Effect of Ar Purification on Microstructure and Properties of High Strength Gray Cast Iron

2011 ◽  
Vol 266 ◽  
pp. 241-245
Author(s):  
Juan Yang ◽  
Sheng Xin Liu ◽  
Qi Fei Hou ◽  
Hua Wei Sun ◽  
Yu Fu Sun ◽  
...  

The effects of Ar purification on the impurity characteristic, graphite morphology and quality indexes of high strength gray cast iron were investigated by microstructures analysis and mechanical properties examination. The results show that there are a large amount of particles and floccule impurities in the specimens without Ar purification. The granular impurities usually have been incorrectly considered as “C-type” graphite observed by optical microscopy in the metallographic examination in the practical production of small and medium high strength gray cast iron castings. The amount of impurities is greatly decreased and the quality indexes of high strength gray cast iron with Ar purification are markedly improved.

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 ◽  
2021 ◽  
Vol 70 (9) ◽  

Abstract ISO 185/JL/350 is a higher-tensile-strength gray cast iron that has a pearlitic matrix, and a tensile strength of 350–450 MPa (51–65 ksi), when determined on test pieces machined from separately cast, 30 mm (1.2 in.) diameter test bars. It provides a combination of high strength while still maintaining good thermal conductivity compared with other types of cast iron. This grade approaches the maximum tensile strength attainable in gray cast iron. Applications therefore tend to be confined to those where thermal conductivity requirements in service preclude the use of one of the other higher-strength materials such as spheroidal graphite cast irons, which have inferior thermal properties. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on wear resistance as well as casting and heat treating. Filing Code: CI-85. Producer or source: International Organization for Standardization.


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.


2013 ◽  
Vol 800 ◽  
pp. 221-224
Author(s):  
Jun Tao Zhang ◽  
Feng Zhang Ren

The increase of the strength of gray cast iron is mainly depended on alloying. However, with the improvement of strength, its processing performance will always decrease. So three different gray cast irons are studied in this experiment, including adding 0.1% Nb elements, adding 0.2% Nb elements and adding 0.3% Nb elements, to investigate the Nbs effect to the mechanical performance of gray cast iron, we adopt Dynamic Strain Amplifier to measure cutting force to evaluate processing performance, use Optical Microscope and Electron Microscopy observe each samples organization, explains the relationship between Nbs content and the mechanical and processing performance of gray cast iron from micro-level. Finally, we draw the conclusion: when the Nb comes to 0.3 percent, the appearance of E-type graphite and Nb carbide durum granular will greatly decrease its processing performance.


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