新型等离子弧粉末堆焊机理

Mechanism of New Plasma Powder Surfacing for High Efficiency and High Quality

关键词:  等离子弧焰流特性  等离子堆焊  熔敷速度  稀释率

Key words:  plasma arc flame charcteristics  plasma surfacing  deposition rate  ratio of dilution

摘要:

人们衡量堆焊方法一般总是从两个方面进行,一是熔敷速度,二是稀释率。在追求大熔敷速度的同时总是希望将稀释率控制得尽量小。目前,国内堆焊方法大都处于高熔敷速度高稀释率或低稀释率低熔敷速度的状态。熔敷速度的提高和稀释率的降低是矛盾的两个方面,二者相互制约。能否协调熔敷速度与稀释率之间的矛盾关系,是能否实现高效、高质的堆焊工艺的关键。等离子弧作为粉末堆焊的热源,其焰流特性参数是影响堆焊质量和效率的主要因素。本文从理论上定性分析了等离子弧的焰流特性参数和粉末在电弧中获得的动量和热能情况,阐述了实现高效、低稀释率等离子堆焊的机理,并据此提出了新型焊枪结构的设计原则,为进一步研制高效、低稀释率等离子堆焊系统奠定了理论及试验基础。

Abstract:

It is presented preliminary assessment of new plasma technology with both high deposition rate and low rate of dilution,which was developed under the calculation and analysis of compressive properties of plasma are, arc flame characteristics and kinematics behavior of poweder in the arc.Compared with normal plasma surfacing method,the idea using constricting nozzle with small orifice diameter, long plasma arc and increasing the distance from meeting point of two beams of powder to workpiece,to achieve the goals of high depoition rate and low rate of dilution, was put forward here first time.In order to prove this idea,a simple set of experimental system was built up and satisfied results including high deposition rate(more than 15 kg/h) and low rate of dilution (less than 1~5%) were obtained.The success of this study offer a promising prospect for developing the powder plasma hardfacing technology in China and may open a way to improve this technology further in efficiency and quality.