T91/P91钢配套焊条CHH717的研制

讨论了影响所研制焊条熔敷金属理化性能的主要因素,尽可能低的S、P、Al等有害杂质含量及合理的合金含量可以得到良好的综合力学性能.经过试验确定了热处理工艺,并通过相变点Ac1的测试得到了印证.试验结果表明,焊条的焊接工艺性良好.熔敷金属的化学成分及力学性能均满足有关标准要求.微观组织观察表明,经760 ℃×2 h回火后其熔敷金属显微组织为回火索氏体.对所研制焊条的熔敷金属进行了625 ℃外推105 h高温持久强度试验,证明此焊条可广泛应用于超(超)临界发电设备用相应耐热钢的焊接.     

合金元素对建筑钢结构用耐火耐候焊丝性能的影响

采用不同成分的Q460 MPa级耐火耐候埋弧焊丝搭配SJ101焊剂进行熔敷金属的焊接,通过冲击试验、高温拉伸试验、电化学腐蚀试验及周浸腐蚀试验研究了合金元素对焊丝熔敷金属冲击性能、高温性能和耐蚀性能的影响。结果表明,Cr促进熔敷金属组织中先共析铁素体的生成,影响冲击韧性; w(Mo)在0.4%以上有助于焊丝满足Q460 MPa级耐火性能要求; Ni-Mo-Cu成分体系的焊丝可以满足与母材匹配的耐蚀性要求。     

焊条电弧焊对2205双相不锈钢焊接接头综合性能影响的研究

采用焊条电弧焊焊接工艺方法焊接2205双相不锈钢,研究了焊条电弧焊对2205双相不锈钢焊接接头组织及力学性能的影响,同时研究了E2209焊条熔敷金属的抗腐蚀性能.研究结果表明:E2209焊条熔敷金属具有优良的抗腐蚀性能;采用适当的焊接热输入,可获得具有合理相比例并且力学性能优良的接头.     

6620型深冷耐蚀镍基特种焊条试制及性能研究

以国外进口同类产品作为参照,通过药皮组成的配方设计,研制了一种6620型深冷耐蚀镍基特种焊条,分别从焊接电弧稳定性、焊接过程飞溅大小、焊后脱渣等工艺性能进行了试验测定。同时结合光学金相、SEM扫描电镜观察及力学性能测试对熔敷金属组织性能作了深入研究。结果表明,所研制的镍基焊条基本与进口产品相当,在焊缝成形及焊后脱渣性能方面优于进口同类产品。对试制镍基焊条焊后所得熔敷金属进行微观组织分析,结果显示,焊条熔敷金属呈现单向奥氏体柱状晶形态,晶粒略显粗大,但总体尚未出现明显粗大化的趋势;所研制的焊条力学性能能够满足标准技术要求。     

ST-I 41DP深熔焊条的研制及应用

通过对焊接熔深与影响因素关系的深入研究,研制成功ST-I41DP深熔焊条.该焊条熔敷金属化学成分及熔敷金属力学性能见表1、表2.ST-I41DP焊条的焊接熔深对比试验及深熔对接焊缝试验结果分别见表3、表4.     

新材料在J422焊条中的研究与应用

通过对焊接结构断裂韧性机理分析,提出如何改善J422焊条熔敷金属综合力学性能和抗裂性,以及综合焊接工艺性能的构思,并研究开发新材料,应用于J422焊条药皮配方设计中,促使产品上水平,降成本,增效益.     

T/P92钢焊接材料的性能测试及钢管的焊接工艺评定

对研制的T/P92钢配套焊接材料进行了常规性能测试,并进行了钢管的焊接工艺评定。熔渣的熔点和粘度参数反映出焊条具有理想的焊接工艺性。采用研制的PP-R727焊条和PP-R72钨极氩弧焊丝焊接的熔敷金属力学性能均可满足标准要求。水银法测得PP-R727焊条熔敷金属的扩散氢含量为2.1 mL/100 g,达到超低氢焊条水平。PP-R727焊条和PP-R72焊丝熔敷金属的A_(Cl)分别为795、814℃。通过斜Y形坡口试验测得PP-R727焊条的冷裂纹止裂预热温度为150℃。焊接工艺评定结果显示,焊接接头各项性能均满足DL/T868-2014《焊接工艺评定规程》要求。     

E5515-G型焊条烘焙温度对扩散氢含量及相关性能的影响

通过改变烘焙温度,研究了E5515-G型焊条烘焙温度对扩散氢含量及相关性能的影响.结果表明,在350～450℃范围内提高该焊条的烘焙温度,将显著降低其熔敷金属的扩散氢含量,同时对熔敷金属力学性能、焊接接头力学性能以及微观组织都没有明显影响.因此,提高E5515-G型焊条烘焙温度,将有效提高焊接接头的抗氢致冷裂纹能力.     

LNG储罐用超低碳不锈钢焊条CHS027LT的研制

介绍了一种超低碳、超低温(-196℃)、高韧性、抗晶间腐蚀的LNG储罐专用不锈钢焊条CHS027LT的渣系选择、配方设计与产品性能。经不同焊接热输入条件下的多种焊接位置工艺性能、熔敷金属理化性能比较与三批次定型焊条产品力学性能稳定性研究,结果表明,在焊接热输入10.2～16.9kJ/cm范围内,该焊条焊接工艺性能优良,熔敷金属理化性能均满足技术要求,三批次定型焊条产品表现出稳定的力学性能,-196℃冲击吸收能量大于50J。熔敷金属微观组织为奥氏体+少量铁素体。     

超低氢型高韧性耐热钢焊条CJR307的研制

通过渣系设计、微合金化设计以及杂质元素控制等研制出超低氢、低杂质含量、低回火脆性以及高韧性的1~1.25Cr-0.5Mo耐热钢焊条CJR307。通过高速摄影对CJR307焊条的电弧和熔滴过渡进行了观察,其焊接电弧稳定、熔滴过渡平稳、飞溅小,焊接工艺性能优异。所研制的焊条熔敷金属扩散氢含量为3.11 m L/100 g,S,P,Sb,Sn,As等杂质元素含量低,Bruscato脆化指数小于11,Watanabe脆化指数小于128.7。熔敷金属在-20℃低温条件下的冲击吸收功平均值大于170 J。     

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。