Mechanical Properties Of Gray Iron Research Articles

Effect of Ultrasonic Treatment on Microstructure and Properties of Gray Cast Iron

The effect of ultrasonic treatment on the microstructure and properties of gray cast iron was studied. The samples were analyzed by metallographic microscope, scanning electron microscope, Brinell hardness tester, electronic universal testing machine, etc. The results showed that ultrasonic treatment could improve the pearlite content in the microstructure. After ultrasonic treatment, the tensile strength of gray cast iron can be improved to 266 MPa, which is 11.60% higher than that of the samples without ultrasonic treatment. Ultrasonic treatment can refine the size of graphite, which can reduce the stress concentration. In addition, the pearlite lamellar spacing can also be reduced, which is the main reason for improving the mechanical properties of gray iron.

Study of the effect of differentiated cooling modes on the structure and mechanical properties of gray cast iron

The effect of the differential cooling regime on the structure and mechanical properties of gray iron castings is investigated. A technical solution has been developed for the differentiated change in the cooling rate of cast iron castings. An increase in the cooling rate during dendritic crystallization was achieved by blowing the mold with compressed air. To slow down the cooling rate in the interval of eutectic transformation, an exothermic carbon-containing additive, fuel oil M-100, was used. It is shown that the use of controlled cooling can significantly increase the tensile strength of cast iron without introducing additional alloying elements into the composition of cast iron.

Effect of alloying elements W, Ti, Sn on microstructure and mechanical properties of gray iron 220

Experiments were carried out to observe the variation in microstructure and mechanical properties of gray cast iron by adding pearlite promoting alloying elements such as Ti, Sn and W. Results show that adding Sn, Ti, and W with different concentrations improve the microstructure, Brinell hardness and tensile strength of gray cast iron. With the increase of alloying element concentration, the average graphite length and graphite content increase linearly. At the same time, average cell size and the maximum graphite length also decrease linearly. Brinell hardness and tensile strength of gray cast iron also increase with an increase in alloying elements contents, and attain the maximum when Ti = 0.561%, Sn = 0.561% and W = 0.945%. However, at higher concentrations of Ti = 0.810%, Sn = 0.631% and W = 1.351%, the tensile strength decreases from 333 MPa to 297 MPa and the Brinell hardness decreases from 248 HB to 225 HB. The decrease in tensile strength and Brinell hardness at the higher concentration level is attributed to the formation of coarse and thick graphite flakes.

Relationship between Graphite Flake Sizes and the Mechanical Properties of Grey Iron

Cast Irons are important engineering materials which possess a wide range of attractive properties. Their properties are significantly dependent on the microstructure of the cast, cast iron components. A way of controlling the microstructure of cast iron is through the control of cooling rates during solidification. To control cooling rate, the heat storage capacity of the mould is important. This paper presents the report of a study on the characteristic effects of graphite flake sizes on some mechanical properties of grey cast iron. Six mould materials with heat storage capacities ranging from 1.52 kJ.m-2.K-1.s-1/2 to 2.16 kJ.m-2.K-1.s-1/2 were prepared and used to cast some grey cast iron samples whose microstructures were observed by optical microscopy. Mechanical properties of the grey iron were evaluated. The results show that the properties increased with the heat storage capacity of the mould. Also, the microstructures show a dependence on heat storage capacity of the mould.

Characterization of Graphite Flakes in Grey Iron Microstructure

Cast irons are important engineering materials which possess a wide range of attractive properties. Their properties are significantly dependent on the microstructure of the cast and cast iron components. A way of controlling the microstructure of cast iron is through the control of cooling rates during solidification. To control cooling rate, the heat storage capacity (HSC) of the mould is important. This paper presents the report of a study on the characteristic effects of graphite flake sizes on some mechanical properties of grey cast iron. Six mould materials with HSCs ranging from 1.52 to 2.16 kJ m−2 K−1 s−1/2 were prepared and used to cast some grey cast iron samples whose microstructures were observed by optical microscopy. Mechanical properties of the grey iron were evaluated. The results show that the properties increased with the HSC of the mould. In addition, the microstructures show a dependence on HSC of the mould.

Effect of Hot Compression on Mechanical Properties of Gray Iron

Gray iron was hot-compressed on a Gleeble 3500 machine. The effect of hot compression on mechanical properties of gray iron was studied. The result shows that gray iron with the sandwich structure of graphite and ferrite matrix is prepared after more than 45% reduction of hot compression. The mechanical properties of 80% hot-compressed gray iron are significantly enhanced: tensile strength from 117MPa to 249MPa, and total elongation from 0 to 5.2%. The tensile fracture surface presents ductility characters after more than 45% reduction of hot deformation. The increase of the strength and ductility of the hot-compressed gray iron is caused by delamination toughening.

The effect of ausferrite formation on the mechanical properties of gray iron

By controlling the composition, ASTM class 35 gray iron can be cast directly to produce a microstructure ranging from fully pearlitic to that containing 100% ausferrite. An increase in volume fraction of ausferrite resulted in a concomitant linear increase in key mechanical properties with the fully ausferritic gray iron producing the optimum combination of mechanical properties.

Reasons for the low accuracy of hardness measurements on gray iron

It is established that the mechanical properties of gray iron have a significant effect on the errors seen in measurements of its hardness. Parameters are found and evaluated to reduce the scatter of hardness.