ABSTRACT

The influence of addition sequence of Mg, La and Ca on the characteristics of inclusions and the formation of acicular ferrite (AF) were investigated. Results show that inclusions mainly consisted of La–Ca–Mg–Al–Ti–O+MnS in the steel. There was no change to types of inclusions while the layered structure of inclusions was different under different alloy elements addition sequence. The number density of inclusions was the largest in case of Mg was added first, while the average size of inclusions was the smallest. The main type of effective inclusions (nucleus of AF formation) was oxide with MnS shell. The statistical results indicated that the proportion of effective inclusions in case of Mg addition first was the largest among the three samples, which induced more AF formation.

摘要

研究了Mg、La和Ca的添加顺序对夹杂物特征和针状铁素体(AF)形成的影响。结果表明，钢中夹杂物主要由La-Ca-Mg-Al-Ti-O+MnS组成。不同合金元素添加顺序下夹杂物的种类没有变化，但夹杂物的层状结构不同。夹杂物的个数密度在先加入Mg的情况下最大，而夹杂物的平​​均尺寸最小。有效夹杂物（AF 形成的核心）的主要类型是具有 MnS 壳的氧化物。统计结果表明，在三个样品中，先添加镁的有效夹杂物比例最大，导致更多的AF形成。