scholarly journals Influence of Microscopic Effects on the Static Tensile Strength of Gray Cast Iron HT200 Specimens

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
L. Fan ◽  
H. B. Hu ◽  
X. S. Tang ◽  
J. J. He ◽  
W. Chen

Gray cast iron HT200 material is a kind of pearlitic gray cast iron. Flake graphite in the gray cast iron greatly destroys the integrity of the matrix and affect the static strength. The influence of microscopic effects on the tensile static strength of gray cast iron HT200 specimens is investigated. The microstructures are observed by the scanning electron microscope. The failure tests are done under the static loads for the cylinder specimens of gray cast iron HT200. Then, an energy density zone (EDZ) model is applied to the simulation of the fracture process of the specimens. The energy density zone model is a macro/micro-trans-scale crack growth model that can depict a fracture process from an initial microdefect at the microscale to the final break at the macroscale. Three scale transitional functions as well as the size of the initial microdefect in the model represent the microscopic effects in a fracture process. Three scale transitional functions are speculated in view of the physical failure mechanisms. Two other material parameters in the model are determined from the test data. Thereby, the fracture process of gray cast iron specimens is numerically simulated, and the static strength values are calculated. The calculated values of static strength of gray cast iron specimens are identical to the test values. It is seen that the energy density zone model can accurately describe a fracture process of brittle materials like gray cast iron. In addition, the calculated results show that the microscopic effects did affect the static strength of gray cast material.

Author(s):  
Edney Deschauer Rejowski ◽  
Edmo Soares ◽  
Ingo Roth ◽  
Steffen Rudolph

With the increase of combustion loading and the trend to reduce engine size, there is a need for thinner but stronger wet cylinder liners. While most of the current cylinder liners are made of gray cast iron, due to its good tribological behavior, machinability performance and competitive price, alternative casting materials like compact graphite iron, ductile iron and even steel are being considered to cover the future engine demands. In this paper, a new ductile iron (DI) cast material for wet cylinder liners is presented. The material has about 60 and 70% higher limits respectively for tensile stress and fatigue resistance as compared to conventional gray cast irons, but without penalty on the tribological properties. There is also a potential improvement to avoid cavitation on the outside surface due to its higher young modulus, which also equates to a higher stiffness. The tested cylinder liners were induction hardened on the running surface and a slide hone process was used to improve wear and scuffing resistance. The liners were tested in a HDD engine with PCP of 245 bar and showed similar wear as observed with conventional cylinder liners of gray cast iron material. The DI cylinder liners were also tested in an abusive scuffing engine test without any concern. The improved mechanical properties of the described new DI material introduce possibilities to reduce liner wall thickness or increase specific output. The preliminary evaluation in this paper showed that this new material is feasible for HDD diesel engines with PCP up to 250 bar. In cases that the customer needs to increase the bore diameter for output reasons there is the potential to reduce the liner wall thickness up to 25% based on high mechanical properties (UTS, Young Modulus and fatigue strength). In both cases, it’s recommended a FEA analysis to support the new component design.


Author(s):  
Edney Deschauer Rejowski ◽  
Edmo Soares ◽  
Ingo Roth ◽  
Steffen Rudolph

With the increase of combustion loading and the trend to reduce engine size, there is a need for thinner but stronger wet cylinder liners. While most of the current cylinder liners are made of gray cast iron, due to its good tribological behavior, machinability performance, and competitive price, alternative casting materials such as compact graphite iron, ductile iron, and even steel are being considered to address future engine demands. In this paper, a new ductile iron (DI) cast material for wet cylinder liners is presented. The material has about 60 and 70% higher limits, respectively, for tensile stress and fatigue resistance as compared to conventional gray cast irons, but without a penalty on the tribological properties. There is also a potential improvement to avoid cavitation on the outside surface due to its higher young modulus, which also equates to a higher stiffness. The tested cylinder liners were induction hardened on the running surface and a slide hone process was used to improve wear and scuffing resistance. The liners were tested in a heavy duty diesel (HDD) engine with a peak cylinder pressure (PCP) of 245 bar and showed similar wear as observed with conventional cylinder liners of gray cast iron material. The DI cylinder liners were also tested in an abusive scuffing engine test without any concern. The improved mechanical properties of the described new DI material introduce possibilities to reduce the liner wall thickness or increase specific output. The preliminary evaluation in this paper showed that this new material is feasible for HDD diesel engines with a PCP up to 250 bar. In cases where the customer needs to increase the bore diameter for output reasons there is the potential to reduce the liner wall thickness by up to 25% based on high mechanical properties (UTS, Young’s modulus and fatigue strength). In both cases, a FEA analysis to support the new component design is recommended.


2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Amin Suhadi ◽  
Seodihono

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


Alloy Digest ◽  
1973 ◽  
Vol 22 (2) ◽  

Abstract MEEHANITE GF-20 is a gray cast iron designed principally for high machinability and is used where strength is not an important factor. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: CI-39. Producer or source: Meehanite Metal Corporation.


Alloy Digest ◽  
2020 ◽  
Vol 69 (9) ◽  

Abstract ISO 185/JL/225 is an intermediate-tensile-strength gray cast iron that has a predominantly pearlitic matrix, and a tensile strength of 225–325 MPa (33-47 ksi), when determined on test pieces machined from separately cast, 30 mm (1.2 in.) diameter test bars. Compared with the lower strength gray cast iron grades, ISO 185/JL/225 contains lower carbon and silicon contents, while still maintaining excellent thermal conductivity, damping capacity, and machinability. This datasheet provides information on composition, physical properties, tensile properties, and compressive strength as well as fatigue. It also includes information on heat treating. Filing Code: CI-73. Producer or source: International Organization for Standardization (ISO).


Author(s):  
Eduard Riemschneider ◽  
Ilare Bordeasu ◽  
Ion Mitelea ◽  
Ion Dragos Utu ◽  
Corneliu Marius Crăciunescu

2003 ◽  
Vol 35 (6) ◽  
pp. 568-573 ◽  
Author(s):  
A. A. Lebedev ◽  
I. V. Makovetskii ◽  
V. P. Lamashevskii ◽  
N. L. Volchek

2020 ◽  
Vol 15 (4) ◽  
pp. 543-549
Author(s):  
Haydar Kepekci ◽  
Ergin Kosa ◽  
Cüneyt Ezgi ◽  
Ahmet Cihan

Abstract The brake system of an automobile is composed of disc brake and pad which are co-working components in braking and accelerating. In the braking period, due to friction between the surface of the disc and pad, the thermal heat is generated. It should be avoided to reach elevated temperatures in disc and pad. It is focused on different disc materials that are gray cast iron and carbon ceramics, whereas pad is made up of a composite material. In this study, the CFD model of the brake system is analyzed to get a realistic approach in the amount of transferred heat. The amount of produced heat can be affected by some parameters such as velocity and friction coefficient. The results show that surface temperature for carbon-ceramic disc material can change between 290 and 650 K according to the friction coefficient and velocity in transient mode. Also, if the disc material gray cast iron is selected, it can change between 295 and 500 K. It is claimed that the amount of dissipated heat depends on the different heat transfer coefficient of gray cast iron and carbon ceramics.


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