石油钻采装备用40CrNiMoA钢的冲击性能

针对石油钻采设备的低温服役条件,分别考察了石油工业常用40CrNiMoA钢的冲击性能以及热处理工艺、毛坯尺寸和温度等因素的影响。冲击试验结果表明,40CrNiMoA钢的冲击性能在试验温度范围内随温度降低而逐渐下降,并且在- 40℃～-20℃内发生韧-脆转变。在常规热处理条件下,毛坯尺寸对40CrNiMoA钢的冲击性能具有显著影响,在本试验条件下,试样的冲击性能随着取样毛坯尺寸的增加而显著降低。此外,热处理制度对40CrNiMoA钢的力学性能也有重要影响,适当提高回火温度有利于改善40CrNiMoA钢的冲击性能。冲击断口分析表明,断口存在大量碳化物和氧化物颗粒及其脱落后而形成的孔洞,这是导致冲击性能降低的重要原因。     

“零保温”淬火对20SiMn2MoV钢冲击性能的影响

研究了“零保温”淬火对20SiMn2MoV钢冲击性能的影响.实验表明,常规热处理制度下,20SiMn2MoV钢的低温冲击韧度不满足API-8C标准,而“零保温”淬火温度为910～950℃时,其冲击韧度及拉伸性能均满足标准要求.“零保温”淬火温度为870～950℃时,随淬火温度的升高,20SiMn2MoV钢试样的冲击韧度逐渐升高；与常规的热处理工艺相比,“零保温”淬火试样的晶粒度要高出一个等级,这是材料具有优良强韧性的主要原因.     

变质Cr12MoV模具钢热处理工艺研究

研究了热处理工艺对变质Cr12MoV钢组织和性能的影响。结果表明，淬火回火处理后，变质Cr12MoV钢中共晶碳化物呈粒状均匀分布；随淬火温度的升高，硬度先升后降，冲击韧度呈逐渐升高趋势；淬火后试样随回火温度的升高，硬度逐渐降低，冲击韧度先降后升；确定变质Cr12MoV钢最佳热处理工艺为1080℃淬火＋250℃回火。     

提高射孔器零件冲击韧度的热处理工艺改进

就20SiMn2MoV钢制射孔器淬火+低温回火后,零件低温冲击韧度不足的现象进行了原因分析.不均匀的马氏体组织、过高的淬火加热温度会导致淬火组织细密均匀程度降低,从而降低钢的低温冲击韧度.由此对原热处理工艺进行改进试验.结果表明,经两次正火+淬火处理后,可使晶粒细化;适当降低淬火温度,通过调整淬火冷却介质和控制淬火冷却时间,获得一定数最下贝氏体和低碳马氏体的混合组织,能够显著提高20SiMn2MoV钢零件的低温冲击韧度.     

淬火温度对压裂泵液压缸用钢动态断裂行为的影响

采用示波冲击试验、扫描电镜观察断口等方法研究了压裂泵液压缸用30CrNi2MoV钢动态断裂行为。本文使用三种热处理工艺(相变点上下淬火(780、830、880℃)+620℃回火)进行试验。结果表明:与锻态试样相比,热处理后试样冲击性能得到大幅度提升,30CrNi2MoV钢的冲击功随淬火温度的升高而先升高后降低,其裂纹韧度K_(IC)/σ_(yd)随淬火温度的增加而降低,抗断裂能力变差,但强度增加。断口观察表明,锻态试样断口为脆断,具有解理形貌,780、830℃淬火试样断口呈现韧窝+部分撕裂棱的断裂特征,880℃淬火试样断口呈现韧窝特征。     

淬火温度对30Cr2Ni4MoV钢组织和性能的影响

为了解淬火温度对30Cr2Ni4MoV钢显微组织和力学性能的影响,对尺寸为φ100 mm×200 mm的试棒分别从780℃、820℃和860℃油淬随后640℃回火,检测了钢的显微组织和力学性能。结果表明:①不同温度淬火随后回火的30Cr2Ni4MoV钢的组织均为回火索氏体和残留奥氏体;②较低温度淬火、640℃回火的钢,马氏体呈条带状;③随着淬火温度的提高,钢的组织逐渐均匀化,由条带状转变成等轴状,其硬度和强度增加,冲击吸收能量下降。此外,扫描电镜检验表明,经调质处理的30Cr2Ni4MoV钢冲击试样断口有大量的韧窝,也有细小撕裂棱,基本为韧性断裂。     

铁素体含量与回火温度对HSLA钢组织性能的影响

研究了不同铁素体含量与回火温度对HSLA钢组织与力学性能的影响。结果表明:热轧HSLA钢从810～900℃淬火后组织为马氏体和37%～0%铁素体,且随淬火温度升高,铁素体晶粒尺寸减小,可动位错密度增加;高温回火后板条马氏体分解严重,位错密度降低并有大量碳化物析出;铁素体含量增加使屈服强度和抗拉强度降低,其中抗拉强度在450℃回火后下降约200 MPa,而屈服强度随回火温度的变化趋势决定于铁素体含量;180℃回火后铁素体与马氏体间的强度差使铁素体对拉伸性能和冲击性能表现出不同的断裂机理;450℃回火后铁素体与马氏体能够协调变形,伸长率与冲击吸收能量均随铁素体含量增加而提高。此外,均匀的马氏体有利于提高试验钢的低温韧性,其-40℃冲击吸收能量119 J。     

加工条件与毛坯尺寸对35CrMo钢低温冲击性能的影响

针对石油钻采设备的低温服役条件,考察了石油工业常用35CrMoA钢及ZG35CrMo铸钢的冲击性能以及热处理工艺、毛坯尺寸和温度等因素的影响。冲击试验结果表明,35CrMoA钢的冲击性能在试验温度范围内随温度降低而逐渐下降,并且在0～-30℃范围内发生韧-脆转变。在常规热处理条件下,毛坯尺寸对35CrMoA钢的冲击性能具有显著影响,特别是在室温及不太低的温度（-200C～20℃）下,取自中等尺寸（Ф130mm）毛坯的试样表现出较好的冲击性能;而取自较小尺寸（Ф60mm）及较大尺寸（Ф220mm）毛坯的试样冲击性能明显降低,反映出热处理过程中适中的冷却速度有利于改善钢的冲击性能。铸钢ZG35CrMo的低温冲击性能,特别是在-40℃～-60℃之间与35CrMoA钢相差不大,表明加工状态（轧制或铸造）对冲击性能的影响可能主要表现在室温及其以下部分温度区间。值得注意的是,当温度从-20℃下降至-60℃时,铸钢ZG35CrMo冲击性能的下降幅度远小于35CrMoA钢。此外,在各个相应试验温度下,35CrMoA钢及铸钢ZG35CrMo的冲击断口特征基本相同。     

回火温度对低合金超高强钢Q1300组织与性能的影响

为开发出屈服强度1300 MPa级的超高强度工程机械用钢,研究了回火温度对Q1300超高强钢组织和性能的影响规律。结果表明:淬火态钢板经220℃低温回火后,由于淬火应力消除和晶内ε碳化物的析出,试验钢的规定塑性延伸强度和低温冲击性能提高,硬度和抗拉强度下降;当回火温度高于250℃时,板条间的薄膜状残留奥氏体开始析出碳化物,降低晶界结合能,恶化试验钢的冲击韧性,回火温度为450℃时试验钢的冲击性能最差,此后继续增加回火温度,试验钢的冲击性能不断提高;当回火温度在200～300℃范围内变化时,试验钢的规定塑性延伸强度基本保持不变,此后随着回火温度增加,试验钢的规定塑性延伸强度逐渐下降。试验钢在250℃回火时,可以获得最优的力学性能,规定塑性延伸强度1381 MPa,抗拉强度1571 MPa,断后伸长率(A_(25)) 10. 6%,半尺寸试样-40℃的冲击吸收能量达到50 J。     

回火时间对高温轴承钢组织和性能的影响

研究了500 ℃高温回火处理时不同回火时间对高温轴承钢组织和性能的影响规律。结果表明,随回火时间的延长,高温轴承钢的强度和硬度逐渐增加,而钢的塑性和冲击性能逐渐降低。回火时间的延长促进了试验钢中第二相的析出和长大,由于第二相的析出强化,使得钢的强度和硬度提高。冲击断口韧窝中析出相的数量随回火时间的延长逐渐增加,且尺寸有所增大,冲击断口中典型韧窝形貌逐渐减少,断裂机制逐步由韧性撕裂向准解理断裂转变。试验钢在500 ℃100 h长时间回火后有少量μ相析出,μ相的析出使钢的塑性降低。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.