Hardened Edges Effects On Wear Characteristics of Cultivator Sweeps Using Circular Soil Bin Test

Tillage tools are subject to friction and low-stress abrasive wear processes with the potential deterioration of the desired soil quality, loss of mechanical weed efficacy, and downtime for replacing worn tools. Limited experimental methods exist to quantify investigate the effect of wear-resistance coatings on shape parameters of soil-engaging tools. ASTM standard sand/rubber wheel abrasion and Pin-On-Disk tests are not able to simulate wear characteristics of complex shape of the tillage tools. Even though the tribology of tillage tools can be realistic from field tests, tillage wear tests under field conditions are expensive and often challenging to generate repeatable engineering data due to variable soil conditions in the field. A technique that simulated tillage wear of cultivator sweep in a circular soil bin filled with abrasive gravel medium and moisture condition was developed and applied to quantify the wear characteristics of cultivator sweeps with and without hard-faced edges. The hard-faced cultivator sweep had a cemented carbide chips applied to the bottom cutting edge and front tip sections of a standard cultivator sweep according to a proprietary CADENEdge welding process. The CADENEdge hard-faced sweeps showed improved wear performance 1.7 times and 3.5 times on mass and shape (sweep length and sweep wing cutting width) dimensions, respectively, compared with the un-hardened standard sweep. The results implied hard-faced cultivator sweep with cemented carbide chips provide potential in maintaining tillage productivity and the desired soil quality for seed-bed preparation.

ULTRASONIC EFFECT ON ELECTRIC SPARK FORMING AND DEVELOPMENT IN ELECTROACOUSTIC SPRAYING

Introduction. The electroacoustic application of wear-resistance coatings is studied. The work objective is to obtain a mathematical model of the ultrasonic effect on the formation and development of an electric spark occurring in the process of the electroacoustic sputtering.Materials and Methods. The effect of ultrasonic vibrations on the processes occurring during the formation and development of a spark discharge is analyzed; the equations of continuity, energy motion and transfer, with the ultrasonic field contribution are considered. Factors affecting the thermal conductivity and electrical conductivity of strongly ionized gas are studied. Research Results. When obtaining the model, it was assumed that the heat removal from the channel is carried out by a “clear emitter”. Then, for the channel region, a self-similar solution is made: pressure, temperature and density are constant over the cross-section, and velocity is proportional to the radius. A mathematical model that describes the processes occurring in the spark channel with the ultrasonic field energy effect is obtained.Discussion and Conclusions. On the basis of the developed model, it is specified that under the ultrasonic radiation effect, the radius and temperature of the spark channel increase, and conditions of the double ionization under high ultrasonic energy are created.

Wear-resisting properties of multilayer coated carbide blades under different technological conditions of turning of heat-resistant steel

Experimented results of wear-resisting properties of carbide blades with multilayer wear-resistance coatings, obtained by different processes: chemical vapor deposition and spraying by condensation from vapour (gas) phase while turning of corrosion –resistant heat-resistant steel 08Х18Н10Т are presented.

CRACK-FREE WEAR RESISTANCE COATINGS PRODUCED ON PURE TITANIUM AND Ti-6Al-4V BY LASER NITRIDING

Cracks-free wear resistance coatings are fabricated by laser surface nitriding pure titanium and Ti-6Al-4V in an open system. The titanium nitrides which are formed in situ in the top layers of the samples are undeveloped dendritic, and thus reduce the possibility of the crack formation in the coatings during laser processing. The test results show that the nitride layers have higher microhardness and more resistant to sliding wear compared to the as-received sample.

Characterization of Al2O3 and SiC Particles, Reinforced Al Powders, and Plasma Sprayed Wear Resistance Coatings

Aluminum coatings reinforced with either Al2O3 or SiC particles were deposited onto aluminum substrates and subjected to various tests. The coatings were made with mechanically alloyed powders via atmospheric plasma spraying (APS). Both types of coatings had uniformly distributed hard particles, porosities in the range of 4 to 5%, and bond strengths of around 20 MPa. The wear resistance of the SiC-reinforced coatings, however, was almost 35% higher than the coatings containing Al2O3. X-ray examination (XRD) showed that the Al2O3 particles undergo partial phase transformation during spraying, making them more prone to wear.