Forming method of axial micro grooves inside copper heat pipe

The high-speed oil-filled ball spinning and drawing process was put forward to manufacture the axially grooved heat pipe with highly efficient heat-transfer performance, and the forming mechanism of micro-grooves inside the pipe was investigated. The key factors influencing the configurations of micro-grooves were analyzed. When the spinning depth varies between 0.4 mm and 0.5 ram, drawing speed varies from 200 mm/min to 450 mm/min, rotary speed is beyond 6 000 r/min and working temperature is less than 50 ℃, the grooved tubes are formed with high quality and efficiency. The ball spinning process uses full oil-filling method to set up the steady dynamic oil-film that reduces the drawing force and improves the surface quality of grooved copper tube.     

Remotely controlled laser welding of tube-to-tube plate joints in the manufacture of heat exchangers

The results of investigations and design studies for the introduction of advanced highly efficient welding processes to the production cycle of manufacture of heat exchanger systems are presented. The optimum parameters of remotely controlled laser welding of tube-to-tube plate joints made of stainless steel and titanium and copper alloys are determined. Specialized equipment for laser welding of the tube-to-tube plate joints is constructed.     

铁路钢轨接续线爆压冷焊技术

介绍了利用爆压冷焊技术研制开发的一种新型的“爆压冷焊式钢轨接续线技术”的设计原则、设计方案，焊接效果及技术性能。     

加氢换热器角焊缝密封接头焊接工艺参数优化

利用有限元软件ABAQUS,开发了一个顺次耦合的角焊缝焊接热应力计算程序,研究了加氢高压换热器板式焊接密封接头应力场的分布;以此数值模拟结果为基础,结合正交试验设计方法,分析了焊接电流、电弧电压、焊接速度及预热温度4个工艺参数对焊接残余应力场的影响,找到一组使焊接残余应力最小的最优焊接工艺参数.结果表明,焊接速度对焊接残余应力的影响最大,该角焊缝焊接残余应力的最高值集中在焊缝和热影响区附近.研究结果为优化加氢高压换热器板式焊接密封的焊接工艺,预防焊接密封接头的开裂失效提供了理论基础.

Abstract：

Using the finite element analysis software ABAQUS, a sequentially coupled fillet welding thermal-stress program was developed to calculate the stress distribution of plate sealing joint in the high pressure hydrogenation heat exchange. Based on the numerical solutions and the orthogonal method, the influence of four welding parameters including welding current, welding voltage, welding speed and preheating temperature on residual stress distribution was analyzed and a group of optimal welding parameters were obtained, which provided a reference for preventing the failure of fillet weld sealing joint in the high pressure hydrogenation heat exchange.     

钯合金膜激光密封焊接工艺研究

采用脉冲激光焊的方法,对厚度为0.04 mm的Pd-40Cu合金膜进行了密封焊接工艺研究,通过试验,确定了焊接的工艺参数,样件经气密性检测和氦质谱检漏达到了使用要求。通过对焊接接头切片观测,接头成形良好,无气孔、裂纹等缺陷,表明脉冲激光焊可用于高纯氢净化器中透氢膜材的焊接。     

异种材料及复合热源搅拌摩擦焊

在对接和搭接方式中,异种材料搅拌摩擦焊相较于同种材料分别具有一些额外的焊接参数,并且对搅拌头材料也有更苛刻的使用要求。总结近年来异种材料搅拌摩擦焊的研究现状,介绍异种材料搅拌摩擦焊过程中脆性金属间化合物的生成及其对焊接接头的力学性能产生的影响。从金属流动机理和数值模拟方面,研究金属间化合物的生成和成长规律,给出针对金属间化合物可能的解决方法。针对高熔点焊材,介绍复合热源搅拌摩擦焊技术、常用的辅助热源以及复合热源搅拌摩擦焊在异种材料搅拌摩擦焊方面的优点和研究的不足之处。     

微通道换热器扁管与集流管焊接关键工艺改进

针对微通道换热器用扁管与集流管连接处炉中钎焊焊接工艺进行了研究,根据相关钎焊理论及试验数据,对现有扁管槽结构进行了改良。采用改良的扁管槽结构,焊接质量得到了显著提高,扁管基本不再紧贴扁管槽一侧,降低了焊缝尾部缺陷率,平均缺陷率由20%降低为:中间段焊缝缺陷率小于等于2%,固定端焊缝缺陷率不高于5%。焊缝成形良好,降低了泄漏风险,保障了焊接品质。此外,在焊接试验的基础上,对焊接缺陷产生原因及改良机理进行了分析。     

石油钻杆形变热处理摩擦焊工艺

对石油钻杆37CrMnMo管体和42CrMoA管接头进行了形变热处理摩擦焊接,对接头金相组织和力学性能分析检测.结果表明,接头完全淬火区晶粒度达到8级,不完全淬火区窄且其被形变区完全覆盖,回火后不完全回火区组织为回火索氏体＋铁素体或碳化物过分长大的回火索氏体;管体和管接头热影响区的硬度最大下降幅度分别仅为6.9%和4....     

铜管接头冷挤镦工艺及模具设计

文中指出了采用冷挤镦工艺代替切削加工生产铜管接头的优点。对铜管接头进行冷挤镦工艺分析、制订冷挤镦件图计算毛坯尺寸及冷挤压镦力。介绍了管坯制备处理及冷挤镦模具结构设计。     

焊接热输入对纯铜焊缝组织及其力学性能的影响

在纯铜(T2)钨极氩弧自动焊(TIG)条件下,研究了不同焊接热输入对焊缝成形、焊缝显微组织及力学性能的影响。结果表明:焊接热输入过大,焊缝正面出现咬边,焊缝反面过宽、余高过高,而焊接热输入过小焊缝未焊透,轧制时易出现根部裂纹;随着焊接热输入的增大,焊缝区以及热影响区晶粒尺寸都增大,接头塑性降低;焊后未轧制时,焊接热输入越大,接头强度越低,而轧制后,焊缝的抗拉强度没有明显的变化,焊接热输入小时的屈服强度明显高于焊接热输入大时的屈服强度,并且接头断裂均发生在焊缝熔合线区,说明熔合线区是整个焊接接头最为薄弱的环节。     

管道全位置自动封底焊设备及工艺研究

针对长输管道自动焊接过程中封底焊环节效率较低,严重制约自动焊高效率的问题,研制完成了一种自动封底专用焊机。介绍了具有离穿透力的组合脉冲熔化极焊接电源的特点,采用工业控制机结合多轴控制器的全位置控制技术,以及以无间隙组对为核心的单面焊双面成型的工艺技术。试验证实,这是一种与长输管道自动焊配套的经济实用型成套设备,具有较好的推广应用前景。     

Controlling heat input in non-consumable electrode arc welding

Analysis of the existing heating force control modes at non-consumable electrode arc welding of groove faces is carried out. Methods and experimental investigation results allowing for determining application field of the arc attitude positioning due to changing characteristic of its inherent magnetic field at non-consumable electrode argon-arc welding by current up to 200 A are covered.     

换热器管子与管板焊接接头残余应力数值模拟

利用有限元软件ABAQUS,对换热器管子与管板焊接残余应力进行数值模拟,获得了焊接接头残余应力的分布规律,比较了伸出角接头和内角接头的优劣.计算结果表明,内角接头残余应力比伸出角接头小.最大径向应力出现在管板表面的热影响区,对管板表面裂纹有主要影响.最大环向应力出现在焊缝根部,对管子与管板连接失效影响较大.相邻两换热管之间,由于后面换热管的焊接加热作用,使前面管子焊缝局部应力值下降,有利于降低应力腐蚀开裂的敏感性.研究结果为优化换热器管子与管板的焊接工艺、控制残余应力提供了理论依据.     

Using friction welding for producing heat exchanger equipment from martensitic 15Kh5M steel

The results of mechanical and other types of tests of metal of welded joints in pipe blanks of 15Kh5M martensitic steel, produced by friction welding with rotation, are presented. On the basis of the analysis of the test results it is concluded that 15Kh5M can be efficiently welded by friction welding and that the method can also be used for producing the tube–tube plate sections of heat exchangers made of 15Kh5M steel with appropriate modernization of welding equipment.     

铝合金搅拌摩擦焊时焊接速度与热输入的关系

与熔化焊时热输入和焊接速度成反比不同,搅拌摩擦焊时焊接速度与热输入的关系非常复杂.文中从摩擦产热和金属塑性变形产热出发,研究了搅拌摩擦焊时焊接速度与热输入的关系,以及相同旋转速度与焊接速度比值时焊接速度与性能的关系.结果表明,在搅拌摩擦焊时,焊接速度与热输入不呈线性关系,而是呈现复杂的形态,焊接速度在不同的参数范围对热输入的贡献是不同的.在相同的旋转速度与焊接速度比值时,随焊接速度的增加,热输入和接头力学性能的关系也不是线性的.所以不能用旋转速度与焊接速度的比值来衡量热输入的大小.     

Elevated temperature strain softening characteristics of 12Cr1MoV steel friction welding pipe joints

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双金属复合管焊接工艺研究与应用

为了提高20#碳钢基管+316L不锈钢内衬管双金属复合管的焊接一次合格率以及生产效率,研究了该材质的焊接工艺参数,并采用该参数进行焊接工艺试验,评定合格后进行了工程应用.结果表明,该工艺焊接工序步骤简单,焊接一次合格率由不到70%提高至90%以上,提高了工程焊接效率,确保了工程顺利投产.     

Effect of heat treatment on microstructure and properties of single crystal copper cold-welded joints

With the means of electron backscattered diffraction (EBSD), mechanical properties test and digital eddy current metal conductivity, the single crystal copper cold- welded joint was tested and analyzed, the structure change of cold- welded joint and the effect of heat treating on the structure and property of cold- welded joint were discussed. The results show that: The deformation area of the single crystal copper cold welded joint is broken, the crystalline grain at the interface of the joint is refined, and the single crystal structure is still maintained in the base metal area. The hardness of the deformation area increases greatly, the conductivity of the joint does not change much, and the tensile strength of the joint reaches about 70% of that of the base metal. At the interface of the heat treating joint, the single crystal structure of the deformation area and the base metal area are destroyed, and the grains grow up at the interface and the orientation is different. The hardness of the joint interface is much lower than that of the non-heat treating joint, the electrical conductivity of the joint is good, and the tensile strength of the joint is higher than that of the base metal.     

多功能焊接热模拟软件的研制与应用

成功研制出多功能焊接热模拟软件,该软件以实测和经典的数学模型为基础,应用Labview8.2和STEP 7进行编程.用该软件绘制焊接热循环曲线,操作界面简单易行.针对多道次焊接热模拟试验设计的道次间隔时间参数,可以保证试验时每一个道次的初始温度与设定值相一致,有效地改善了以往焊接热模拟试验的不足.软件凭借其稳定性、可靠性、快捷方便性,应用于国产MMS系列热力模拟实验机,完善了国产热力模拟实验机的功能,进一步拓宽了其应用领域.     

A physical simulation of longitudinal seam welding in micro channel tube extrusion

Micro channel tube is a newly developed type of aluminum profiles with sub-millimeter-diameter ports in the cross-section designed for heat transfer enhancement. Micro channel tube is formed with porthole extrusion die, and the longitudinal seam welding problem is the key issue related to both the design of the delicate mandrel in the extrusion die and the pressure bearing capacity of the tube. This paper proposes a novel method to evaluate the seam welding strength of the micro channel tube at the stage of extrusion die design. First, a finite element (FE) simulation of the tube extrusion process is performed for the seam welding conditions in the die chamber and effect of the welding chamber height on hydrostatic pressure. Then, a thermo-mechanical experiment is carried out for a quantitative relationship between the welding strength and the weld condition parameters. Combining this relationship to the numerical results, the welding strength under different die design can be evaluated. Pressure bearing tests on the tube prove the reliability of this evaluation method. This study quantitatively connects the seam welding strength of the profile to the extrusion die parameters, which is helpful for optimizing the design of the extrusion process.