高效热丝GMAW焊接工艺熔敷速率试验分析

交流热丝GMAW工艺是一种高效焊接工艺,其主弧为传统GMAW电弧. 填充焊丝和熔池及母材构成闭合回路,交流脉冲预热电流流经该回路,产生电阻热并预热填充焊丝. 当被预热到高温的填充焊丝进入熔池后,在液态金属作用下迅速熔化. 进行了高效热丝GMAW工艺的试验研究,找到填充焊丝预热电流、填充焊丝伸出长度、焊丝间距、主弧焊接规范等参数之间的匹配规律,实现了20 kg/h以上的熔敷速率. 分析了前述影响因子对熔敷效率的影响规律. 结果表明,热丝GMAW在提高熔敷速率和熔敷系数方面相对传统焊接工艺有明显优势,可以实现高熔敷率低热输入的工艺效果. 该工艺在高强钢大厚板焊接等领域具有广阔的应用前景.     

新型低能量焊接工艺参数对熔敷速度的影响

新型低能量焊接技术(New Low Energy Welding Technology,简称NLE)是一种新型焊接方法,采用推拉送丝方式完成熔滴过渡,焊接过程无飞溅并能有效降低焊接热输入。NLE焊接系统通过电流输出和焊丝运动相互匹配,两者协同工作实现稳定焊接。通过焊接工艺试验深入研究燃弧峰值电流I_1、保持时间T_1、送丝速度v_1、焊丝送进延时时间T_4、焊丝回抽速度v_2及焊丝回抽延时时间T_5等控制参数对焊丝熔敷速度的影响规律。结果表明:随着I_1、T_1、v_1、v_2和T_5的增大,焊丝熔敷速度增大,并且I_1和T_1对焊丝熔敷速度的影响较显著,而v2和T_5对焊丝熔敷速度的影响不明显,随着T_4的增大,焊丝熔敷速度逐渐减小,适当调节焊接控制参数可以有效控制焊丝熔敷速度。     

伊萨ICETM集成冷丝埋弧焊

ICE (integrated cold electrode)集成冷丝埋弧焊是在双丝埋弧焊的基础上增加了一根不导电的焊丝(冷丝),冷丝置于同一个导电嘴中的两根平行的导电焊丝(热丝)中间,利用导电焊丝在焊接过程中产生的电弧热量熔化冷丝,在无需额外增加焊接热输入的情况下达到显著提高焊接熔敷率的埋弧焊接方法.通过伊萨专利技术的控制软件在控制系统中设定冷丝送丝比率以达到与热丝送丝速度的有效匹配,保证焊接过程的稳定性.焊接过程的稳定还得益于伊萨ICE焊枪的设计,即使干伸长度和弧长发生变化也能保证冷丝的熔化点始终在电弧的包围中.ICE具有焊接熔敷率高、焊剂消耗量少、节能环保、焊道成型易控等特点.     

尹萨ICE~(TM)集成冷丝埋弧焊

ICE(integrated cold electrode)集成冷丝埋弧焊是在双丝埋弧焊的基础上增加了一根不导电的焊丝(冷丝),冷丝置于同一个导电嘴中的两根平行的导电焊丝(热丝)中间,利用导电焊丝在焊接过程中产生的电弧热量熔化冷丝,在无需额外增加焊接热输入的情况下达到显著提高焊接熔敷率的埋弧焊接方法。通过伊萨专利技术的控制软件在控制系统中设定冷丝送丝比率以达到与热丝送丝速度的有效匹配,保证焊接过程的稳定性。焊接过程的稳定还得益于伊萨ICE焊枪的设计,即使干伸长度和弧长发生变化也能保证冷丝的熔化点始终在电弧的包围中。ICE具有焊接熔敷率高、焊剂消耗量少、节能环保、焊道成型易控等特点。     

热丝MAG焊接方法的开发与应用

1.前言热丝焊接方法是一种除电弧外,另外添加一根通电焊丝,利用电阻热熔化焊丝,提高金属熔敷率的方法。热丝应要与TIG电弧或等离子弧等非熔化极电弧配合使用。表1为热丝焊接方法的优点。熔化极电弧(例如MAG焊)中添加热丝的方法,到目前为止几乎还没有人进行过尝试,但从我们的实     

交流脉冲MIG焊接铝合金薄板的工艺特性

交流脉冲MIG焊其焊缝熔深及焊丝熔化速度不仅与焊接电流有关，而且与负极性比率有关。当负极性比率等于零即直流且焊丝为正极性的MIG焊时，其焊缝熔深最大，焊丝熔化系数最小，熔敷速度最小；随着负极性比率增加，焊缝熔深减小，同时焊丝熔化系数增加，熔敷速度增加。交流脉冲MIG焊接铝合金薄板时，通过调整焊接电流及负极性比率，形成浅焊缝熔深的同时，形成较高的熔敷速度，从而可以提高焊接速度，避免出现烧穿及熔池下塌现象，保证焊接质量。     

低能量焊接工艺控制参数对熔滴尺寸的影响

低能量过渡焊接技术(Low Energy Transfer Welding Technology,简称LET)是一种新型焊接方法,它采用推拉送丝的方式完成熔滴过渡,焊接过程无飞溅,并能有效降低焊接热输入。LET焊接系统通过电流输出和焊丝运动相互匹配,两者协同工作实现稳定焊接。由于熔滴尺寸直接影响熔敷速度,通过焊接工艺试验,深入研究燃弧峰值电流I_(ap)、保持时间T_(ap)、送丝速度v_(z2)、焊丝送进延时时间T_1、焊丝回抽速度v_(f1)及焊丝回抽延时时间T_3等控制参数对熔滴尺寸的影响规律。结果表明:随着I_(ap)、T_(ap)、v_(f1)、T_1和T_3的增大,熔滴尺寸增大,而v_(z2)对熔滴尺寸的影响不明显,适当调节焊接工艺参数能够有效控制熔滴尺寸。本研究为深入了解LET焊接工艺过程,有效调节焊接熔敷速度奠定了良好的实验基础。     

核电站不锈钢水池热丝自动焊工艺研究

对不锈钢水池热丝TIG自动焊焊接工艺进行了研究,并从微观组织和力学性能等方面对2种方法进行了比较,结果表明:热丝电流的加入可以增加焊丝的熔敷效率,改善焊缝成形,随着热丝电流的增大,焊丝的熔敷效率提高,熔宽增大,余高减小;与常规TIG焊相比,热丝TIG焊由于热丝电流的加入,使得热输入减小,进而使得焊缝中奥氏体尺寸更加细密和均匀,焊缝组织的显微硬度和抗拉强度更优良。     

旁路耦合微束等离子弧热特性及焊缝成形特点

针对传统微束等离子弧焊中焊丝熔敷率与焊接电流不能解耦的局限,提出旁路耦合微束等离子弧焊方法.通过给外填焊丝添加一电流,使焊丝与焊枪钨极间产生一个旁路电弧,实现熔化母材热量与熔化焊丝热量的解耦,确保熔化母材电流稳定的同时提高填充焊丝的熔化速度.对旁路耦合微束等离子弧焊的熔敷率、母材热输入及焊缝成形质量进行试验研究.结果表明,该方法既保持了传统微束等离子弧焊的优点,又在提高焊丝熔敷率的同时降低母材的热输入;并在其它焊接参数保持不变时,随旁路电流的增加,焊缝的熔宽、熔深和稀释率减小,余高和成形系数增大.     

HS-80高强钢焊丝激光-MAG复合焊熔敷金属特性

研究了HS-80焊丝激光-MAG复合焊和MAG焊两种焊接方法的熔敷金属特性.与MAG焊相比,激光-MAG复合焊熔敷金属的屈服强度、抗拉强度和冲击韧度显著提高,熔敷金属的组织更加细小,合金元素过渡系数增大.高速焊接导致的熔池金属冷却速度快及熔池金属流动性的增加是导致复合焊熔敷金属组织细化的主要原因.焊缝金属中Ti,Mo等...     

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.     

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.     

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.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.