Mechanical and Fatigue Properties of Heavy Section Solution Strengthened Ferritic Ductile Iron Castings

2016 ◽  
Vol 18 (12) ◽  
pp. 2070-2075 ◽  
Author(s):  
Thomas Borsato ◽  
Paolo Ferro ◽  
Filippo Berto ◽  
Carlo Carollo
Keyword(s):  
Ductile Iron ◽  
Fatigue Properties ◽  
Iron Castings ◽  
Heavy Section

scholarly journals Experimental Evidence for Metallurgical Modification Associated to Chunky Graphite in Heavy-Section Ductile Iron Castings

2012 ◽  
Vol 6 (1) ◽  
pp. 35-42 ◽  
Author(s):  
J. Lacaze ◽  
I. Asenjo ◽  
S. Méndez ◽  
J. Sertucha ◽  
P. Larrañaga ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Ductile Iron ◽  
Iron Castings ◽  
Heavy Section ◽  
Chunky Graphite

Effect of Yttrium-Containing Nodulizer on the Microstructure Formation and Mechanical Properties of Heavy Section Ductile Iron Castings

2010 ◽  
Vol 457 ◽  
pp. 73-78 ◽  
Author(s):  
Qin Xin Ren ◽  
Ming You ◽  
Yun Bang Yao ◽  
Guang Min Wen ◽  
Qi Zhou Cai
Keyword(s):  
Mechanical Properties ◽  
Ductile Iron ◽  
Graphite Nodule ◽  
High Melting ◽  
Microstructure Formation ◽  
High Melting Point ◽  
Iron Castings ◽  
Heavy Section ◽  
Long Time ◽  
Pearlite Content

Ductile iron specimens with dimensions of 400mm×400mm ×450mm were prepared by treating the melt with an yttrium-containing nodulizer. The effect of yttrium on microstructure and mechanical properties was investigated, and the formation of degenerate graphite was discussed as well. The results show that the yttrium-containing nodulizer has good nodulization fading resistance for heavy section ductile iron, since the high melting point hexagonal oxide Y2O3 particles were formed from the nodulizer in the melt and those could act as heterogeneous nuclei for graphite nodule for a long time. Segregation of Ti and MgO at grain boundaries broke the austenite shell, resulting in graphite degeneration. When heavy section ductile iron castings with pearlite matrix were cast, graphite nodule size became finer and the nodularity of graphite nodules improved due to the addition of 0.01wt% Sb to the melt, and pearlite content in specimens increased due to alloying with Cu, Cr, Mo. The heavy section ductile iron tool bed was fabricated by treating the melt with the yttrium-containing nodulizer and Ni. The nodularity of the attached block was 85%~90%, tensile strength, elongation and impact toughness were 440MPa, 23.3% and 5.0J/cm2 respectively.

scholarly journals Effect of Solidification Time on Microstructural, Mechanical and Fatigue Properties of Solution Strengthened Ferritic Ductile Iron

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 24 ◽  
Author(s):  
Thomas Borsato ◽  
Paolo Ferro ◽  
Filippo Berto ◽  
Carlo Carollo
Keyword(s):  
Mechanical Properties ◽  
Ductile Iron ◽  
Fatigue Tests ◽  
Solidification Time ◽  
Fatigue Properties ◽  
Matrix Structure ◽  
Green Sand ◽  
Cast Sample ◽  
Iron Castings ◽  
Scanning Electron

Microstructural, mechanical, and fatigue properties of solution strengthened ferritic ductile iron have been evaluated as functions of different solidification times. Three types of cast samples with increasing thickness have been produced in a green sand automatic molding line. Microstructural analyses have been performed in order to evaluate the graphite nodules parameter and matrix structure. Tensile and fatigue tests have been carried out using specimens taken from specific zones, with increasing solidification time, inside each cast sample. Finally, the fatigue fracture surfaces have been observed using a scanning electron microscope (SEM). The results showed that solidification time has a significant effect on the microstructure and mechanical properties of solution strengthened ferritic ductile iron. In particular, it has been found that with increasing solidification times, the microstructure becomes coarser and the presence of defects increases. Moreover, the lower the cooling rate, the lower the tensile and fatigue properties measured. Since in an overall casting geometry, same thicknesses may be characterized by different microstructures and mechanical properties induced by different solidification times, it is thought that the proposed methodology will be useful in the future to estimate the fatigue strength of cast iron castings through the numerical calculation of the solidification time.

scholarly journals Microstructural Adjustment of the Degenerated Graphite Layer in Ductile Iron for Targeted Evaluation on the Fatigue Properties

2020 ◽  
Vol 14 (4) ◽  
pp. 1183-1194
Author(s):  
A. Kutz ◽  
P. Martin ◽  
A. Bührig-Polaczek
Keyword(s):  
Fatigue Resistance ◽  
Ductile Iron ◽  
Fatigue Testing ◽  
Fatigue Properties ◽  
Graphite Layer ◽  
Iron Matrix ◽  
Experimental Procedure ◽  
Microstructural Defect ◽  
Casting Skin ◽  
Iron Castings

Abstract Graphite degeneration is the most prominent microstructural defect in the casting skin of ductile iron. Induced by either sulfur or oxygen contained in the molding material, its occurrence can be observed in a large range of iron castings, having substantial negative influences on the mechanical properties, especially fatigue resistance. Previous investigations predominately focused on the influence of the degenerated graphite layer, while accompanying changes of the iron matrix were neglected. The superposition of these effects hinders the evaluation of casting skin defects in state-of-the-art design of ductile iron components. The presented solution utilizes an experimental procedure, which enables the production of specimens with specific, individual microstructural configurations in the casting skin. This approach is based on the application of a modified sand core coating. By adding sulfurizing additives to the coating and adjusting its binder content and viscosity, a predominately homogeneous degenerated layer of 0.5 mm thickness was obtained. Using specific heat treatment steps assured a fully ferritic or pearlitic iron matrix, isolating the degenerated layer as the main microstructural defect. Fatigue testing of these specimens will further enable the numerical evaluation of the fatigue resistance in dependence of the casting skin microstructure.

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