10455

9650

كارشناسي ارشد

شناسايي و انتخاب و روش ساخت مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي مواد

1394

سيزده، 77ص.: مصور، جدول، نمودار

علي شفيعي

علي اشرفي

1394/07/04

رحمت الله عمادي، عبدالمجيد اسلامي

1396/10/04

كتابنامه

مواد

مهندسي مواد

ID9650

به فارسي و انگليسي

78 Simultaneous synthesis and cladding of molybdenum on 304 stainless steel using GTAW process Seyed Farzad Alizadeh Farzad alizadeh@ma iut ac ir 2015 07 06 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor ali shafyei Associate Professor shafyei@cc iut ac irAbstractOne of the most popular processes in surface engineering is coating the surface of thespecimens since the surface of the industrial specimen is the most important part of them many destruction mechanisms are usually begins from their surface Therefore claddingcan be defined as a low cost method for coating by filler metal on a work piece in order toimprove hardness and microstructure for this purpose in this study cladding of304stainless steel and molybdenum synthesis from molybdenum trioxide and its effects onthe microstructure and hardness of the resulting clad with and without the presence of acidboric and carbon is studies simultaneously Due to this end 304stainless steel samples arecladded by GTAW process with a constant current and speed of welding At first thepowder mixture including MoO3 H3BO3 and C mixed in a ball mill with a specified moleratio Then pre placed paste cladded on the base metal Then placed in an oven with thetemperature of 80 c for an hour finally the samples welded Result shows that byincreasing boric acid because of its exothermic the temperature of weld pool increasesand more molybdenum synthesis is formed from molybdenum trioxide which causes inincreasing the ratio of Cr Ni eq By increasing this ratio the structure would be as lathyferritic While by adding carbon the ratio decreased and microstructure of clad change tovermicular ferrite To identify the formed phases in clad surface XRD has been used Based upon XRD of cladded samples existence of MoC FeMo MoNi4 phases Show thatmolybdenum synthesis is formed in arc By using micro hardness test hardness profile of samples provided which most hardnessobtained in MoO3 C 1 5H3BO3 sample Also hardness of 190 viker in base metalincreased to almost 340 viker in the clad Furthermore using macrostructure images ofweld pool it can be concluded that by increasing the amount of ferrite in clad as a result ofits increasing thermal conductivity the ratio of depth to with of the welded clads havebeen decreased Keywords Synthesis molybdnum 304 stainless steel lathy ferritic GTAW

علي شفيعي

علي اشرفي

رحمت الله عمادي، عبدالمجيد اسلامي