Wyniki wyszukiwania - BazTech

1

Tribological properties of hybrid aluminium matrix composites reinforced with boron carbide and ilmenite particles for brake rotor applications

Gupta Rahul, Nanda Tarun, Pandey O. P.

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 1

art. no. e47, 2023

EN

In the present study, stir casting process was employed to incorporate a blend mixture of ilmenite (FeTiO3) and boron carbide (B4C) particles in the matrix of LM13 base alloy. The study demonstrated the effect of individual reinforcement, weight percentage and mixing proportion on wear behaviour of LM13 alloy for brake rotor applications. Composite with 15 wt.% of reinforcement having 75% proportion of boron carbide (15BI-31 composite) shows change in silicon morphology to globular and highest refinement of silicon structure. Highest wear resistance, highest hardness, lowest coefficient of thermal expansion and lowest friction coefficient values were obtained for 15BI-31 composites. The addition of ilmenite particles enhances the properties of BI composites by making the strong interfacial bonding and enhancing the oxidation rate of sliding surface. However, the increase in dislocation density by boron carbide particles helps in enhancing the hardness of composites which contributes in providing the stability to mechanical mixed layer. The comparable wear property (17% higher wear rate), low processing cost and low material cost of 15BI-31 composite make it a suitable material for brake rotor applications. The predominant wear mechanism for composites was observed to be abrasive wear and delamination wear. However, the severity of wear mechanism changes as the applied load increases.

2

Infuence of heat treatment (routes) on the microstructure and mechanical properties of 300M ultra high strength steel

Kasana Shivraj Singh, Sharma Sandeep, Pandey O. P.

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 3

art. no. e126

EN

The study covered investigation of heat treatment (routes) effect on heat treatment of 300M ultra high strength steel to achieve the desired microstructure and the corresponding mechanical properties. 300M steel was prepared and subjected to diferent homogenization and forging processing. Structure-property relationship was established for both conventional and heat treatment route as well as isothermal and modifed route. Micrographs of 300M steels indicated that the isothermal heat treatment provided higher volume of retained austenite along with martensite and bainite. X-ray difraction (XRD) revealed that the dislocation density of isothermally heat-treated 300M steels was higher than the conventional steel. Isothermally heat-treated 300M samples have shown improved elongation and impact strength with the marginal loss of yield strength and ultimate tensile strength. Yield strength (1605 MPa), ultimate tensile strength (1890 MPa), impact strength (28 J), and percentage elongation (22%) of the isothermally heat-treated samples were comparable to the specifcations of the customer i.e., minimum yield strength 1480 MPa, ultimate tensile strength 1803 MPa, percentage elongation 7% and impact strength at −40 °C of 20 J, respectively. The SEM analysis of tensile and impact fractured surfaces revealed the large number of dimples which indicate the good ductility and toughness in the isothermally heat-treated samples.

3

Dry sliding wear characteristics of 0.13 wt. % carbon steel

Gupta V.K., Ray S., Pandey O.P.

Materials Science Poland

|

2008

|

Vol. 26, No. 3

617--631

EN

Wear characteristics of 0.13 wt. % plain carbon steel, heat treated under various conditions, were monitored on a standard pin-on-disk wear testing machine under the normal loads of 2.5, 4.5 and 5.5 kg and at a constant sliding velocity of 1 m/s. Weight loss of the specimen was measured at various time intervals to obtain wear rate. The variation in volume loss with sliding distance indicated the presence of run-in wear followed by steady state wear. The wear mechanism was found to be primarily oxidative in nature, which was confirmed by the analysis of worn surfaces and wear debris generated during sliding. Wear resistance was found to be dependent on the microstructure and morphology of the phases. The wear coefficients calculated for various heat-treated specimens revealed that the ferrite-coarse pearlite, ferrite-fine pearlite, ferrite-tempered martensite and ferrite martensite structures show the wear resistance in decreasing order.