A Basic Study on the Fatigue Reliability of the Spheroidal Graphite Iron with High Tension and Toughness. 1st Report. A Fractographic Study on the Influence of the Matrix Structure on the Fatigue Limit under Axial Loadings.

The microstructures and mechanical properties of a sector ductile iron casting with a wall thickness of 500 mm were investigated. Results show that spheroidal graphite is obtained in ductile iron, and chunky graphite is avoided because of chills used during solidification. Besides, the matrix structure is nearly a full ferrite structure at the edge of casting while some pearlite forms at the center of casting. The competing effect between graphite and matrix structure keeps the strength relatively inert to the change in solidification time or cooling rate, but these two parameters both impair elongation of ductile iron as well. The samples with full ferrite matrix exhibit a typical ductile fracture mode while those with some pearlite lead to a mixed ductile-brittle fracture mode. Graphite internal fracture or graphite/matrix interfacial cracking are two crack initiation sites.

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The Effect of Plasma-sprayed Alumina Coating on the Fatigue Limit of Spheroidal Graphite Iron, FCD 80 at Elevated Temperatures.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.57.1062 ◽

1991 ◽

Vol 57 (537) ◽

pp. 1062-1066 ◽

Cited By ~ 2

Author(s):

Hideto SUZUKI ◽

Tadashi UEKI ◽

Masahiro FUKUMOTO

Keyword(s):

Fatigue Limit ◽

Elevated Temperatures ◽

Alumina Coating ◽

Spheroidal Graphite ◽

Spheroidal Graphite Iron ◽

Plasma Sprayed

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Creep of the Matrix During Coalescence and Overgrowth of Graphite Precipitates in a High-Silicon Spheroidal Graphite Iron Submitted to Thermal Cycling in the Ferritic Domain

Metallurgical and Materials Transactions A ◽

10.1007/s11661-020-05727-y ◽

2020 ◽

Vol 51 (6) ◽

pp. 2685-2688

Author(s):

Tito Andriollo ◽

Jacques Lacaze ◽

Niels Tiedje

Keyword(s):

Thermal Cycling ◽

Spheroidal Graphite ◽

Spheroidal Graphite Iron ◽

The Matrix ◽

High Silicon

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Formation of Persistent Slip Band in Fatigued Copper Single Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100054807 ◽

1982 ◽

Vol 40 ◽

pp. 470-471

Author(s):

N. Y. Jin

Keyword(s):

Volume Fraction ◽

Fatigue Cracks ◽

Wall Structure ◽

Matrix Structure ◽

Dislocation Dipole ◽

Slip Bands ◽

Persistent Slip Bands ◽

The Matrix ◽

Hard Shell ◽

Copper Single Crystals

Localised plastic deformation in Persistent Slip Bands(PSBs) is a characteristic feature of fatigue in many materials. The dislocation structure in the PSBs contains regularly spaced dislocation dipole walls occupying a volume fraction of around 10%. The remainder of the specimen, the inactive "matrix", contains dislocation veins at a volume fraction of 50% or more. Walls and veins are both separated by regions in which the dislocation density is lower by some orders of magnitude. Since the PSBs offer favorable sites for the initiation of fatigue cracks, the formation of the PSB wall structure is of great interest. Winter has proposed that PSBs form as the result of a transformation of the matrix structure to a regular wall structure, and that the instability occurs among the broad dipoles near the center of a vein rather than in the hard shell surounding the vein as argued by Kulmann-Wilsdorf.

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Defects Reduction in Spheroidal Graphite Iron Casting Process of a Jackscrew Manufacturer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.891.174 ◽

2021 ◽

Vol 891 ◽

pp. 174-182

Author(s):

Supachart Muangyai ◽

Parames Chutima

Keyword(s):

Six Sigma ◽

Process Capability ◽

Casting Process ◽

End Users ◽

Spheroidal Graphite ◽

Iron Casting ◽

Spheroidal Graphite Iron ◽

Six Sigma Approach

This research focused on defects reduction in spheroidal graphite iron casting process of a jackscrew manufacturer in which graphite nodularity was lower than a given specification (75%). This situation could lead to serious issues and accident to end-users. The Six Sigma approach of DMAIC was employed to identify and eliminate the problems. The result obtained after implementing the Six Sigma showed that the process capability was improved from-0.47 to 2.04, and the average per cent graphite nodularity was increased significantly from 61.49% to 86.43%.

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