非熔化极电渣堆焊

非熔化极电渣堆焊不同于熔化极电渣堆焊,有其独特的适用之处。石墨棒、钨棒或水冷铜棒均可作为非熔化极,但是由于水冷铜棒在熔渣里易发生电腐蚀断裂,且使用寿命相对较短,故其使用较少。堆焊时,由于石墨棒和钨棒的氧化和熔化,其尺寸发生变化,应注意熔入熔敷金属的碳和钨。随着非熔化极电渣堆焊的进行,填充金属和熔渣分别熔化,但它们之间相互关联。尤其是当填充金属的送丝速度增加时,也需通过将电极浸入熔渣内,增大堆焊电流,从而增加熔渣池的输入热量。这些反应都将影响金属熔池的形状和熔敷金属的性质。解决这些问题将有效改善非熔化极电渣堆…     

金属材料直接接触加热熔化过程的研究

采用准稳态法对电加热管直接接触加热金属材料的熔化过程进行了研究，获得了金属材料在熔化过程的温度分布、界面移动规律以及电加热管表面温度的变化与表面热负荷的关系，并通过试验验证了电加热管在金属熔化过程中表面温度的变化规律。理论计算结果表明，当电热管加热功率密度较大时，其表面温度和金属材料温度均不会大幅度升高；理论和试验结果的比较表明，电热管表面温度的理论计算结果和试验结果较为一致。     

摩擦堆焊技术研究进展

摩擦堆焊在常规摩擦焊中引人其他形式的运动，拓展了摩擦焊的应用范围。采用摩擦堆焊可以得到大厚度、基本无稀释、组织致密、性能可靠的堆焊层，而且堆焊效率高。该技术在刃具制造、航空材料连接上得到应用。介绍了摩擦堆焊的工艺特点，综述了其研究发展历史，并指出其广阔的应用前景。     

摩擦堆焊工艺参数的优化选择

利用工艺试验分析了工艺参数对摩擦堆焊工艺的影响：随着耗材转速的增加，堆焊层的宽度和厚度均线性减小；随焊敷压力的增加，堆焊层宽度增加，厚度减小。结合热源模型建立了摩擦堆焊工艺参数匹配因数nF(耗材转速与焊敷压力之代数乘积)与摩擦预热时间tp的函数关系。实际应用中，可以根据摩擦预热时间确定工艺参数匹配因数，然后根据各个参数对堆焊层性能的影响，具体确定三个参数，完成工艺参数的优化选择。     

摩擦堆焊技术及其应用

摩擦堆焊可在材料表面获得无稀释、结合完整性高的焊敷层，是一项高效、优质、低成本的堆焊技术．应用该技术对于解决无法采用常规摩擦焊接的大型或异型构件以及难焊材料的焊接与堆焊问题具有应用价值。介绍了摩擦堆焊技术原理、研究进展及其应用。     

大型卷筒熔化极药芯焊丝气体保护焊堆焊工艺

介绍铜管拉拔机关键部件拉拔卷筒孚用熔化极药芯焊丝气体保护焊堆焊耐磨层的堆焊工艺。堆焊材料选用抗裂性好的ＰＫ－ＹＤ２１２焊丝，单层硬度〉ＨＲＣ５０。所确定的堆焊工艺可行，工件不预热，熔合区窄，堆焊合金释稀率低。     

论塑性加工时接触摩擦的应用与摩擦功率与计算

本文阐述了塑性加工时接触摩擦的应用其发展概况，列举了在薄壁杯形件后挤、薄壁圆管反挤，带状薄膜挤压及盒形件反挤等工艺中应用的实例，提出了区分摩擦辅助塑性加工和摩擦塑性加工两种不同性质应用方法的意见，说明了两种应用中摩擦有益功率的计算方法，证明作者在文献〔６〕中所提出的摩擦辅助加工中接触摩擦功率的计算是完全正确的。     

瞬间液相扩散焊过程中的接触熔化与等温凝固模型

接触熔化与等温凝固是瞬间液相扩散焊过程中两个非常重要的阶段,是获得优质连接接头的关键,一直以来也是学术界研究的热点.综述了接触熔化与等温凝固过程的动力学模型,包括接触熔化与等温凝固时间的解析解,接触熔化过程中反应层厚度与连接时间符合扩散控制的抛物线规则,以及等温凝固过程中液/固界面迁移的速度方程.并对现有模型进行了分析和讨论.     

论塑性加工时接触摩擦的应用与摩擦功率的计算

本文阐述塑性加工时接触摩擦的应用及其发展概况，列举了在薄壁杯形件反挤、薄壁圆管反挤、带状薄膜挤压及盒形件反挤等工艺中应用的实例，提出了区分摩擦辅助塑性加工和摩擦塑性加工两种不同性质应用方法的意见，说明了两种应用中摩擦有益功率的计算方法，证明作者在文献［６］中所提出的摩擦辅助加工中接触摩擦功率的计算是完全正确的。     

铜钢异种材料摩擦堆焊工艺优化

摩擦焊是最近几年发展较快的新型摩擦焊接技术之一。国内外学者对铁合金之间的焊接方法研究较为深入,但对铁铜异种材料之间焊接的研究尚不多见。通过大量实验,研究旋转速度为800~1 200 r/min、焊接速度为20~50 mm/min时焊接接头抗拉强度的变化。结果表明,当旋转速度为1 000 r/min、焊接速度为30 min/mm时,铜钢异种材料摩擦堆焊的接头平均抗拉强度是母材强度的89%,并且焊接质量最好。     

Finite difference modeling on the temperature field of consumable-rod in friction surfacing

Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. The temperature field of consumable-rod in friction surfacing, as a kind of thermal processing technology, is an important factor in the successful implementation of the process. In this paper, the heat source model of consumable-rod in friction surfacing is established, by which the temperature field of consumable-rod during the process is simulated through finite difference method. The results are consistent with experiments, reappearing the temperature field of consumable-rod during friction surfacing, thus providing theoretical guidance in the choice for key technical parameters in engineering practice.     

耗材摩擦焊接过程热力耦合分析

以AA6061铝合金为试验对象,基于ABAQUS/Explicit建立耗材摩擦焊三维完全热力耦合模型,分析温度场、等效塑性变形场、轴向缩短量和飞边形状,结果表明,焊接温度低于材料熔点为固相连接,焊接过程塑性金属大量挤出,形成蘑菇头形状的飞边,飞边温度处于480 ℃左右;在稳定焊接阶段,前进侧温度高于返回侧,在垂直于焊缝方向上,焊棒高温区大于焊板高温区,温度分布的不均使得涂层边缘处结合不良. 高温区域趋于稳定后,轴向缩短量和时间呈近线性关系,焊接结束时轴向缩短量为7.5 mm,高温区和塑性变形区都集中在摩擦界面附近的堆积区域.     

Performance analysis of friction surfacing

Performance criteria regarding the material deposition rate and energy consumption per unit of deposited mass were established for the characterization of friction surfacing. These criteria were tested in the friction surfacing of mild steel, for a range of process parameters. The influence of forging force, consumable tilt angle, travel and rotation speeds on interfacial bond properties and process efficiency were investigated. Coatings were examined by optical microscopy, image processing techniques and hardness testing. The applied load on the consumable rod was found to be essential to improve joining efficiency and to increase the deposition rate. Higher rotation or travel speeds were detrimental for the joining efficiency. Tilting the consumable rod along the travel direction proved to improve the joining efficiency up to 5%. For the testing conditions under study, the material loss in flashes represented about 40–60% of the total rod consumed, while unbonded regions were reduced to 8% of the effective coating section. Friction surfacing was seen to require mechanical work between 2.5 and 5 kJ/g of deposited coating with deposition rates of 0.5–1.6 g/s.Deposition rates are higher than for laser cladding or plasma arc welding with a specific energy consumption lower than for other cladding processes.     

Wear behaviour of steel coatings produced by friction surfacing

Friction surfacing was performed to produce multi-layer coatings of AISI 1024, AISI 1045 and AISI H13 over mild steel substrates where a continuous joining was achieved between adjacent layers and between the clad and the substrate. Microscopic and hardness characterization revealed the presence of bainitic and martensitic microstructures which influenced the hardness of the coatings. The study aimed to determine which material combination was more wear-resistant. The analysis suggested that AISI 1024 presents the least wear, both in terms of friction coefficient and wear rate. This is due to the formation of adherent protective oxide layer which is not present in both the AISI 1045 and AISI H13 steels.     

Transferring mechanism of the coating rod in friction surfacing

A coating rod of 1Cr18Ni9Ti (321) was deposited on the substrate of mild steel 1020 to be able to perform a friction surfacing experiment. The temperature changes of special points on the coating rod were measured using a thermocouple. The results show that the temperature increase rate at the friction interface reached a high level at first. Then the rate decreased to a low level once the friction system became quasi-steady and the temperature became approximately stable near the melting point of the coating rod. The theory of contact melting was used to build the physical model for the quasi-liquid layer. Subsequently, the corresponding calculations were carried out. The computer simulation results are found to be consistent with the experiment results, and as such, the present study demonstrates the feasibility of applying contact melting theory to the study of friction surfacing. Likewise, this study reveals that the material at the top of the coating rod is plastic, and that it behaves as a quasi-liquid in the friction surfacing process. The study establishes the theory basis for the study of the mechanism of friction surfacing, and provides a new method for investigating other friction-welding techniques.     

Tool steel and copper coatings by friction surfacing - A thermography study

Infrared thermography was used to record thermal profiles during friction surfacing. Thermal profiles for different sets of consumable rod/substrates (tool steel/steel; copper/steel and copper/copper) were recorded and analyzed. The thermal profiles showed distinct stages of plastic deformation with respect to temperature. The mechanism of bonding or no-bonding was discussed based on thermal profile data. It was found that a metallurgically bonded coating can be obtained if the flow stress of the plasticized material is comparable with the localized stress developed due to axial loading.     

铝/钢多层多道耗材摩擦焊接头组织性能研究

采用耗材摩擦焊实现2A12铝合金在Q235低碳钢上的多层多道焊接。结果表明:耗材摩擦焊可以获得表面成形良好、无内部缺陷的多层多道焊接接头。在焊接热循环作用下,堆焊层组织中第二相颗粒发生了聚集长大且先堆焊层第二相颗粒聚集长大现象更明显;接头后堆焊层硬度高于先堆焊层硬度;接头剪切强度可达130.3 MPa,为2A12铝合金剪切强度的63%,接头断裂于堆焊层铝合金侧,断裂方式为韧性断裂。     

基于ADINA的非局部摩擦模型的数值分析

利用ADINA有限元分析软件,从宏观和细观两方面研究圆柱体镦粗过程中金属材料表面微凸结构对接触区域上的库仑摩擦和非局部摩擦的影响,得到了接触法向应力随压下量的变化关系,及接触面上法向应力和摩擦应力的分布规律。结果表明,在宏观领域内,传统库仑摩擦模型与非局部摩擦模型没有区别;只有在细观领域(考虑表面微凸时),非局部摩擦效应才显现出来。且这种非局部效应与微凸体分布有关。     

槽型堆焊焊条及其堆焊技术研究

研制了一种新型槽型堆焊焊条并探讨了堆焊工艺及其对显微组织的影响,该焊条具有稀释率低,制造简便等优点。金相显微照片和波谱分析结果表明:堆焊层剖面分为热影响区、过渡层、胞状树枝晶层和等轴晶层,成分由亚共晶向过共晶过渡,该组织使涂层具有高耐磨性,可延长堆焊件使用寿命。当焊速增大时,堆焊层中的晶粒主轴朝向焊缝熔合线方向,稀释率变低。