Scholarlink

<p>The effect of varied total gadolinium (T.Gd) contents on the morphology and number density of sulfides and the mechanism of improving steel machinability by spherical sulfides were studied. Under different cutting parameters, relationships between chip breaking and machinability as well as tool wear were also investigated. When the content of T.Gd in the steel increased from 0 ppm to 730 ppm, the order of sulfide transformation behavior was as follows: MnS→(Al–Gd–O)–Al<sub>2</sub>O<sub>3</sub> core wrapped with MnS layer→(Gd–O–S)–MnS layer on the Al<sub>2</sub>O<sub>3</sub> nucleation→(Gd–O–S)–(Gd–S) composite inclusion→(Gd–S)–MnS composite inclusion. The number density of sulfides increased from 570.2 #/mm<sup>2</sup> at T.Gd&#xa0;=&#xa0;0 ppm to the maximum value of 851 #/mm<sup>2</sup> at T.Gd&#xa0;=&#xa0;150 ppm and then decreased to the minimum value of 109.1 #/mm<sup>2</sup> at T.Gd&#xa0;=&#xa0;730 ppm in the steel. The proportion of sulfides inclusions with aspect ratio in the range of 1~3 increased from the minimum value of 23.4 pct at T.Gd&#xa0;=&#xa0;0 ppm to the maximum value of 99.9 pct at T.Gd&#xa0;=&#xa0;730 ppm. At the cutting speeds of 110 and 280 r/min<sup>−1</sup>, the formation of C-type chips was observed since the hole around the inclusion was expanded through the full rolling of the spherical sulfide, while long chips were found due to the hole around sulfides being hardly expanded at the high cutting speeds of 350 and 560 r/min<sup>−1</sup> as T.Gd&#xa0;=&#xa0;462 ppm and 730 ppm, which resulted in the improvement of the machinability of the steel. The wear of the tool was negatively related to hardness of the steel matrix. In the steel with 462 ppm T.Gd, the surface roughness was the lowest and the tool wear was the smallest.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Novel Method for Improvement of Machinability of a High-Sulfur Free-Cutting Steel by Adding Gadolinium

  • 期刊论文

  • 发表日期：

    2025年7月2日

查看全文
  • Xiqing Zhao,
  • Hong Wei,
  • Shengchao Duan,
  • Lifeng Zhang

摘要

The effect of varied total gadolinium (T.Gd) contents on the morphology and number density of sulfides and the mechanism of improving steel machinability by spherical sulfides were studied. Under different cutting parameters, relationships between chip breaking and machinability as well as tool wear were also investigated. When the content of T.Gd in the steel increased from 0 ppm to 730 ppm, the order of sulfide transformation behavior was as follows: MnS→(Al–Gd–O)–Al2O3 core wrapped with MnS layer→(Gd–O–S)–MnS layer on the Al2O3 nucleation→(Gd–O–S)–(Gd–S) composite inclusion→(Gd–S)–MnS composite inclusion. The number density of sulfides increased from 570.2 #/mm2 at T.Gd = 0 ppm to the maximum value of 851 #/mm2 at T.Gd = 150 ppm and then decreased to the minimum value of 109.1 #/mm2 at T.Gd = 730 ppm in the steel. The proportion of sulfides inclusions with aspect ratio in the range of 1~3 increased from the minimum value of 23.4 pct at T.Gd = 0 ppm to the maximum value of 99.9 pct at T.Gd = 730 ppm. At the cutting speeds of 110 and 280 r/min−1, the formation of C-type chips was observed since the hole around the inclusion was expanded through the full rolling of the spherical sulfide, while long chips were found due to the hole around sulfides being hardly expanded at the high cutting speeds of 350 and 560 r/min−1 as T.Gd = 462 ppm and 730 ppm, which resulted in the improvement of the machinability of the steel. The wear of the tool was negatively related to hardness of the steel matrix. In the steel with 462 ppm T.Gd, the surface roughness was the lowest and the tool wear was the smallest.