成都电焊机研究所科研新成果简介

ZX7—250型逆变弧焊机新研制的ZX7—250型逆变弧焊机是用作手工直流电弧焊的焊接电源。采用调频原理,以交流—直流—交流—直流的方案,得到直流焊接电流。该焊机有以下特点: 1.重量仅33公斤,约为同等容量的旋转直流弧焊机和整流弧焊机的1/11～1/5。 2.额定输入容量小,只有9千瓦,约为同等容量的旋转直流弧焊机和整流弧焊机的     

GM—1000型自动弧焊机

天津市电焊机厂广大革命职工在党的“九大”精神鼓舞下,继 RBC—20000型,RBC—4000型储能点焊机试制成功之后,70年还试制成 GM—1000型自动氩弧焊机。这种焊机可以代替原苏修氩弧、埋弧的两种焊机,在抛帝甩修的道路上迈进了一大步。该焊机电源部份由硅整流元件组成。焊车的速度及送丝速度均采用可控硅进行控制。该焊机可以对8～40毫米铝、铜、铝合金,铜合金等有色金属进行氩弧焊接。更换     

ZS～500型硅整流弧焊机的改进

近年来,我厂硅整流弧焊机的生产有较大的发展,但在焊机性能上还存在一些缺点。通过对硅整流弧焊机的试验考核,发现ZS—500型焊机几乎集中了硅整流焊机的许多“通病”,所以决定改进 ZS—500焊机。     

GM—1000型自动弧焊机

天津市电焊机厂广大革命职工在党的“九大”精神鼓舞下,去年试制成 GM—1000型自动氩弧焊机。此焊机可以代替苏修氩弧、埋弧的二种焊机,在抛帝甩修的道路上迈进了一大步。GM—1000型自动弧焊机的电源部份由硅整流元件组成。焊车的速度及送丝速度均采用可控硅进行控制,其中送丝速度由电弧电压反馈控制。该焊机可以对8—40毫米铝、铜、     

对我厂半自动CO_2焊机的一点改进

几年来,我厂生产的NBC—300、NBC1—500型CO_2焊机,用户反映存在过流继电器起弧时容易误动作,甚至需揿返回按钮起弧等问题,为此,我们进行了分析和试验研究。半自动CO_2焊机采用接触起弧,起弧过     

电弧钎焊设备及工艺研究

本文介绍了一种新型的惰性气体保护下的硬钎焊——氩气保护下的熔化极电弧钎焊,叙述了研制成功的NQA——160型半自动氩弧钎焊机的电气性能、特点及用该机进行的电弧钎焊工艺的研究,同时涉及电弧钎焊的用途和潜力。 NQA——160型半自动氩弧钎焊机及工艺的研究已经通过鉴定。     

一种实用新型CO2弧焊PWM送丝调速系统

介绍了一种利用SG3524芯片设计的CO2弧焊机送丝调速电路。SG3524芯片是一种最常用的性能优良的专用PWM脉宽调制芯片，通过其可实现送丝机通断控制，电枢电压负反馈控制和速度调节控制。较之传统晶闸管调速电路，该电路结构简单，调速性能更佳。通过网压波动试验，电机冷热态变化试验及焊枪阻力试验，验证了该调速电路的可靠性。送丝速度变化率在三种情况下均小于10％，符合JB／T8748—1998，MIG／MAG弧焊机标准要求。该电路已应用于NBC—500KR型焊机上。     

新产品介绍

NBA5—500型推拉式送丝熔化极半自动氩弧焊机1.用途焊机适用于铝及铝合金板部件在离焊机10～12米范围内进行半自动全位置焊接。特别适宜进入构件内部(如船舶、车辆等)进行操作。2.结构特点焊机由 ZPG 2—500型硅焊接整流器、SS—5型送丝机、Q—8型焊枪等组成(图1)。     

BX1—200型便携式交流弧焊机的设计与计算

本文介绍了ＢＸ＿１—２００型便携式交流弧焊机主要参数的设计计算方法，该焊机结构紧凑、重量轻、使用灵活、电流能连续调节，是一种新型的便携式交流弧焊机。     

NSA—300—1型可控硅脉冲稳弧交流氩弧焊机

一用途 NSA—300—1型交流手工钨极氩弧焊机主要用于铝及铝合金的焊接,焊机具有下列特点: 1、焊接电源采用动铁式弧焊变压器,具有陡降外特性,焊     

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).     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.