【作者】 马志宝；

【导师】 李午申；

【作者基本信息】 天津大学 ， 材料加工工程， 2009， 硕士

【摘要】 随着国民经济的发展和对石油、天然气资源需求的急剧增加,管线建设如火如荼。以适合野外施工,抗风能力强的自保护药芯焊丝得到了广泛的应用。但是,我国管道焊接用的全位置自保护药芯焊丝主要依靠进口美国林肯公司和哈伯特公司的产品,国内迫切需要提高自保护药芯焊丝的质量。药粉预处理对焊丝的工艺性能具有很大的影响。本文首次提出用水代替钾钠水玻璃作为药粉粘结剂,效果很好,既节约了粘结剂的费用,又可以充分利用筛分掉的细粉,具有很大的经济效益。同时确立烧结温度在700⁸50°之间,保温半小时。经过预处理,不但提高了药粉的均匀性、耐潮性、流动性,而且还除去了药粉中有害化学成分,改善了焊丝的工艺性能。熔滴过渡形式影响药芯焊丝的工艺性能和力学性能,本文借助高速摄影设备对研制的X80管线钢用自保护药芯焊丝的熔滴过渡形态及冶金因素对熔滴过渡的影响进行了研究。发现电弧燃烧过程中不存在滞熔性渣,药芯的熔化先于钢带,熔滴过渡以附渣过渡和爆炸过渡为主。渣系中Fe₂O₃、Li₂CO₃、Al-Mg等对熔滴过渡行为有较大的影响,本文设计三组试验,对采集的焊接电弧的电压电流信号进行统计分析,总结出其对熔滴过渡及焊接工艺的影响规律。Fe₂O₃降低熔滴的表面张力,细化熔滴,但提高药粉的熔点,增大飞溅。Li₂CO₃的影响比较复杂,含量较少时,细化熔滴作用不明显,含量多时,增大飞溅。Al-Mg增加电弧温度,降低熔滴表面张力,细化熔滴,但焊接时增大烟雾。综合考虑,Fe₂O₃含量为10,Li₂CO₃含量为2,Al-Mg含量为14时,整体效果较好。成功研制了BaF₂- Al-Mg渣系的自保护药芯焊丝,按照西气东输二线管道工程线路焊接技术规范,对焊丝的工艺性能和接头的力学性能进行了综合评定,评定结果良好。更多还原

【Abstract】 Pipeline construction has been increased with the nation economy development and increased dramatically demand of oil and natural gas. The Self-Shielded Flux Cored Wire（ SSFCW） as is suitable for construction field and strong wind resistance is widely used for all-position welding of pipeline,but the majority of consumed SSFCW in China relies on importing the product of Lincoln and Hobart corporation due to the poor quality of domestic SSFCW. So there is an urgent need to develop the domestic SSFCW.Pre-treatment process of the powder has a great impact on performance of the wire. In this paper, the water was first proposed as a powder binder, which is more effective than sodium silicate binder. It not only saves the cost of the binder but also can take full advantage of the fine powder screened out , so it has great economic benefits. At the same time, the sintering temperature of the powder is established between 700⁸50°,and the holding time is half an hour. It improve the uniformity of powder, powder flow, reduce water absorption, remove the harmful chemical components in the power and improve the performance of wire.Metal transfer can affect process and mechanical properties of SSFCW. In this paper, metal transfer patterns of SSFCW were studied by high-speed photographic equipment, and the impact of metallurgical factors on metal transfer was also studied. The result is that there is no hysteresis slag in arc combustion, the flux melts before strip, the main forms of the metal transfer are explosive transition and slag attached transition.Fe₂O₃, Li₂CO₃, Al-Mg in slag have a great impact on metal transfer. Through three sets of tests, the signals of welding voltage and current were statistically analyzed, summarized their impact on droplet transfer and welding technology, Fe₂O₃ in the flux can reduce the surface tension of metal droplet, make droplet refined, but it increase the melting point of powder and spatter. The impact of Li₂CO₃ in the flux on metal transfer is more complicated than Fe₂O₃. When the content of Li₂CO₃ in the flux is less, the effect on droplet refinement is not obvious, but when it is more, the spatter is increased. Al-Mg in the flux can increase arc temperature, lower the surface tension of droplet, but it increase welding fumes. At last the conclusion is considered : when the content of Fe₂O₃ is 10, the content of Li₂CO₃ is 2, the content of Al-Mg is 14, the overall effect is good.The self-shielded flux-cored wire in slag system of BaF₂-Fe₂O₃-Li₂CO₃-Al-Mg was successfully developed. In accordance with the specification of second West-East Gas Transmission Pipeline Project, the performance and mechanical properties of the wire was comprehensively assessed, the results is good.更多还原