The Paton Welding Journal, 2015, №11



2015 №11 (09)

DOI of Article 10.15407/tpwj2015.11.01

2015 №11 (02)

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The Paton Welding Journal, 2015, #11, 10-16 pages
 

Structure and properties of weld metal modified by nanooxides

V.D. Kuznetsov And D.V. Stepanov

NTTU «Kiev Polytechnic Institute» 37 Pobeda Ave., 03056, Kiev, Ukraine. E-mail: v.kuznetsov@kpi.ua
 
 
Abstract
Given are the results of investigation of structure and properties of weld metals at introduction of nanooxide powders into weld pool. It is shown that portion of nanooxides, being introduced in the weld pool, should not exceed 0.5 % in a range of recommended modes of welding of low-alloy steels. It is determined that nanooxides introduction results in formation of mainly non-metallic inclusions in nanosize range of 0.07-0.13mm as well as in 0.3-0.8 mm range. At that increased content of carbon, titanium, oxygen, aluminum and manganese are observed in them in comparison to reference welds. It is shown that introduction of 0.5% titanium nanooxide reduces content of brittle constituents of the structure and content of acicular ferrite rises to 40 %, that results in 2 times increase of impact toughness together with simultaneous increase of yield strength. It is shown that modifying of weld metal by titanium and aluminum nanooxides reduces solidification interval, that can indicate their effect as 2nd type inoculants. 15 Ref., 3 Tables, 6 Figures.
 
Keywords: weld, low-alloy steel, nanopowder, nanooxides, structure, non-metallic inclusions, mechanical properties, solidification interval
 
 
Received:                21.10.15
Published:               21.12.15
 
 
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