F. Chai
,
C.F. Yang
,
H. Su
,
Y.Q. Zhang
,
null
,
null
金属学报(英文版)
Effects of Zirconium on the chemical component and
size distribution of Ti-bearing inclusions, favored the grain
refinement of the welding induced, coarse-grained heat affected zone
(CGHAZ) with enhanced impact toughness in Ti-killed steels, which
were examined based on experimental observations and thermodynamic
calculations. It indicated that the chemical constituents of
inclusions gradually varied from the Ti-O oxide to the Ti-O+Zr-O
compound oxide and a single phase of the ZrO 2 oxide, as the Zr
content increased from zero to 0.0100\%. A trace of Zr
(0.0030 %--0.0080n %, depending on the oxygen content in liquid
steel) provided a large amount of nucleating core for Ti oxide
because of the larger specific density of ZrOn 2 oxide, and
produced a small size distribution of the inclusions favorable for
acicular ferrite transformation with a high nucleation rate in the
CGHAZ, and a high volume fraction of acicular ferrite was obtained
in the CGHAZ, with enhanced impact toughness. Otherwise, a high
content of Zr (~0.0100 %) produced a single phase ZrO 2,
which was impotent to nucleate acicular ferrite, and a
microstructure composed of ferrite side plate and grain boundary
ferrite developed in the CGHAZ. The experimental results were
confirmed by thermodynamic calculations.
关键词:
Nonmetallic inclusions
,
null
,
null
