Font Size: a A A

Study Of Self-shelded Flux-cored Wire

Posted on:2006-02-16Degree:MasterType:Thesis
Country:ChinaCandidate:Q F NiuFull Text:PDF
GTID:2121360152489080Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
Flux-cored electrodes are a new type of consumabes , which develop most rapidly and the most attractive in recent years.Based on the reseach of slag system now available,the thesis modifies CaF2 - Al2O3- CaO slag system according to Chinese condition and develops,successfully in our country for the first time,a high basic index,low hydrogen and 500Mpa class self-shelded flux-cored electrod(SSFCE).Then the systematical investigationare aimed at study of the key problems of operative performance and mechanical properties.A difficult poit of developing SSFCE is slag detachability. Slag detachability and mechanism of stick slag of basic SSFCE have been first studied, from physical properties, chemical properties and the microstructure of melting slag, by means of the test plan designed by mixing material regression. It is found that there has been a good correlative relationship between liner expassion coefficent and slag detachability.Spatter is one of the important tagets to judge operative performance of SSFCE.The experiment show: three types of spatter exist inSSFCE, which are large granular spatter, small granular spatter and spatter caused by melting pool. Spatter can be decreased by adjusting flux-cored compositions, and a better way is to add surface active agent.The main metheds to slove properity are changing formula to adjust physical and chemical properties os slag at high temprature. Welding parameters, especilly voltage and extension length, have an obvious effect on porosity.The mechanical properties are another impoetant side and their kernal is impact toughness. Controlling C, Al, Si content and adding microallloy elements Re, B in high Al alloy system are better ways to improve the impact toughness os deposited metal. After discussing the behavior of Al and non-metallic inclusion in great details,the thesis advances the mechanism of Al-B system to improve impact toughness.A satisfactory result-Akv(0℃)reaches 97J, has been obtained.Finally, valuable exploration have done about the effect of three flux pretreatments prefuse, drying at high tempreture and Sol-gel, on the quality of SSFCE.
Keywords/Search Tags:self-shielded Flux-cored Eletrode(SSFCE), CaF2-Al2O3-CaO, Slag System, Slag Detachability, The Mechanical Properties.
PDF Full Text Request
Related items