Failure Analysis of the Gray Cast Iron Drain Valve of the Converter Gas Pipe

2016 ◽  
Vol 853 ◽  
pp. 468-472
Author(s):  
Guo Xin Zhang ◽  
Jun Nan Niu ◽  
Tai Rui Zhang ◽  
Yan Liu ◽  
Wei Qiang Wang
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Tensile Tests ◽  
Gray Cast ◽  
Composition Analysis ◽  
Element Analysis ◽  
Valve Body ◽  
Chemical Company ◽  
Metallographic Observation ◽  
Fracture Appearance

The valve cover of a gray cast iron drain valve, used by a chemical company, cracked during its operation. The cracking reasons of the valve cover were investigated by fracture appearance observation of the valve cover, metallographic observation, SEM observation, chemical composition analysis of the corrosion products, finite element analysis of the valve cover by ABAQUS and tensile tests and impact tests of the cover sample at normal temperature and-12°C. After these investigation jobs, it can be concluded that there was no any significant cast defect or original defect in the fracture of the valve cover, the stress was much lower than the strength of valve cover material, and the cracking of the valve cover was caused by the expansion of the ice which was changed from the seeper between the valve cover and valve body when the weather temperature was lower than-12°C. At the end of this article, some proposals were put forward to the company in order to avoid similar accidents.

Dimensional Changes of Graphite Flakes and Fracture in Tensile Tests of Gray Cast Iron

2018 ◽  
Author(s):  
Naoya Tada ◽  
Takeshi Uemori
Keyword(s):  
Cast Iron ◽  
Tensile Test ◽  
Internal Combustion Engines ◽  
Gray Cast Iron ◽  
Early Stage ◽  
Dimensional Change ◽  
Tensile Tests ◽  
High Ratio ◽  
Gray Cast ◽  
Dimensional Changes

Gray cast iron has been used as a component in various mechanical parts, such as the blocks and heads of automobile and marine engines, cylinder liners for internal combustion engines, and machine tool bases. It is desirable because of its good castability and machinability, damping characteristics, and high ratio of performance to cost. On the other hand, the weak graphite flakes present in gray cast iron act as stress concentrators and negatively affect the strength of this material. It is therefore important to know the relationship between the distribution of graphite flakes and the strength or fracture of gray cast iron. In this study, a tensile test of gray cast iron was carried out using a plate specimen in a scanning electron microscope, and the microscopic deformation was observed on the surface of specimen. Particularly, the change in the size of graphite flakes during the tensile test was examined, and the observed trend was discussed. We found from the experimental results that the dimensional changes in the graphite flakes varied in the observed area, and that the final fracture occurred in an area where a relatively large dimensional change was observed. This suggests that the fracture location or the critical parts of gray cast iron, can be predictable from the dimensional changes of the graphite flakes at an early stage of deformation.

Effect of Carbon Content on Microstructure and Properties of Gray Cast Iron

2014 ◽  
Vol 971-973 ◽  
pp. 44-48
Author(s):  
Ya Li Sun
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Carbon Content ◽  
Liquid Iron ◽  
Gray Cast Iron ◽  
Gray Cast ◽  
Carbon Equivalent ◽  
Microstructure And Properties ◽  
Metallographic Observation ◽  
Equivalent Control

Though the study of carbon content on the microstructure and properties of gray cast iron, mechanical properties test as well as metallographic observation, we could see that the mobility of molten iron is the best when carbon equivalent control at around 4.3%; Liquid iron tend to precipitate A or B type graphite and enhance the casting organization and property when carbon content was increased properly.

scholarly journals Prediction of the Fracture Location by Tensile Tests of Gray Cast Iron Based on the Dimensional Changes of Graphite Flakes

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Naoya Tada ◽  
Takeshi Uemori ◽  
Junji Sakamoto
Keyword(s):  
Cast Iron ◽  
Internal Combustion Engines ◽  
Gray Cast Iron ◽  
Early Stage ◽  
Tensile Tests ◽  
Gray Cast ◽  
Material Strength ◽  
Cost Ratio ◽  
Dimensional Changes ◽  
Fracture Location

Abstract Gray cast iron has been used as a component in various mechanical parts, such as the blocks and heads of automobile and marine engines, cylinder liners for internal combustion engines, and machine tool bases. It is desirable because of its good castability and machinability, damping characteristics, and high performance-to-cost ratio. On the other hand, weak graphite flakes present in gray cast iron serve as stress concentrators and adversely affect the material strength. Therefore, it is crucial to examine the relationship between the distribution of graphite flakes and the strength or fracture of gray cast iron. In this study, tensile tests on gray cast iron were carried out using a plate specimen and observed by scanning electron microscopy, and the microscopic deformation was observed on the specimen surface. Particularly, the change in the size of graphite flakes during the tensile tests was examined, and the observed trend was discussed. The experimental results reveal that the dimensional changes in the graphite flakes vary in the observed area and that the final fracture occurs in an area where a large dimensional change is observed, suggesting that the fracture location or critical parts of gray cast iron can be predicted from the dimensional changes of the graphite flakes at an early stage of deformation.

Teknologi Inokulasi Besi Cor Kelabu FC-250 Untuk Mencegah Pengerasan Pada Dove Tale Produk Ragum Tipe 125

2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Amin Suhadi ◽  
Seodihono
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Treatment Process ◽  
Gray Cast Iron ◽  
Spare Parts ◽  
Gray Cast ◽  
Micro Structure ◽  
Control Factors ◽  
Seed Inoculation ◽  
Casting Industry

Production technology of metal casting industry in Indonesia needs to be improved, especially in the manufacturing of spare parts and box engine made of gray cast iron which has various wall thick such as dove tale construction. Microstructure of gray cast iron is influenced by cooling rate during casting, chemical composition and melting treatment process (inoculation). The part which has the thinnest thickness has the fastest cooling therefore, the grain boundary is smaller compared to other section. As a result this part has highest hardness and difficult to be machined. This research is conducted to solve this problem by modifying melting and solidification treatment process. The research starting from micro structure analysis, composition and mechanical properties tests on the product, and then conducting modification treatment through Taguchi method approach. Experimental results obtained show that the best level settings to control factors which affect to the uniformity of the microstructure and mechanical properties in gray cast iron is the addition of seed inoculation super ® 75, as much as 0.25% with the method of inoculation material entering into the Transfer Ladle.Teknologi produksi pada industri pengecoran di Indonesia masih membutuhkan perbaikan terutama dalam pembuatan komponen mesin perkakas dan peralatan pabrik yang terbuat dari besi tuang kelabu yang mempunyai variasi ketebalan yang besar seperti konstruksi ekor burung (dove tale). Pada pengecoran, struktur mikro dari besi tuang kelabu sangat dipengaruhi oleh kecepatan pendinginan, komposisi kimia dan proses perlakuan pada logam cair (inokulasi). Bagian yang mempunyai ukuran paling tipis mempunyai kecepatan pendinigan paling tinggi karena itu ukuran butirnya jauh lebih kecil dari bagian lain, akibatnya bagian ini mempunyai kekerasan lebih tinggi dan sulit dilakukan pengerjaan mesin. Penelitian ini bertujuan untuk memperbaiki hal ini yang terjadi pada dove taledengan cara memodifikasi proses perlakuan pada cairan besi dan proses pendinginan. Penelitian dimulai dari analisa struktur mikro, pengujian komposisi kimia, pengujian sifat mekanis pada produk kemudian dilakukan modifikasi menggunakan pendekatan metode statistik Taguchi. Hasil penelitian menunjukkan bahwa pengaturan terbaik yang dapat diperoleh untuk mendapatkan keseragaman struktur mikro dan sifat mekanis pada pengecoran besi tuang kelabu adalah penambahan seed inoculation super ® 75, sebesar 0.25% dengan metode pemasukan inokulasi kedalam Ladle pengangkut logam cair.Keywords: carbon, micro structure, hardness, inoculation

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