煤炭伴生资源——粉煤灰在A-TIG中应用研究

Given the fact that coal ash can effectively increase penetration of TIG welding bead,exploration in mechanism and basic theories the of multi-component coal ash ,as activating flux in TIG,in improving dimension of TIG welding beam will be underlined.By using activated multi-component coal ash as flux ,as well as applying thermal-dynamics,kinetics and theories of physical chemical to controlling penetration of TIG welding beam,the components and their properties under the argon arc can be known, the diffusing procedure of elements under the effect of electro-magnetic force,gravity,and surface tension and their combination can be expounded,the evoluting regulation of surface tension of liquid metal in molten poor after adding activating flux will be investigated,the influence of coal ash ,as TIG welding activating flux ,in the welding arc shape and arc force evolution will be ascertained.Meanwhile,the mechanism of coal ash in changing morphology of welding beam will be researched,its relevant physical model will be founded,a brand-new activating flux that is efficient and environmental-friendly will be developed.This project was put forward by fully concerning the fact that China has a numerous consumption of coal but the low utilization rate of coal ash ,as well as the request of environmental conservation and sustainable development,improving the utilization of coal ash so as to improve the environment will well answer the problems that was previously proposed,furthermore,this project will help blaze a new trail on the way of developing by-products of coal resources.

针对粉煤灰能够有效增加焊缝深度的优点，重点探索多组分粉煤灰作为焊接活性剂改变焊缝金属熔池形貌过程中遇到的重大基础理论问题。应用热力学、动力学和物理化学理论，采用经活化后的多组分粉煤灰进行熔池厚度的调控，研究在电弧作用下的液态金属熔池内粉煤灰存在的组分及其物理化学性能，研究其在电磁力、重力和表面张力多场耦合条件下的扩散过程，探究液态金属在添加粉煤灰后的表面张力演化规律，分析粉煤灰对焊接电弧形态及电弧力演变的作用机理和对焊缝形貌改变的机制，建立粉煤灰焊接活性剂的物理模型，开发出高效环保的焊接活性剂，为煤炭伴生资源开发利用提供一条有效的新途径。

以固体废弃物-粉煤灰作为钨极氩弧焊的活性剂。通过所设计的电弧特性检测系统分析了粉煤灰活性剂对电弧动态电流、电压、电流密度和电弧力的影响规律；研究了不同温度、不同添加量时粉煤灰对液态金属表面张力的影响规律，并通过阻流实验阐明添加粉煤灰后的熔池流动行为；将粉煤灰活性氩弧焊应用于B-C-S及B-C-N渗层的重熔，分析了添加粉煤灰后对渗层组织及性能的影响规律；以高铝粉煤灰作为添加剂主体，在基体的表面制备具有耐磨耐蚀性能的涂层，分析了添加粉煤灰后对铁基、镍基堆焊层组织及性能的影响规律。. 电弧特性研究说明：粉煤灰的添加导致实时焊接电压升高，电弧收缩后电流密度增加，在增加的电场作用及收缩后的电弧耦合作用下导致电弧力增加，加大了电弧对焊接熔池的作用效果，使熔池表面下降继而增加焊接熔深。熔池流动行为研究表明：粉煤灰的加入降低了液态金属的表面张力，尤其是高温区表面张力，导致由于温度差异所产生的表面张力梯度减少，继而使熔池液态金属由中心向边缘流动的趋势得到抑制，在增加的电弧力的作用下，液态金属以向下的流动为主，产生了流动方向的变化。电弧特性及熔池流动行为说明粉煤灰作为碳钢类材料钨极氩弧焊活性剂的机理是：电弧收缩后电弧力增加，表面张力梯度降低，两者耦合后产生焊缝熔深增加。. 采用活性钨极氩弧焊重熔B-C-S及B-C-N渗层的研究表明：粉煤灰加入后能够增加渗层与基体的结合，促进新的金属间化合物相的生成，继而提高其耐磨性。以高铝粉煤灰为主体的表面堆焊层制备的研究说明：粉煤灰加入后能够促进耐磨物质的原位析出，提高堆焊层的耐磨性。. 实验结果表明：粉煤灰作为碳钢类材料钨极氩弧焊的活性剂并应用在相关的材料热加工领域是可行的。添加粉煤灰能够增加焊缝熔深、细化晶粒、提高接头的力学性能；促进新的金属间化合物生成、提高涂层的耐磨性。因此粉煤灰作为添加剂应用在材料热加工领域具有较好的前景。