Globular Graphite Research Articles

Specifics of Wear of Ceramic Cutting Tool Inserts Featuring Al<sub>2</sub>O<sub>3</sub>-TiC Dies when Face Milling Hardened Cast Iron

This work studies wear kinetics of index able inserts (II) made of mixed ceramics based on Russian-manufactured in case of fine milling of special hardened cast iron with globular graphite. In a wide range of cutting parameters typical for fine milling, an impact of tool insert wearing parameters on qualitative and quantitative characteristics of the cutting process have been studied. Morphological traits and nature of wear of work surfaces has been studied using optical and scanning electron microscopy. Criteria of II states, as well as specifics of contact work surface transformation, correlating with force parameters of the face milling process, have been determined.

Comparison of Numerical Analysis of Stress-Strain States of Cast Iron with Vermicular Graphite Shape and Globular Graphite Shape

Method of final elements is highly effective modern numerical method for solving technical and scientific tasks, which is nowadays more and more used. The report deals with comparison of analysis of stress conditions on microstructure of cast iron with vermicular graphite and with cast iron type with globular graphite. Briefly describes their chemical composition, mechanical properties and structure that we will serve us as input parameters for the creation of computational modeling and numerical analysis. Model of structure for the computer simulation was created in two-dimensional field by linear triangular elements for both types of graphitic cast iron. The size of elements was determined based on sensitivity analysis. According to the real structure of cast iron with vermicular shape of graphite and cast iron with globular graphite will be created model from which will be performed numerical analysis of voltage-strain states by finite element method – FEM software system ADINA 8.8.0. This calculation program helps to solve a very difficult task and has the advantage that the generated model can reflect very well the actual geometry of the object.

Specific features of the electrical properties in partially graphitized porous biocarbons of beech wood

The electrical and galvanomagnetic properties of partially graphitized highly porous bioC(Ni) biocarbon matrices produced by pyrolysis (carbonization) of beech wood at temperatures Tcarb = 850–1600°C in the presence of a Ni-containing catalyst have been studied in comparison with their microstructural features. The temperature dependences of the resistivity, the magnetoresistance, and the Hall coefficient have been measured in the temperature range of 4.2–300 K in magnetic fields to 28 kOe. It has been shown that an additional graphite phase introduction into samples with Tcarb ≥ 1000°C results in an increase in the carrier mobility by a factor of 2–3, whereas the carrier (hole) concentration remains within ~1020 cm−3, as in biocarbons obtained without catalyst. An analysis of experimental data has demonstrated that the features of the conductivity and magnetoresistance of these samples are described by quantum corrections related to their structural features, i.e., the formation of a globular graphite phase of nano- and submicrometer sizes in the amorphous matrix. The quantum corrections to the conductivity decrease with increasing carbonization temperature, which indicates an increase in the degree of structure ordering and is in good agreement with microstructural data.

Microdistribution of silicon in economically alloyed high-strength cast iron

The microdistribution of silicon in high-strength cast iron with globular graphite is considered. The influence of silicon microsegregation in the cast iron on its structure is analyzed.

Tribological Research of Properties of Heat – Treated Cast Irons with Globular Graphite

The contribution deals with the evaluation of tribological properties of materials: isothermally heat-treated cast iron ADI, heat-treated cast iron with globular graphite HTDI with sorbitic structure of the basic metal matrix and heat-treated steel C45. The aim of the research is to gain another knowledge for the application of materials in the condition where the loss of mechanical energy and the loss of material caused by parts wear are being appeared.

Microstructure, elastic and inelastic properties of partially graphitized biomorphic carbons

The microstructural characteristics and amplitude dependences of the Young’s modulus E and internal friction (logarithmic decrement δ) of biocarbon matrices prepared by beech wood carbonization at temperatures T carb = 850–1600°C in the presence of a nickel-containing catalyst have been studied. Using X-ray diffraction and electron microscopy, it has been shown that the use of a nickel catalyst during carbonization results in a partial graphitization of biocarbons at T carb ≥ 1000°C: the graphite phase is formed as 50- to 100-nm globules at T carb = 1000°C and as 0.5- to 3.0-μm globules at T carb = 1600°C. It has been found that the measured dependences E(T carb) and δ(T carb) contain three characteristic ranges of variations in the Young’s modulus and logarithmic decrement with a change in the carbonization temperature: E increases and δ decreases in the ranges T carb < 1000°C and T carb > 1300°C; in the range 1000 < T carb < 1300°C, E sharply decreases and δ increases. The observed behavior of E(T carb) and δ(T carb) for biocarbons carbonized in the presence of nickel correlates with the evolution of their microstructure. The largest values of E are obtained for samples with T carb = 1000 and 1600°C. However, the samples with T carb = 1600°C exhibit a higher susceptibility to microplasticity due to the presence of a globular graphite phase that is significantly larger in size and total volume.

Globular Graphite: Structure, Composition

The structure and elemental composition of graphite inclusions uncovered on high-strength cast iron by etching are studied. The chemical composition at various points and regions of graphite inclusions is determined. It is shown that the globular graphite is a unique lamellar-spiral system of micro- and nanoformations.

Use of Eddy-Current Method for Determining the Thickness of Induction-Hardened Layer in Cast Iron

Cast iron with globular graphite is studied after surface induction hardening. Hardness profiles of iron bars are plotted for determining the thickness of the hardened layer. Relations between the thickness of the hardened layer and the output voltage are obtained by the method of dual frequency (induced voltage and normalized impedance) for checking the applicability of the eddy current method. The correlation coefficient and the error of the evaluation of the thickness of the hardened layer are determined with the help of the relations obtained.

Influence of heat treatment on the phase composition and properties of high-strength cast iron

The phase composition, structure, and properties of high-strength cast iron are investigated as a function of the heat treatment. The influence of heat treatment on the wear of bainitic iron with globular graphite is also considered, in comparison with steel for the production of cast plowshares.

Special features of the internal structure of globular graphite in high-strength cast iron

Metallographic and microscopic x-ray spectrum analyses are used to study the special features of microstructure of pearlite-ferrite high-strength cast iron with globular graphite. It is shown that globular graphite has a polycrystalline structure and bears ferrite over boundaries of pyramidal crystals.

Bainitic high-strength cast iron with globular graphite

Special features of formation of bainitic structures in grayed cast irons are considered. The influence of the graphite phase and of the special features of chemical composition of the iron on the intermediate transformation in high-carbon alloys is allowed for. The range of application of high-strength cast irons with bainitic structure is determined. The paper is the last and unfinished work of G. I. Silman completed by his disciples as a tribute to their teacher.

Suitability of technical materials for machinery subsoilers for soil tillage

Agricultural soil processing belongs to the basic elements in the process of crop production. Currently classic tillage method is decreasing and the only trend has stated as a shallow plowing. Suitable post harvest soil tillage greatly affects yields in the next cycle. The aim of the study is the analysis of abrasive wear of selected construction materials and their subsequent use for DXRV-HD cultivator. The performed tests are focused on monitoring the mechanical properties of the materials and their use for variable cutting tip of cultivator body. Tested materials are divided into four categories. These materials include tool steel (19436), carbon steel (12050), cast iron with globular graphite and welding material supplied as a functional complex on low carbon steel by the Abraweld company. These materials are tested together with the original part of share cultivator. The present experiment is focused on metallorgraphic, mechanical and abrasive analysis. Structural component of the material is identified by metallographic photos and then compared with the impact strength tested on Charpy hammer. Followed the abrasion resistance according to CSN 01 5084 and the total evaluation of the tested samples are done.

Effect of hot plastic deformation on microstructural changes in cast iron with globular graphite

The effect of hot plastic deformation on the transformation of the primary (cast) microstructure of ductile cast iron with globular graphite (ductile cast iron) has been investigated. The results of metallographic (with the use of light and scanning electron microscopes) and electron microprobe analyses of experimental cast iron samples in the cast and deformed states have been discussed. It has been shown that an increase in the degree of plastic deformation from 20 to 80% brings significant microstructural changes in both the pearlitic-ferritic matrix and graphite inclusions of cast iron.

Austenite-Carbide Layering in Cast Irons and Steels

The possibilities and special features of formation of two-phase austenite-carbide structure in decomposition of supersaturated austenite are studied. The effect of alloying is considered for manganese steels, cast irons, and chilled nickel-molybdenum high-strength cast iron with globular graphite.

Effect of process features of pressure treatment on the microstructure and quality of parts of pipeline fittings from high-strength cast iron

Methods of form changing of parts from high-strength cast iron with globular graphite by plastic deformation aimed at widening the possibilities of forming the required structure and properties in the metal and the range of its application are considered. Processes for obtaining semiproducts from high-strength cast iron with the help of form-changing and separating operations are described. Results of analysis of the microstructure and hardness of the initial preforms and of the semiproducts obtained are presented.

A study of the structure and properties of high-strength bainite-carbide cast iron with globular graphite

The structure and mechanical properties of two high-strength bainitic cast irons with carbon equivalent close to the eutectic one are studied. Additional alloying of one of the metals with chromium is used to obtain a bainite-carbide structure. The effect of the parameters of bainitic hardening on the hardness, impact toughness, and wear resistance of the metals is studied.

Wear resistance of economically alloyed high-strength iron with globular graphite after casting in metallic molds

The excellent tribological properties of high-strength bainitic iron obtained by casting in metallic molds are confirmed by testing. The iron, alloyed with 1.0% Ni and 0.5% Cu, contains globular graphite.

Simulation of crystallization process of iron with globular graphite

Special features of distribution of graphite inclusions in cast iron with globular graphite (IGG) are studied. The method of fractal analysis of images is used for determining the regular features of the distribution of eutectic cells during crystallization of iron. The dependences obtained are used for developing a fractal model of cluster crystallization of IGG.

Cast-iron blast-furnace cooling plates with domestically-manufactured globular graphite

The ZSMK Casting Shop has developed an environmentally safe process for fabrication of cooling plates from high-strength cast iron, and has cast several test samples. VCh50 cast iron (GOST 7293-85) with globular graphite, which is used to ensure that a ferritic base metal forms in the relatively large castings required for the cooling plates; a ferritic base metal is the most stable at high temperature, prevents cast iron “growth,” and prevents the parts from becoming warped in use.

Development, Fabrication, and Comprehensive Tests of a Transport-Packaging Set with a Shell Made of High-Strength Cast Iron with Globular Graphite for Transportation of Spent Irradiated Fuel Assemblies

The design of a transport-packaging set equipped with a TUK-128 (TUK-128/1) container intended for transporting spent nuclear fuel from research reactors is described. The radiation safety, tightness, strength, and thermal stability of the transport-packaging set are considered. Results from emergency, shock, and fire tests of the container’s full-scale model are presented.