Especially the Transformation of Austenite in High-Strength Cast Iron during Processing

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Mechanics, Materials Science & Engineering, March 2017

ISSN 2412-5954

Especially the Transformation of Austenite in High-Strength Cast Iron during Processing With Continuous Cooling3 R.K. Hasanli 1,a, S.N. Namazov 2,b 1

Associated professor, Dr., Azerbaijan Technical University, Baku, Azerbaijan

2

Professor, Dr., Azerbaijan Technical University, Baku, Azerbaijan

a

hasanli_dr@mail.ru

b

subhan_namazov@daad-alumni.de DOI 10.2412/mmse.11.018.190 provided by Seo4U.link

Keywords: high-strength cast iron, spherical graphite, the transformation of austenite, economical alloying, chill casting, heat treatment, structure, austenite, bainite, properties.

ABSTRACT. The peculiarities of the transformation of austenite in high-strength cast iron with spherical-eminent graphite when machining with continuous cooling. The possibility of obtaining a bainite structure economically-alloyed with nickel and copper, and molded in a metal mold of high strength cast iron with continuous cooling. It is established that in high-strength cast iron processed by bainite, graphite inclusions should have a spherical shape. The amount of vermicular graphite may be in the range of 10-20%.

Introduction.The aim of this work is to study the peculiarities of the transformation of austenite in high-strength nodular cast iron when machining with continuous cooling. According to the literature recommendations, cast iron subjected to heat treatments continuous cooling to ensure it bainite structure should contain additives of Ni, Cu and Mo [1, 2]. The lack of Mo in the composition of the investigated cast irons has demanded carrying out of special research. Analyses of the Especially the Transformation of Austenite in High-Strength Cast Iron during Processing With Continuous Cooling. It is possible to assume, that the continuous air-cooling economically-alloyed cast iron transformation occurs at temperatures of 450-3500C (not lower than 3500C). The real strength of cast iron after such treatment may be 800-1100 MPa, which satisfies these requirements. Rightly considered, that the bottleneck for high-strength cast irons are a lack of ductility and toughness. However, it was found that using the chill casting method largely facilitates the solution of this problem [3-12].

Comparison of properties of high-strength cast irons carried out the casting in the mold and sandyargillaceous form an integrated doped Ni - Cu additives or Ni. Heat treatment of castings is carried out in the following mode. Heating was carried out up to temperatures of 870 100C and 900 100C with excerpts 15 and 40 min. The cooling was carried out on the tranquil air and accelerated with a blowing air jet. Quality heat treatment were evaluated by hardness and obtain the structure of the matrix. After air-cooling in the design of all cast irons are observed more or less large areas of ferrite around the graphite inclusions are spherical (Fig. 1). Such areas are enriched in silicon and this is why the process of saturation with carbon is inhibited. It is established that the increase in time of exposure at a temperature of austenitization slightly reduces the size of the ferritic regions. Determined that a small amount of ferrite (2-3%) are located

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-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/

MMSE Journal. Open Access www.mmse.xyz

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