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根据钢轨铝热焊接原理,研制铁科院ZTK-Ⅰ型60 kg.m-1钢轨铝热焊接材料。焊剂的化学成分以碳、硅、锰元素为主要元素,用其他微量元素调节焊缝金属的强度、硬度、韧性等综合性能;焊剂中铝粉和氧化铁两者的重量占整个焊剂重量的79.3%,能够很好地控制钢水的浇注温度;铝粉粒度为40~80目、氧化铁粉的粒度为30~60目时,铝热反应的速度最快,并在运送过程中不发生分层;添加铝热反应缓释物,减少反应过程中的钢水飞溅。通过数值模拟方法分别模拟铝热钢水在浇注系统中的流场和凝固场,改进浇注系统,优化砂型结构。一次性坩埚内胎由不参于铝热反应的耐火材料制成,并采用阶梯式的自熔塞埋制结构。依据有关标准,对焊接接头的静弯、断口、疲劳、硬度、拉伸和金相组织进行检测,检测结果均符合相关技术条件。现场应用情况表明,焊接接头服役状态良好。此焊接材料已经在国内外推广应用。
According to the principle of rail aluminum heat welding, research ZTK-Ⅰ type 60 kg.m-1 rail aluminum heat welding materials. Flux chemical composition of carbon, silicon, manganese as the main element, with other trace elements to adjust the weld metal strength, hardness, toughness and other comprehensive performance; flux of aluminum and iron oxide weight of both the weight of the entire flux of 79.3 %, Can well control the pouring temperature of molten steel; aluminum powder particle size of 40 to 80 mesh, iron oxide particle size of 30 to 60 mesh, the fastest thermal reaction aluminum, and in the transport process does not occur stratification ; Add aluminum reaction heat-release material to reduce the molten steel during the reaction spatter. The numerical simulation method was used to simulate the flow field and the solidification field of the hot metal in the casting system respectively, to improve the casting system and optimize the sand structure. The disposable crucible tube is made of a refractory material that does not participate in the aluminothermic reaction and is embedded in a stepped self-fusing plug. According to the relevant standards, the static bending, fracture, fatigue, hardness, tensile and microstructure of the welded joints were tested, the test results are in line with the relevant technical conditions. Field application shows that the welded joints in good service. This welding material has been popularized at home and abroad.