Kusiak Tomasz, Tomczak Janusz, Wójcik Jarosław
Department of Metal Forming, Mechanical Engineering Faculty, Lublin University of Technology, 20-618 Lublin, Poland.
Materials (Basel). 2024 Sep 17;17(18):4558. doi: 10.3390/ma17184558.
This paper presents selected results of theoretical and experimental research into the manufacture of axisymmetric bimetallic components using three-tool skew rolling technology. In the tests, it was assumed that the outer layer would be a material intended for heat treatment. However, low-carbon steel was used for the core. Experimental investigations were carried out in an innovative CNC skew rolling mill. Tests were carried out at different technological parameters of the process. In addition, the geometric parameters of the billet and the way it was heated were analyzed in relation to the quality of the resulting weld between the two materials. The quality of the weld was assessed based on metallographic observation and on strength tests (shear method). On the other hand, theoretical studies were based on numerical modeling (FEM). The numerical analysis made it possible to determine the distribution of temperature, deformation and stress in the rolling bimetallic component. The results obtained indicated that it is possible to produce bimetallic materials from the proposed steel grades. In addition, a significant effect of the method of heating the billet in the chamber furnace on the microstructure in the joining zone and the shear strength was found. There was an increase in Rc strength of about 35% when using oxidation protection. The results indicated better strength when the billet is rolling with a smaller outer layer thickness (about 50 MPa). This was confirmed by the results obtained from the FEM analysis, which indicated higher values of plastic strain and the occurrence of higher compressive stresses in the near-surface zones of the rolled bimetallic forging, both of which facilitate the welding process. From the temperature distribution (in the range of (600-1200) °C) obtained during the rolling of the bimetal forging, it can be seen that contact with cold tools does not affect the temperature in the welding zone.
本文介绍了使用三工具斜轧技术制造轴对称双金属部件的理论和实验研究的部分结果。在试验中，假定外层将采用适合热处理的材料。然而，芯部使用的是低碳钢。实验研究在一台创新型数控斜轧机上进行。试验在该工艺的不同技术参数下开展。此外，分析了坯料的几何参数及其加热方式对两种材料之间最终焊缝质量的影响。基于金相观察和强度试验（剪切法）对焊缝质量进行了评估。另一方面，理论研究基于数值模拟（有限元法）。数值分析使得确定轧制双金属部件中的温度、变形和应力分布成为可能。所得结果表明，用所提议的钢种能够生产双金属材料。此外，发现坯料在室式炉中的加热方式对连接区的微观结构和剪切强度有显著影响。使用氧化保护时，洛氏硬度强度提高了约35%。结果表明，当坯料轧制时外层厚度较小时（约50兆帕）强度更高。有限元分析所得结果证实了这一点，该分析表明轧制双金属锻件近表面区域的塑性应变值更高，且出现更高的压应力，这两者都有利于焊接过程。从双金属锻件轧制过程中获得的温度分布（在(600 - 1200)℃范围内）可以看出，与冷工具接触不会影响焊接区的温度。
