A review on analysis of ferrocement panels

Ferrocement is a highly versatile form of reinforced concrete made up of wire mesh, sand, water, and cement, which possesses unique qualities of strength and serviceability. It displays a series of advantages compared to reinforced concrete. Now a days ferrocement is widely used in engineering application due to high performance regards to the resistance to extension, resistance to impact, ductility. Numerous studies were conducted to understand the behaviour of ferrocement panels. This paper presents the review of studies conducted about the behaviour of ferrocement panel under static, dynamic, cyclic loading. Keywords- Ferrocement, cyclic loading, flexural behaviour, precast ferrocement wall, dynamic analysis, static analysis

Fractographic Study of the Mechanism of Destruction of the Nitrocarburized Layer

In this paper we investigate the nature of the impact fracture of steels 20 and 20Cr specimens in the nitrocarburized layer and in the core. The object of the study were the samples after thermocycling and isothermal nitrocarburizing. As the results showed, the greatest increase in impact ductility is achieved in five cycles of nitrocarburizing. It is shown that the destruction of the hardened layer and the steel core after the isothermal process is quasirectangular in nature. The presence of the diffusion layer treated by modes of thermocycling nitrocarburizing, areas of ductile fracture and quasi-cleavage in the fracture indicates greater intensity of the process of destruction in comparison with the isothermal process, in which areas of intergranular fracture are present and ductile fracture elements are not present in the fracture. Thus, the fractographic study revealed some features of the mechanism of steel destruction after chemical-thermal nitrocarburizing in comparison with the isothermal process. During thermal cycling of steels, a large amount of the ductile component is observed in the fracture. As the results showed, the greatest increase in impact ductility is achieved in five cycles. In steel 20Cr, the impact ductility increases by 2 times, and in steel 20 by 2.6 times. Increasing the number of cycles to 9 leads to a significant reduction in impact ductility. So in steel 20Cr after chemical-thermal nitrocarburizing, the impact ductility values become less than after classical processing. A further increase in the number of cycles leads to an even greater decrease in the impact ductility values.

Experiment on Doping Rare Earth Diamond Tools Matrix Composites with Fe Replacing Co

This paper makes the experimental experiment on adding rare earth elements cerium doped in diamond matrix composites. Based on the doping of rare earth in metal powders including tungsten carbide, iron and nickel, the cobalt in diamond matrix is entirely with iron and the process route of rare earth doping is indicated. The performance of matrix composites with rare earth elements and free of rare earth elements is measured and the results obtained show that the flexural strength, the hardness and the impact ductility of matrix composites with rare earth elements are improved and the flexural strength increases by 10~62% over that of the composites free of rare earth elements, and the impact ductility by about 5% correspondently. We have successfully studied out the rare-earth diamond tool matrix composites replacing Co with Fe, bearing good practical service performance and low price, and have made corresponding diamond bit.

Experimental Investigation on Impact Ductility of Polymer-Modified Concrete Subjected to Falling Weight Loading

The impact ductility of plain concrete and polymer-modified concrete with different p-c (polymer-cement) ratio were measured by bend-impact method. The impact-resistance of plain concrete and polymer-modified concrete were contrasted. The modified mechanism of polymer-modified concrete was analyzed. The results indicate that the impact ductility of concrete are increased with contents of polymer firstly and then reduced and the best p-c ratio is 15%. The test results also indicate that the concrete performance are modified by polymer, which prevent crack developing in microcosmic and improve impact ductility in macroscopic.

Microstructure and Properties of Dissimilar Metals Welded Joint of New Tamping Tine Steel for Railways Maintenance

The microstructure and mechanical properties of welded joint between 20SiMn3NiA and 40CrNiMo were studied by carbon-dioxide arc welding. According to the principle of low strength matching of dissimilar metals weld, the strength of the welded joint is 60% of that of 20SiMn3NiA, and the impact toughness reaches 60% of parent metal’s toughness. Also the impact ductility is high enough to meet the applications of divided structure tamping tine when the strength of welded joint is properly lower than that of 20SiMn3NiA. Furthermore the performances of fusion zone are worse than welded joint and heat-affected zone for martensitic brittle layer was formed during the welding of 20SiMn3NiA and 40CrNiMo.

Diamond Tools Matrix Composites of Co Replaced by Fe with Doping Rare Earth

The experiment on adding rare earth elements doped in diamond matrix composites is made. Based on the doping of rare earth in metal powders including tungsten carbide, iron and nickel, Co is entirely replaced by Fe with rare earth in diamond matrix composites, and the process route of rare earth doping is indicated. The related performance of is measured, and the results obtained show that the bending strength, the hardness and the impact ductility of Fe matrix composites with rare earth are improved. The practical service performance of Fe matrix composites with rare earth has reached up to the practical service performance of Co matrix, and bearing good practical service performance, low price, have made corresponding diamond tools.

Study on Microwave Curing Behavior and Performance of Epoxy/Versamid 125

The curing rate of epoxy/Versamid 125 (V125) by heating curing, room-temperature curing and microwave curing was compared. It is founded that applying microwave technology could effectively improve the curing rate and the curing time is only 3-4minutes. 140W microwave could cure the epoxy system in good condition, but 280W and 420W were easy to make the materials coking. The impact of diluent on mechnical properties of curing product were studied and it is showed that the impact strength increases and the impact ductility will be improved with the content of diluent increases, while the compressing strength, bending strength and tensile strength decrease.

GTA Welding of Copper Thick Plates by Using ERCuTi Welding Materials

The new welding material – ERCuTi alloys filler metals were developed specially for gas tungsten arc welding (GTAW) of copper. The hot cracking in welding copper is inhibited completely as the addition of de-oxidant element Ti in copper welding material. The degree of addition of Ti (2-4wt%) is critical when the susceptibility of cracking is to be suppressed. If the level is allowed to exceed 4wt%, more low-melting point eutectics (β-TiCu4and TiCu2) will be formed in the welds, and cracking susceptibility will be increased again. Results of mechanical properties tests show that although adding Ti increases the hardness and strength of the weld compared to the base metal, the impact ductility and the plastic properties are not decreased significantly.

Microstructure and Properties and Wear Resistant of Carbide Free Bainitic Casting Steel

The microstructure and properties and wear resistant of carbide free bainitic casting steel were studied by using of OM, TEM, XRD, impact test and abrasion test. The results showed that after normalizing at 1080°C and tempering at low temperature the microstructures consisted of bainitic ferrite, remaining austenite and no carbides with combination properties of strength and toughness. After tempering at 250°C the tensile strength was 1667MPa, Rockwell hardness HRC49 and impact ductility AKU 36J, respectively. This new casting steel by normalizing at 1080°Cand tempering at 200°C had better wear resistance than that of high manganese steel under the same test conditions, moreover the reason was analyzed.