| With the development of A-TIG technology,the problem is even remarkable for the back shielding of weld.The common methods are argon atmosphere,ceramic backing,mixed gas and so on,but these measures have theirs limitation.The back shielding fluxes are developed for A-TIG welding of stainless steels and low carbon steel.The back shielding fluxes of stainless steels consist of Al2O3,MgO,TiO2,CaO and so on.The back shielding fluxes of low carbon steel consist of Al2O3,TiO2,SiO2,NaCl and so on.The influence of various mono-components shielding fluxes on oxidation resistance are analyzed by means of mark.The components of shielding flux are confirmed according to the alloy system of stainless steels.A formula is obtained by orthogonal test,range analysis and variance analysis.The formula can protect the back of the welding seam to be oxidized.Main Factors influence of protective effect are welding current,welding speed,smearing thickness and mass ratio.Protective functions are physical protection and chemical protection.Technological properties of weld form four conditions are analysised and compared.The results are that the weld of no shielding cannot meet the operating requirement and in contrary,other shielding methods can meet the operating requirement.A good weld formation is got under the protection of argon atmosphere,but the maneuverability under an argon atmosphere is not strong.A non-oxidation and good weld formation is got under the protection of "solar" shielding fluxes,but a layer of shielding membrane is formed.Subsequent wordload will be increased when the layer of shielding membrane is cleared up.The price of "solar" shielding fluxes is high. Operation is simple by self-made shielding fluxes,it can provide a new method of shielding weld. |
PDF Full Text Request