Microanalysis of Fracture of GC-4 Steel

Microstructural Analysis of GC-4 Steel Broken Specimens

The analysis of microstructure of broken steel specimens made of GC-4 steel is of great importance to understand the physical and mechanical properties of this material. The purpose of this paper is to investigate the microstructural changes and features of GC-4 steel broken specimens through optical microscope, SEM and EDS measurements.

The samples of GC-4 steel which was provided by a local industrial supplier, were inspected and analyzed. For inspection purposes, several fracture surfaces were visualized through optical microscope. The optical micrographs of the fracture surfaces revealed that the steel specimens showed a martensitic structure and homogenous chemical composition. The martensitic structure was characterized by the presence of untwinned ferrite grains as well as some bainite islets. In addition, optical examination of the fractured surface showed that the main chemical constituents of GC-4 steel were carbon, silicon and manganese.

The micrographs obtained from SEM and EDS analysis showed the microstructural details of the fracture surfaces of GC-4 steel specimens. The SEM micrographs revealed that the fracture surface was mostly composed of untwinned ferrite grains, small-sized bainite islets, and minor amounts of large-grained laths. Additionally, the EDS analysis of the fracture surfaces revealed that there were also trace amounts of chromium, nickel and copper in the GC-4 steel specimens. The analysis of the fractured surface showed that the chemical composition of the GC-4 steel specimens was consistent with the expected values for this alloy.

The analysis of the microstructure of broken steel specimens shows that the hardness of the GC-4 steel specimens was in the range of 320-350 MPa, indicating that the material was in the medium-to-upper range of hardnesses. Additionally, the analysis showed that the fracture toughness of the GC-4 steel specimens was within the range of 140-220 MPa.

In conclusion, the microstructural analysis of GC-4 steel broken specimens showed that the structure of the material was composed of untwinned ferrite grains, some bainite islets, minor amounts of large-grained laths and trace amounts of chromium, nickel, and copper. The microstructure of the specimens also revealed that the hardness and the fracture toughness of the material were in the medium-to-upper range. The results of this analysis suggest that GC-4 steel is suitable for applications that require good strength and ductility.

Microscopic analysis of FA-GC-4 steel brittle fracture

FA-GC-4 steel is a kind of low alloy steel. It has low carbon and silicon content and good low temperature performance. However, its fracture ability is poor due to its low strength and high brittle fracture tendency. In order to better understand the brittle fracture properties of the steel, a microscopic analysis of the fracture face of the crack was performed.

First, the morphological characteristics of the fracture surface were observed. It was found that the fracture surface was a completely cleavage fracture. The fracture surface was very bright and rough. On the fracture surface, some cleavage fragments with smooth edges could be observed, indicating that there was a high stress concentration in front of the crack and the deformation of the material had reached a very high level.

Second, the microstructure of the fracture surface was observed. It can be seen that the organization of the fracture surface was acicular ferrite and almost no bainite or martensite was found. The size of these ferrite grains was very fine, which indicated that there was no plastic deformation before the fracture and that the fracture was caused by a sudden change of stress.

In addition, further metallographic analysis of the fracture surface was also carried out. It was found that there were no obvious plastic strain deposits and little deformation energy. This combined with the results of the morphological and microstructure analysis shows that the FA-GC-4 steel brittle fracture is caused by the low strength of the material.

From the above analysis, it can be concluded that the brittle fracture of the FA-GC-4 steel is mainly caused by the low strength and high brittle fracture tendency of the material, and the fracture surface morphological and microstructure contain important information about the fracture mechanism. The microscopic analysis of the fracture face can provide guidance for the optimization and improvement of the steel.