多元硅锰焊剂的试制

本文对所研制的多元硅锰渣系焊剂——“试771”焊剂进行了论述。该焊剂是根据我国锰矿特点,以矿源丰富、成分比较稳定的锰矿为选材而研制的,它的渣系以SiO_2、MnO为主并含有一定量的CaO、Al_2O_3,它具有良好的抗气孔和抗裂纹性能,适用于低碳钢及低合金钢的焊接。     

适于1Cr13NiMoVNb型带极高速堆焊用烧结焊剂的研制

按实际生产的要求,研制一种适合于1Cr13NiMoVNb型带极高速堆焊用的烧结焊剂。经过多次实验,利用正交实验法对数据进行分析,得出了烧结焊剂在要求的焊接工艺规范下各个成分的最佳配合比,用此种焊剂堆焊后焊道的脱渣性好、焊道表面平整光滑,堆焊层中各主要组成元素的百分含量满足要求。最后,对烧结焊剂在焊接过程中的电弧稳定性,焊后的脱渣难易程度、焊道成型情况以及焊道表面的抗氧化性等焊接工艺性进行综合分析,给出了各个组分对焊接综合工艺性的影响趋势。     

500qE桥梁钢埋弧焊剂研究

考虑500q E桥梁钢焊接接头对低温冲击韧性、抗裂纹和焊缝中低扩散氢含量有较高要求,选择CaO-CaF_2-MgO-Al_2O_3-SiO_2渣系进行埋弧烧结焊剂设计,采用均匀设计法得到了优化的焊剂。采用优化的焊剂配合TGM-H65Q焊丝进行埋弧自动焊接试验,研究了焊接接头的力学性能及微观组织。结果表明,使用X105-3焊剂得到的焊缝成型美观,焊道光滑平整、无粘渣和咬边,脱渣性好;熔敷金属组织由块状先共析铁素体、针状铁素体和粒状贝氏体组成,熔敷金属力学性能达到母材的性能要求。使用X105-3焊剂进行埋弧自动焊得到的接头综合性能最佳,焊缝中分布着大量的细晶铁素体。     

奥氏体不锈钢高速带极电渣堆焊用烧结焊剂CHF25B的研制

国外高速带极电渣堆焊速度已达40 cm/min以上且焊接工艺性能良好,而国内配套的高速带极电渣堆焊焊剂在高速焊接时容易出现咬边、焊道成形差、产品质量不稳定等缺陷,这类焊材主要依靠进口,在一定程度上制约着我国制造业的发展.研制了一种奥氏体不锈钢带极电渣堆焊用烧结焊剂CHF25B,渣系为CaF2-Al2O3-SiO2,碱度...     

TiO_2-FeO-(SiO_2,CaO,MgO)三元渣系的流变特性

利用内圆柱体旋转法测试TiO_2-FeO-SiO_2、TiO_2-FeO-CaO和TiO_2-FeO-MgO三元高钛渣体系的黏度和熔化性温度的变化规律,并结合XRD及激光拉曼光谱对高钛渣结构进行初步的表征。结果表明:SiO_2含量增加会提高三元钛渣黏度及熔化性温度,恶化熔渣流动性。CaO和MgO含量增加会降低钛渣黏度及熔化性温度,改善熔渣流动性;钛渣完全熔化后,黏度约为70~100 m Pa·s,继续升高温度对钛渣黏度无显著影响。经XRD和Raman光谱分析可知:钛渣凝固后TiO_2以金红石形式存在。SiO_2、MgO和CaO的添加对TiO_2-FeO二元钛渣拉曼特征峰影响不大,但均能使特征峰发生红移;Ca~(2+)和Mg~(2+)以网格修饰子形式进入钛氧八面体,形成CaTiO_3和MgTi_2O_5。     

TiO_2-CaO-SiO_2渣系磁性焊剂的研究

磁性焊剂 CO_2明弧半自动焊是一种先进的焊接方法。但直到目前为止,国内外对磁性焊剂渣系及焊接工艺的系统资料还很少。在这种情况,我们本着多快好省及土洋结合的原则进行了实验研究,并取得了一些结果,尤其对于 TiO_2-CaO-SiO_2渣系的磁性焊剂方面的研究。本研究工作由天津大学焊接专业、天津船舶修造厂、新港船厂及新河船厂四个单位协作共同进行的。     

焊剂碱度对核电站预埋件埋弧螺柱焊焊接性能的影响

分别采用酸性焊剂HJ431、碱性焊剂SJ101和中性焊剂SJ301对核电站锚固钢筋式预埋件进行埋弧螺柱焊焊接试验。对焊缝进行外观检测以及宏观金相、显微组织、硬度、力学性能等检测,并采用扫描电镜对焊接缺陷进行观察和分析。结果表明,使用酸性焊剂HJ431进行焊接所得焊缝易夹渣,导致焊接接头拉伸性能不合格率高达37.5%,其原因可能是焊接时熔渣黏度过大、流动性不好造成的;采用碱性焊剂SJ101进行焊接易发生磁偏吹,这与焊接时电弧周围磁场分布不均匀有关;采用中性焊剂SJ301进行焊接,脱渣性能较好且电弧挺直度高,焊接接头无夹渣和磁偏吹现象,各项力学性能均满足标准要求。     

新型2205型双相不锈钢埋弧焊用烧结焊剂

开发了焊接2205型双相钢的埋弧焊用烧结焊剂,渣系为CaF2-SiO2-MgO-Al2O3,属于中性焊剂。该焊剂有良好的工艺性能和冶金性能,配合焊丝ER2209焊接所得熔敷金属为铁素体+奥氏体双相结构。熔敷金属有较高的强度和良好的塑性,其中铁素体含量为22%～35%。研究发现室温时效时间和焊道最终温度对熔敷金属中的铁素体含量有影响,随着室温时效的延长和焊缝最终温度的降低,熔敷金属中的铁素体含量增加。     

镍基电渣堆焊高速焊焊剂JWF631DZ的研制

研制了一种625型镍基电渣高速堆焊焊剂。该镍基焊剂焊接时焊接速度可达250 mm/min,此焊速下焊道的搭道处表面平整、光洁,无咬边。本文对该焊剂匹配EQNiCrMo-3焊带的焊缝金属做了较为全面的工艺及性能试验,其焊缝金属的化学成分、弯曲性能、晶间腐蚀和氯化物应力腐蚀试验均达到用户的相关技术标准要求。     

NaOH碱熔分解CaSiO_3过程中导致硅酸盐结构转变的反应路径（英文）

以NaSiO_3·9H_2O和CaCl_2为原料,通过化学沉积法合成链状硅酸盐(CaSiO_3)。采用拉曼光谱、X射线衍射和红外光谱研究其在NaOH碱熔过程中的分解机制。结果表明,CaSiO_3在碱熔过程中链状结构的硅氧四面体结构逐渐断裂、转变生成岛状结构的硅氧四面体。CaSiO_3分解过程中同时生成3种中间体:Ca_2SiO_4,Na_2CaSiO_4和Na_2SiO_3,最终产物是Ca(OH)_2和Na_4SiO_4。因此,CaSiO_3在NaOH碱熔融反应过程中存在两条反应途径,分别以离子交换和硅酸盐骨架结构改变为主要形式,碱熔过程中硅酸盐结构的变化贯穿于整个反应过程。     

焊剂组元间交互作用对熔化温度的影响

利用数理统计理论发展起来的混料优化设计方法,建立数学模型,研究了焊剂组成成分间交互作用对熔化温度的影响问题,揭示了埋弧焊陶质焊剂7组元间交互作用,对焊剂熔化温度的影响规律,得到了焊剂组成成分对熔化温度影响的定量描述回归方程.结果表明,MgO-TiO2-CaCO3-Al2O3的交互作用,能在熔渣中形成相当数量的钙钛矿和尖晶石,使焊剂的熔化温度提高,而一定数量的CaF2和SiO2、ZrO2的加入则可使焊剂的熔化温度降低.     

药芯焊丝焊接材料的发展

阐述了药芯焊丝气体保护焊及焊接材料制造慨况,以及药芯焊丝气体保护焊的特点,如适应性好、易掺合金、熔敷率高、熔深大、工艺性好、力学性能好、生产率高、节能节材等;研究证明,药芯焊丝和自保护药芯焊丝的焊接接头性能好、生产率高.随后介绍了国外及国内应用现状及发展,对我国工程应用实例及试验研究成果近行了分析.     

无腐蚀、不溶性钎剂的新进展

综合了铝及其合金钎焊的研究发展概况，介绍了近年来无腐蚀，不溶性钎剂（Nocolok)方法应用于铝钎焊的工艺，Nocolok钎剂由KF－AlF，系中的两上中间化合物NAlF4-K3AlF6间的共晶点组成，其主要作用为去除铝表面的氧化膜，使铝件钎焊且焊缝美观。但由于钎剂的成分要求准确，否则熔点偏高，限制了钎焊铝合金的工艺的应用，因此国内外近年对Nocolok方法进行了改进探讨，并对Nocolok的发展动态进行了研究，Nocolok方法具有很大潜力，但其作用机理还有待更深入探讨。     

Variation of the stress dependent magnetic flux leakage signal with defect depth and flux density

The effects of uniaxial stress on the normal (radial) component of the magnetic flux leakage (MFL) signal induced by blind-hole defects for depths of 25%, 50% and 75% of the thickness of the pipe wall were investigated with a pipe wall flux density of 1.24 T. These three defects were on the same surface as the magnetizer and sensor for the MFL signal (near side). A fourth 50% defect was on the pipe wall surface opposite the sensor (far side). Changes of as much as 47% in the MFL signal due to stresses of up to 300 MPa were observed. Increased changes in the stress dependent MFL signal were observed with increasing defect depth. Comparison of the near side and far side 50% defects indicated similar changes in the MFL_pp signal as a function of stress, although the shape of the MFL signals was qualitatively different. The stress dependent MFL signal was also investigated for the near side 50% defect for pipe wall flux densities between 0.65 T and 1.24 T. A linear increase in the effects of stress on the MFL signal with increasing flux density was observed. Results demonstrated that the variation of the MFL signal with stress is primarily a bulk stress effect, although the effect of defect-induced stress concentrations upon the various MFL signals investigated could also be observed.     

烧结粘结复合合金焊剂的研制

石油工业发展大幅度需求大口径热轧无缝钢管,热轧无缝钢管所用芯棒大多依赖进口,且轧制时易于因热疲劳裂纹及表面擦伤而报废,为降低成本迫切需要探求一种修复报废芯棒的方法。针对细长芯棒堆焊修复的需要,开发了一种新型气孔倾向低的烧结粘结复合合金堆焊焊剂。该焊剂能向熔池中过渡Mo、V、Nb等合金元素及Y、Ce等稀土变质剂元素,经过试验证明,该焊剂细化了堆焊层晶粒,满足了堆焊层金属的力学性能要求,并且成分较低,抗气孔能力强。经过6年的堆焊芯棒生产实际考验,证明所堆焊的芯棒基本恢复使用性能,可以证明该焊剂的研制是成功的。     

焊剂带在其约束电弧中的位置与其电位相关性分析

焊剂带遮电弧中的位置是约束电弧的关键,并决定着电弧的加热特性.为了能够更好地将焊剂带约束的电弧应用于超窄间隙焊接,通过采集相当于电弧探极的焊剂带上的电压波形,对焊剂带在电弧中的位置进行了分析.结果表明,通过采集焊剂带电压波形并根据电压波形值的大小,可判断出焊剂带在电弧区的位置及熔化的焊剂带向熔池中过渡的方式.增加焊剂带距电弧中心距离,会使焊剂带在电弧区的位置发生改变,同时还减小了弧柱对焊剂带的加热效果及熔滴与焊剂带接触的频率.此外,测得了电弧区不同焊剂带电位所对应的焊剂带位置.     

Laser welding with activating flux

Abstract

The effect on laser welding of activating flux, originally developed to improve penetration depth for tungsten inert gas welding, was investigated. Both mild and stainless steels were tested. Results show that weld penetration capability relates closely to the laser power level and welding speed of the process. Significant improvement in penetration was only observed when laser welding was performed in the conduction mode (i.e. weld aspect ratio <1). For the range of parameters studied, the best penetration capability improvements achievable for mild steel, type 304 stainless steel, and duplex stainless steel were found to be 41, 53, and 63% respectively. These data are of use in the selection of parameters for laser welding with activating flux.     

Welding of titanium alloys with activating flux

Abstract

In the present paper, the effects of an activating flux on Ti–6Al–4V alloy welding were investigated. Tungsten inert gas welding was used to weld 8.0 mm thickness Ti–6Al–4V alloy plates. Results show that applying the activating flux on the Ti–6Al–4V alloy surface leads to an increase in weld penetration depth, whereas the corresponding weld bead width is reduced. It was also found that various welding conditions, particularly flux thickness, influence the effectiveness of the activating flux. Furthermore, a data acquisition system was used to monitor the current and voltage signals during welding. Results from monitoring of the welding current and voltage signals reveal that there is a clear correlation between the signals and the weld penetration when the welding arc is steady. Analysis of the acquired signals can be used to identify inconsistencies in weld penetration. In summary, to take advantage of the use of activating flux in Ti alloy welding, it is important that a uniform flux layer is present at the alloy plate surface and suitable welding parameters are selected.     

Welding of magnesium alloys with activating flux

Abstract

The effects of an activating flux on AZ31B alloy welding were investigated. Alternating current tungsten inert gas (ACTIG) welding was used to weld 5·0 mm thick AZ31B alloy plates with CdCl₂, AlF₃ and TiO₂ activating flux. Applying the activating flux on the AZ31B alloy surface led to an increase in weld penetration depth. Various welding conditions, such as welding current, welding arc length, welding shielding gas flowrate, welding speed and flux thickness, influenced to different extents the ability of the activating flux to increase weld penetration. Furthermore, a high speed camera was used to monitor the arc images during welding. It was found that the brightest region of the arc was broader when CdCl₂ and AlF₃ were used, while the stability of the arc was increased when TiO₂ was used, especially in the positive electrode period. In summary, it is important that a uniform flux layer is present at the alloy plate surface and suitable welding parameters are selected.