国内外23CrNi3Mo钎具钢洁净度的差异

通过国内外23CrNi3Mo钎具钢的洁净度对比，找出在冶金环节上与国外钎具钢的差距，并对国外钎具钢中夹杂物的生成机理进行了理论热力学计算。结果表明，国外钎具钢的洁净度较高，易偏析元素砷、磷等含量远低于国内钎具钢；夹杂物的类型主要以单独的Mg Al O类夹杂物和Mg Al O外包裹MnS类夹杂物为主，夹杂物的尺寸主要为0～3 μm；纵截面上MnS夹杂物具有很明显的拉长现象，且具有很好的熔断效果，宽度为1 μm左右，纵横比为3～6。国内钎具钢中夹杂物主要为单独的Mg Al O类夹杂物和Mg Al O外包裹(Ca,Mn)S类夹杂物，尺寸以3～6 μm为主；纵截面上，单独的(Ca,Mn)S沿轧制方向几乎不变形。热力学计算表明，MnS类夹杂物的两次析出是导致Mg Al O类夹杂物的包裹率达到70%、复合类夹杂物尺寸较小的主要原因。

Comparing cleanliness of 23CrNi3Mo hollow drill steel at home and abroad

By comparing the cleanliness of 23CrNi3Mo drill steels at home and abroad, it was found that there are some gaps in metallurgy quality of the domestic and overseas drill steels. And the theoretical thermodynamics calculations of the formation mechanism of inclusions in abroad drill steels were carried out. The experiment results indicated that the abroad drill steel has better cleanliness and the lower content of the easy segregation elements such as As and P, and the simple Mg Al O inclusion and complex inclusion, for which the Mg Al O inclusion acted as the nucleation core of pure MnS, were the main types of inclusion with the main size of 0 3 μm. And on the longitudinal section, there were many elongated MnS inclusions with obvious fusing phenomenon and the aspect ratio was in the range of 3 6. The main inclusions in domestic drill steel were simple Mg Al O inclusions and complex Mg Al O＋(Ca,Mn)S inclusions, whose main size was in the range of 3 6 μm, and the (Ca,Mn)S almost did not deform in the direction of rolling. Thermodynamic calculations showed that the two precipitations of MnS inclusions were the main reasons for the encapsulation rate of Mg Al O inclusions of 70% and the smaller size of complex inclusions.