摘要
一般钢中加Ti可使晶粒细化,从而提高钢的强韧性。但D6AC超高强度铟中可否加Ti的问题,一直存在争论。因为加Ti后,可能生成含Ti夹杂物而使韧性降低。为了改善D6AC钢的韧性,首先需要弄清这一问题。本文系统研究了含Ti夹杂物对D6AC钢强韧性的影响,并与同一钢种中,含有常见的MnS夹杂物进行比较,得出: 1.TiS夹杂物对强度和延伸率的影响不明显; 2.TiS夹杂物对面缩率、冲击韧性和断裂韧性稍有影响; 3.TiS开裂％随应变增大而增加,但在同一应变下却低于MnS; 4.TiS夹杂物使K_(1C)值降低的幅度低于MnS,因此,D6AC钢中加Ti可以改善强韧性。
In order to improve the toughness of D6AC steel someone suggested that titanium fine grains be added to it. But inclusions might form and cause the toughness to decrease. There fore, it is necessary to study systematically the effects of inclusions on the properties of D6AC steel by comparing D6AC steel containing inuclsions with D6AC steel added to titanium. Therefore, it is necessary to study systematically the effect of these inclusions on properties and compare the inclusion in D6AC steel with D6AC steel added titanium. The main conclusions to be drawn from this paper are: 1. The effect of TiS inclusion on strength, hardness and elongation of D6AC steel were not obvious. 2. There was certain influence of TiS on area reduction(φ), V-notch impact energy (CVN) and fracture toughness (K_(1c)). 3. The nucleation of micro-crack on TiS inclusion formed mainly by cracking the inclusion itself. Critical strain of cracked TiS inclusion was inversely proportional to the size of the inclusion. 4. Percentage of cracked TiS increased with increasing strain, and the percentage of cracked TiS was lower than that of MnS under the same strain. 5. Fracture toughness of D6AC steel will be decreased 33.8% for MnS but only 5% for TiS under the same structure, grain size and approximate inclusion content.
基金
国宗自然科学基金资助项目
关键词
钢
夹杂物
断裂韧性
TI
超高强度钢
duble vacuum metallurgy
inclusion
fracture toughness
crack nucleation
rate of nucleation
