硬度、残余应力、断裂韧性及裂纹扩展速率均优于Ｃｒ４Ｍｏ４Ｖ钢的。     

Precipitation in 9Cr–1Mo steel after creep deformation

The carbides present after creep testing a 9Cr–1Mo steel at 566 °C over a range of stress levels giving rupture times of up to 7300 h have been characterized and identified using a transmission electron microscopy, energy-dispersive X-ray spectroscopy and electron diffraction. The initial carbide precipitates present were M₇C_3, (NbV)C and VC and it was determined that M₆C carbide precipitates were present in all specimens after elevated temperature exposure for greater than approximately 1700 h. No precipitation of M₂₃C₆ was detected. The evolutionary sequence from the initially present carbides during high temperature exposure involved the formation of the stable M₆C carbide directly, without the intermediate formation of M₂₃C₆, as is reported to occur in other Cr–Mo steels.     

4Cr14Ni14W2Mo 钢的内氮化动力学

本工作导出了紧靠氮化物层下方发生的内氮化过程的动力学方程,方程也可用于双层内氮化过程。按此方程所设计的方案在氨气介质中对4Cr14Ni14W_2Mo 钢进行氮化实验,得到与预期相一致的结果。较高的氮化温度和较高的氨气分解率可免除该钢种的氮化层剥落。     

施加氮化钛铝涂层对1Cr11Ni2W2MoV不锈钢力学性能的影响

采用电弧离子镀技术在马氏体热强不锈钢1Cr11Ni2W2MoV样品表面沉积了氮化钛铝涂层，研究了涂层对不锈钢的高温拉伸强度、持久断裂时间以及常温旋转弯曲疲劳寿命的影响。Ti0.7Al0.3N涂层的施加对高温拉伸强度影响不大，高温持久实验表明，Ti0．7Al0．3N涂层显著延长了材料的持久断裂时间；Ti0.7Al0.3N和Ti0．5Al0．5N涂层均使试样的疲劳寿命提高约20％左右；高温持久时间和常温旋转弯曲疲劳寿命的提高与涂层制备过程中高脉冲偏压轰击下不锈钢表面形成的一层结构均匀、组织致密的表面强化层的，以及涂层中的压应力的存在。     

热强马氏体不锈钢1Cr12Ni3Mo2VA钢最佳热处理工艺的优化研究

阐述了１Ｃｒ１２Ｎｉ３Ｍｏ２ＶＡ马氏体不锈钢经不同温度回火的组织，碳化物的析出及位错结构。研究表明，采用１０５０℃保温６０ｍｉｎ空冷＋６５０℃保温２ｈ空冷能获得优良的综合性能。     

Experimental and numerical investigation on thermal fatigue behaviour of 9Cr 1Mo steel tubes

Boiler tubing is subjected to alternate cycles of heating and cooling during operation initiating alternate thermal expansion and contraction. Alternate cycles of differential expansion and contraction causes thermal fatigue of the component. Thermal fatigue causes tube failures, significantly reducing the working life of the tubular components. Boilers have matured into super critical design using T91 grade materials thereby increasing the operating efficiency. The studies involving thermal fatigue of tubes of T91 grades for boiler components in operating conditions are thus an important area. A simple experimental set up has been developed to simulate thermal fatigue conditions in the internal diameter (ID) side of the tube. The work involves both experimental and numerical investigations of the thermal fatigue behaviour by creating a simulated environment and a Finite Element Model (FEM). FEM analyses are carried out based on the decoupled thermal and inelastic stress analyses to compute the total plastic strain range experienced by the boiler tubes. The cyclic spray cooling causes thermal fatigue cracks in the T91 tube. The number of cycles to crack initiation has been obtained from the experimentation and number cycles to failure has been calculated using modified Coffin-Manson relation. The study thus presents a reliable fatigue failure analysis of 9Cr 1Mo steel tubes used in boiler industry.     

Effects of shot peening on fatigue properties of 0Cr13Ni8Mo2Al steel

Abstract

The influence of shot peening on the fatigue properties of 0Cr13Ni8Mo2Al steel has been studied. Changes in surface roughness, surface topography and residual compressive stress field were determined by experiments. The experimental results show that shot peening improves the fatigue property and the fatigue crack sources are pushed to the region beneath the hardened layer. Low Almen intensities should be used when 0Cr13Ni8Mo2Al steel is shot peened because of its sensitiveness to the surface roughness.     

The interaction of N with atomically dispersed Ti, V, Cr, Mo, and Ni in ferritic steel

Since long, the nitriding process has been used to improve the mechanical properties of the surface of steel. However, results from the prevailing model for the nitriding of steel are still not in perfect agreement with experimental data. It is investigated if this can be attributed to the model assumption that there is no interaction between nitrogen atoms and alloying atoms in solution in the iron matrix. To this end, the interaction of N with atomically dispersed Ti, V, Cr, Mo, and Ni alloying element atoms in ferritic steel is calculated using Density Functional Theory. Results of the Density Functional Theory calculations agree well with experimental lattice parameter, Mössbauer spectroscopy, and internal friction data taken from literature. Deficiencies in prevailing atomistic models for Fe-Me-N configurations in steel (Me denotes the alloying element considered) are revealed and the initial stages of Me_xN precipitation in alloyed iron are elucidated. For all elements but Ti, the interaction with N is negligible or repulsive. Significant attractive interaction exists only if Ti is a second nearest neighbour of N (–0.22 eV). It is shown that this interaction is too small to significantly influence nitriding at typical nitriding temperatures (>500°C ). Consequently, in modelling the nitriding of steel at typical nitriding temperatures, interaction between the atomically dispersed alloying elements and nitrogen can be disregarded. Internal friction experiments evidence nitrogen in solution in the steel bonded with higher binding energy, also for the other alloying elements. We suggest that this nitrogen is bound in Fe-Me-N accumulations consisting of more than one alloying atom and one or more nitrogen atoms. For the modelling of nitriding of steel, these interactions must be taken into account.     

固溶处理工艺对022Cr17Ni12MO2和06Cr18Ni11Ti不锈钢力学性能的影响

通过对两种奥氏体不锈铜022Cr17Ni12MO2和06Cr18Ni11Ti进行不同工艺的固溶处理,研究了固溶温度、保温时间及冷却方式对两种不锈钢材料的抗拉强度Rm、规定非比例延伸强度Rp0.2和RP1.0,以及伸长率A的影响规律。结果表明：相比于空冷,采用水冷方式有利于提高两种不锈钢材料的强度,而冷却方式对两种不锈钢伸长率的影响不明显;随着固溶温度的升高和保温时间的延长。总体上两种不锈钢材料的强度降低,伸长率增加。