铁科院ZTK-Ⅰ型60kg·m^(-1)钢轨铝热焊接材料的研制

Development of CARS ZTK-Ⅰ 60kg·m^(-1) RailAlumino-Thermit Welding Consumables

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。

CARS ZTK- I 60 kg · m^-1 alumino-thermic welding consumables are developed according to the theory of rail thermic-welding. Chemical elements of welding metal mainly are C, Si, Mn, and other microelements are used to adjust the performance the welding metal, like intensity, hardness, tenacity, etc. The pouring temperature of the thermit metal could be appropriate if the weight of aluminium powder and the ferric oxide is 79.3 % of the total weight of the welding powder. The speed of thermit welding reaction is the fastest when the grain size of aluminium powder is 40-80 mesh and the grain size of ferric oxide powder is 30-60 mesh, at the same time the thermit powder is not easily sliced. And thermit reaction relief additive is used to reduce splash of the molten steel during the reaction. The sand mould structure is optimized by means of computer simulation of thermic steel flow field and solidification field in the pouring system. One-shot crucible is improved by stable raw material and improved thimble setting up structure. The static bending, fracture, fatigue, hardness, tensile and microstructure of the ioint are inspected, and the results accord with the standard. The performance of welding joints is excellent after long time on site application. The welding consumables are applied both home and abroad.