Flake Graphite Cast Iron Research Articles

EFFECT OF MAGNESIUM TREATMENT PROCESS ON THE PRODUCING COMPACTED GRAPHITECAST IRON WITH DIFFERENT CASTING THICKNESS

Strength, toughness, machinability and damping capacity are properties of compacted graphite iron that distinguish the properties between flake graphite cast iron and spheroidal cast iron. The formation of compacted graphite can be set to achieve the required specification. The formation of compacted graphite is started from spheroidal to compacted cast iron. The residual magnesium after magnesium treatment and the solidification ratehave a significant role in the formation of compacted graphite. The high content of residual magnesium can obstruct the graphite plane to grow during the transformation from spheroidal to compacted shape. In addition, the cooling rate of the casting can be controlled by varying the casting thickness. The compacted graphite in the cast iron are characterized according to shape, size ai`nd distribution. The optimum compacted graphite in the cast iron that can be produced has 30 mm of casting thickness with 0.017 % of residual magnesium.

Analysis of the Microstructure and Hardness of Flake Graphite Cast Iron Using the Barkhausen Noise Method and Conventional Techniques

The new brake disc was evaluated for microstructure and hardness by the conventional destructive tests and non-destructive Barkhausen noise method (BNM). Ten non-destructive measurements were carried out in different areas of a brake disc, which were then cut out and made into metallographic test samples. Qualitative and quantitative analysis of graphite precipitates was performed to assess their volume in material matrix, anisotropy and size. Subsequently, graphs showing the relationships between selected stereological parameters of graphite precipitates and parameters determined from the RMS envelope of Barkhausen noise were elucidated. Similar relationships between hardness and parameters coming from non-destructive tests were carried out. Magnetic parameters that specified the size of a graphite precipitate was selected. In addition, repeatability studies using BNM were carried out in the areas of the material with the smallest and largest average size of graphite precipitates. A linear relationship between amplitude of BN and length of graphite flakes was found. The paper presents the possibilities of assessing the volume and size of graphite precipitates, as well as cast iron hardness using BNM.

Experimental visualization of the wear and scuffing evolution of a flake graphite cast iron cylinder liner

Scuffing is a wear mechanism that can lead to catastrophic failure of various technical applications. Even though the mechanism has been researched in countless publications for decades, it is not fully understood yet. An experimental approach was used in this paper to investigate the origin and evolution of scuffing in a ring-on-liner contact. For this purpose, test runs in an application-oriented test rig were stopped at different points in time. A linear tribometer was used to transfer a reciprocating motion of a real piston ring segment to a specimen made from a real cylinder liner. Based on a comprehensive analysis, a four-stage scuffing hypothesis for a ring-on-liner contact was developed. In the first stage, smearing of the honing structure and the formation of surface cracks lead to the development of a scaly structure on the liner surface. Crack growth induced by adhesive shear forces leads to the formation of breakouts in the liner surface in the second stage. Both stages are stable and only the specific load increase of the used test strategy causes the transition to stage three. Here, large crack growth induced breakouts result in the local destruction of tribofilms and, subsequently in local metallic contact between the specimens. When this local destruction becomes rampant and expands to a macro scale, adhesive bonds lead to macroscopic scuffing. It can be deduced that the first occurring damage stage is a result of a surface fatigue process.

Effect of Mn Content on Fatigue Limit of Various Flake Graphite Cast Irons

In recent years, with the active use of Mn-containing high-tensile strength steels as an automotive body material, it has become increasingly difficult to recycle Mn-containing high tensile strength steel scrap as raw material to produce cast iron, due to the fact that Mn is known as an element promoting the chilling tendency of cast iron melt. Therefore, in this study, the effect of Mn on the fatigue limit of flake graphite cast iron was investigated for the purpose of increasing the strength of cast iron and recycling high tensile strength steel. Flake graphite cast irons with different Mn contents (0.5 mass % and 2.0 mass %, the carbon equivalent corresponding to FC200, FC300 and FC400 of JIS specification (G 5501)) were prepared for plane bending fatigue test.

Dynamic pressure scuffing initiation of a grade 250 flake graphite cast iron

The dynamic contact pressures experienced at the ring-liner interface of an engine are difficult to replicate in laboratory based reciprocating tribometers utilising a sliding Hertzian line contact, not least due to wear of the mating surfaces. A grade 250 flake graphite cast iron flat plate test geometry was designed to allow dynamic contact pressures between 8 and 62 MPa experienced in a heavy-duty diesel engine liner to be achieved on a reciprocating tribometer during the compression and expansion stroke.A constant normal load of 311 N was applied by sliding at 25 mm stroke length in PAO4 at 15 Hz against a 52100 rectangular contact area (2 × 20 mm). The temperature was slowly increased at 4 °C/min to initiate scuffing between the mating surfaces. Severe scuffing initiated at 250.8 ± 2.6 °C for all specimens. The spatially resolved friction force and non-contact optical profilometry suggested scuffing did not always initiate in the region of the highest contact pressure, whilst electron microscopy revealed that subsequent to lubricant failure, a transient low friction iron oxide layer was formed prior to removal and catastrophic adhesive wear.

Effect of SiC Addition on Mechanical Properties of Flake Graphite Cast Iron

Effect of SiC Addition on Mechanical Properties of Flake Graphite Cast Iron

Fatigue strength and notch sensitivity of high-manganese flake graphite cast iron

To increase the recovery rate of high-tensile-strength steel (HTSS) scrap, the effect of manganese (0.5% and 2.0% Mn) on the fatigue properties of several flake graphite cast iron (FGI) samples is investigated, along with the thickness and notch sensitivity of high-manganese (Hi-Mn) FGIs. The results reveal an increase in the pearlite fraction, an increase in the crystallization of Type-A graphite, and a decrease in the interlamellar spacing owing to the addition of Mn, which results in a significant increase in fatigue strength. Moreover, Mn does not worsen the notch sensitivity of the Hi-Mn FGIs. However, Hi-Mn FGIs have a higher thickness sensitivity because a longer cooling time results in wider interlamellar spacing and increased graphite length. Overall, HTSS can be recycled as a raw material for Hi-Mn FGIs without removing Mn, and Hi-Mn FGIs can be used for thinner parts with high-fatigue-strength requirements.

Variable pressure scuffing of a flake graphite cast iron diesel cylinder liner

A novel scuffing methodology was developed utilising variable specimen geometry to replicate numerically modelled top compression ring contact pressures (4–62 MPa) from a 12.8-litre heavy duty diesel engine as a function of stroke position. Scuffing of grade 250 cast iron was induced by reciprocating sliding (TE77) against a drip lubricated (PAO4) 52100 rectangular contact operating at 15 Hz and 311 N normal load by incrementing the temperature at 4°C per minute until a sharp rise in friction coefficient was observed. Scuffing initiation temperature was insensitive to dynamic contact pressure. Formation of an oxide ‘glaze’ layer resulted in friction coefficients as low as 0.03 prior to severe scuffing.

Effect of Mn Content on Fatigue Limit of Various Flake Graphite Cast Irons

Effect of Mn Content on Fatigue Limit of Various Flake Graphite Cast Irons

Effects of Inoculation with Alkaline Earth and Rare Earth Elements on Graphitization and Mechanical Properties in High Manganese Flake Graphite Cast Iron

Effects of Inoculation with Alkaline Earth and Rare Earth Elements on Graphitization and Mechanical Properties in High Manganese Flake Graphite Cast Iron

Effects of Al addition and heat treatment on microstructure and damping capacity of flake graphite cast iron

Effects of Al addition and heat treatment on microstructure and damping capacity of flake graphite cast iron

EFFECT OF MAGNESIUM TREATMENT PROCESS ON THE PRODUCING COMPACTED GRAPHITE CAST IRON WITH DIFFERENT CASTING THICKNESS

Strength, toughness, machinability and damping capacity are properties of compacted graphite iron that distinguish the properties between flake graphite cast iron and spheroidal cast iron. The formation of compacted graphite can be set to achieve the required specification. The formation of compacted graphite is started from spheroidal to compacted cast iron. The residual magnesium after magnesium treatment and the solidification rate have a significant role in the formation of compacted graphite. The high content of residual magnesium can obstruct the graphite plane to grow during the transformation from spheroidal to compacted shape. In addition, the cooling rate of the casting can be controlled by varying the casting thickness. The compacted graphite in the cast iron are characterized according to shape, size and distribution. The optimum compacted graphite in the cast iron that can be produced has 30 mm of casting thickness with 0.017 % of residual magnesium. 

片状黒鉛鋳鉄のK-FGI 及び肥痩度と引張強さ, 硬さ, 熱伝導率との関係

片状黒鉛鋳鉄のK-FGI 及び肥痩度と引張強さ, 硬さ, 熱伝導率との関係

Improving Accuracy of Graphite Form Measurement in Flake Graphite Cast Iron

Improving Accuracy of Graphite Form Measurement in Flake Graphite Cast Iron

Effect of Carbon Equivalent and Cooling Rate on Chilling Tendency and Mechanical Properties in Flake Graphite Cast Iron with different Mn contents

Effect of Carbon Equivalent and Cooling Rate on Chilling Tendency and Mechanical Properties in Flake Graphite Cast Iron with different Mn contents

Various Quantitative Classification Methods for Graphite Structure of Flake Graphite and Spheroidal Graphite Cast Iron

Various Quantitative Classification Methods for Graphite Structure of Flake Graphite and Spheroidal Graphite Cast Iron

Relationship Between Various Numerical Values Obtained from Cooling Curve and Graphite Shape for Flake Graphite Cast Iron

Relationship Between Various Numerical Values Obtained from Cooling Curve and Graphite Shape for Flake Graphite Cast Iron

Sand-sodium-silicate mixtures structured in steam-microwave environment effective values of thermo-physical properties

Purpose. Sand-sodium-silicate mixtures, structured by steam-microwave solidification, thermo-physical properties integral-effective values during Al-Mg alloy and graphite cast iron pouring determination. Sand-sodium-silicate mixture apparent density changing according to quartz sand, cladded with sodium silicate solute, fractional composition and its influence on BrA9Zh3L bronze microstructure establishment. Methodology. Quartz sand with 0.23 mm average particle size, sodium silicate solute, aluminum alloy with 8.5% Mg, flake graphite cast iron SCh200 (DSTU 8833:2019), bronze BrA9Zh3L (GOST 493-79) were used. Mixtures structuring was carried out in 700 W magnetron power microwave furnace. Sand-sodium-silicate mixture thermo-physical properties integral-effective values were calculated by G.A.Anisovich method, using castings results and molds thermography. Structured mixtures apparent density was determined on samples 50 120 mm dimension. Metallographic studies were realized using Neophot-21 optical microscope. Findings. It was found that with sodium silicate solute, used for sand cladding, amount increasing from 0.5 to 3% mold material apparent density decreases and thermal activity lowers. This leads to castings grains size increasing. Mixture sodium silicate solute content was recommended limiting 1.5% for fine-grained microstructure castings obtaining and cladded sand using, which particles pass through mesh side less 0.315 mm sieve. Sands with sodium silicate solute content more than 1.5%, which dont pass through sieve 0.4 mm mesh side, were recommended as casting molds heat-insulating material using. Originality. For the first time, when aluminum-magnesium alloy and graphite cast iron pouring, quartz sand cladded with sodium silicate solute in amount from 0.5 to 3.0% (weight, over 100% quartz sand), steam-microwave radiation structured, thermo-physical properties integral-effective values were determined. Practical value. Data obtained using will improve castings solidification time and rate analytical calculations accuracy, forecast level and residual stresses sign in them, shrinkage defects locations. This will reduce casting technology developing time and costs and castings manufacturability.

Development of Quantitative Graphite Evaluation Method for Flake Graphite Cast Iron by Image Analysis

Development of Quantitative Graphite Evaluation Method for Flake Graphite Cast Iron by Image Analysis

Damping Characteristics of Three-dimensional Co-continuous Network Graphite / Cast Steel Composites

The infiltration casting method is used for the preparation of three-dimensional co-continuous network structure of graphite/cast steel composite material in atmospheric pressure. Using modal analysis method, flake graphite cast iron specimen and composite sample are compared about damping factors. The results show that amplitude attenuation of the composite material is more quickly than that of flake graphite cast iron specimens. Supported in two rigid points state, the first step damping ratio of the composite material is 2.1 times of flake graphite cast iron. At the same time, its tensile strength is 1.54 to 1.68 times that of flake graphite cast iron, its hardness reaches more than 86%, and its bulk density is reduced to less than 94%. The composite not only has good vibration damping and anti-friction performance, but also has comprehensive mechanical properties exceeding the level of flake graphite cast iron. It is possible to replace flake graphite cast iron for manufacturing important mechanical equipment castings such as fuselage and guide rail to obtain better anti-wear / vibration damping effect.