| Stainless steel plays an important role in the economic construction because of its corrosion resistance,bright and clean appearance and elegant shape.It is widely used in automobile,bridge,aerospace and household appliances industry.However,during the welding process of stainless steel welding materials,the stainless steel welding fume produced by stainless steel welding materials contains elements such as Mn,Cr and so on,which contain metal elements that can cause damage to the human body.Therefore,in this paper,welding fume produced in welding process of four grades of ER308L,ER309L,ER316L and ER347L stainless steel flux cored wires widely used in production are systematically studied.This is not only conforms to the requirements of environmental sustainable development strategy,but also provides strong theoretical basis for minimizing the harm of welding fume to welding operators and taking corresponding labor protection measures in industrial production.In this paper,a welding fume pick device designed and made independently,the device is simple and convenient to collect welding fume.It meets the requirements of qualitative analysis of stainless steel welding fume in laboratory.The welding fume samples were prepared for SEM experiments.It was found that:the morphology of“primary particles”generally showed regular sphericity,and the appearance was smooth and even.Two or a few of these particles will be swallowed during the cooling process to form large particles with a global shape and spherical shape.The“Secondary particles”have the characteristics of chain structure,grape and reticulation structure,or loose porous floc.Statistic particle size and analysis the particle size distribution of the stainless steel welding fume draw conclusions that“primary particles”were divided into two different size scale of 10nm and 10~2nm,the average particle size of ER309L stainless steel flux cored wire during welding process is minimum and has also appeared in the order of 10~0nm welding fume particle;the distribution of the frequency of the particle size of the welding fume displays the distribution of two-peak profiles,and the distribution of each order of magnitude approximate the normal distribution.Through spectroscopic acquisition and calibration experiments,it is concluded that in addition to O elements,stainless steel welding fumes contain metal elements of Fe,Cr,Cu,Mn,Na,K and non-metal elements of S,Si,F.Some elements only appear in welding fumes generated during welding process of a certain flux cored wire,indicating that different grades of stainless steel flux cored wire will have different effects on welding quality due to different welding process,so different materials can be added to improve welding quality.The contents of several elements of Fe,Cr and Mn are relatively high in welding fume,and the content of Fe element is the highest.Through the analyzing of the formation mechanism of different size scale stainless steel welding fume conclude that,10~0nm size scale welding fume was formed after solidification without growing up or oxidized,that is,solidification occurs,and agglomeration is formed into welding fume,and deduce that the group is divided into a single element,and during the EDS experiment,the percentage of atoms of Fe elements in the welding fume of stainless steel in the order of 10~2nm is lower than some added elements,this is can be explained by the heterogeneous nucleation mechanism. |
PDF Full Text Request