SI Zhongyao WANG Zhaoqing LIU Peng YU Dehua LIU Lei ** Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China*** Capital Iron and Steel Company
,
Beijing
,
100053
,
China+ To whom correspondence should be addressed
材料科学技术（英）
Effects of microalloying Ti and B on the microstructures and low temperature toughness of manual metal arc (MMA) deposits were investi- gated.Weld metals containing 200-300 ppm Ti and 29-60 ppm B deposited by manual coated elec- trodes provided an optimum low temperature toughness.The addition of B in weld metals low- ered the γ→α transformation temperature which promoted the acicular ferrite (AF) transformation. Solid solutioned B suppressed grain boundary ferrite as well as side plate ferrite formation and benefited the acicular ferrite formation.Titanium protected B from oxidizing as well as nitriding and formed Ti-Mn silicate inclusions.Ultra-high volt- age electron microscope analyses showed that TiO structure in the Ti-Mn silicate inclusions was the favorable nucleation site for acicular ferrite forma- tion.
关键词:
toughness
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