NONDESTRUCTIVE TESTING OF METAL PARTS AGRICULTURAL MACHINERY BASED ON INDUCTION FREQUENCY SCAN SURFACE LAYER

Author(s):  
Lavrentyev A. ◽  
◽  
Shifrin V. ◽  
Rudenko N. ◽  
Sycheva M. ◽  
...  
Author(s):  
Anatoly Dudnikov ◽  
Igor Dudnikov ◽  
Oleksandr Gorbenko ◽  
Anton Kelemesh

The paper considers the issues of increasing the reliability of agricultural machinery through the use of reinforcing processing of recovered machine parts by plastic deformation, which provides an increase in the quality of their surface layer during recovery. The operational stability of the piston fingers and the upper heads of the connecting rods restored by vibration reinforcement on the engines working in the mechanized agricultural complex was carried out: tractor - agricultural machine - car. Studies have shown that the amount of wear of piston fingers restored by the vibration deformation method is 1.23 times smaller than the traditional method of recovery, which confirms the effectiveness of vibration technology. Technological processes of restoration of discs of diggers of beet harvesters, discs of coulters of grain planers, plow blades with use of vibrating vibrations of the processing tool are developed and put into production. The results of these developments showed an increase of 1.21 times the time of beet harvester harvesting with the diggers' wheels with the vibration-strengthened method; an increase in technical use factor of 1.07 times, compared to new 65G steel wheels. To improve the reliability of the PLN-5-35, PLN-3-35 plows, the technology of restoration of working bodies - blades is developed and introduced into production, which provides for increase of their durability and durability. The coefficient of technical use of the plow units with the blades restored by the developed technology is 1.01 times higher than that of the plow units with the new blades made of 65G steel. The wear rate of the toe, width and thickness of the blade are 1.51 respectively; 1.22 and 1.27 times less than the new 65G steel blades. The results of the study of vibrating reinforcing processing of working bodies of agricultural machinery help to increase their resource, which provides increased reliability of machines.


2017 ◽  
Vol 177 ◽  
pp. 562-567 ◽  
Author(s):  
Zuzana Stankovičová ◽  
Vladimír Dekýš ◽  
František Nový ◽  
Pavol Novák

2013 ◽  
Vol 750-752 ◽  
pp. 1963-1966 ◽  
Author(s):  
Jia Wu He ◽  
Shi Ning Ma ◽  
De Ma Ba

For solving fatigue failure of surface on the metal parts, the Surface Nanocrystallization technology by pre-forceing rolling was developed. The feature and operaing principle of equipment were introduced. A nanocrystalline surface layer was fabricated on deposited layer by using pre-forceing rolling technology (PFRT) .The microstructure of treated specimens was characterized by using scanning electron microscopy and transmission electron microscopy. Experimental evidence showed, The obvious plastic deformation layer was observed, the thickness of deformation layer is about 15μm. A nanocrystalline surface layer was found after PFRT treatment. The grain size of equiaxed nanocrystallites with random crystallographic orientations on the top surface layer was about 10nm. Experimental analysis indicated the coars crystal in the surface layer could be refined into nanocrystalline by using the pre-forceing rolling technology, attaining optimizing surface structure of metal parts.


Author(s):  
D. N. Braski ◽  
P. D. Goodell ◽  
J. V. Cathcart ◽  
R. H. Kane

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.


Author(s):  
W. H. Wu ◽  
R. M. Glaeser

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.


Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).


Author(s):  
V. N. Filimonenko ◽  
M. H. Richman ◽  
J. Gurland

The high temperatures and pressures that are found in a spark gap during electrical discharging lead to a sharp phase transition and structural transformation in the surface layer of cemented carbides containing WC and cobalt. By means of X-ray diffraction both W2C and a high-temperature monocarbide of tungsten (face-centered cubic) were detected after electro-erosion. The W2C forms as a result of the peritectic reaction, WC → W2C+C. The existence and amount of the phases depend on both the energy of the electro-spark discharge and the cobalt content. In the case of a low-energy discharge (i.e. C=0.01μF, V = 300v), WC(f.c.c.) is generally formed in the surface layer. However, at high energies, (e.g. C=30μF, V = 300v), W2C is formed at the surface in preference to the monocarbide. The phase transformations in the surface layer are retarded by the presence of larger percentages of cobalt.Metallographic examination of the electro-eroded surfaces of cemented carbides was carried out on samples with 5-30% cobalt content. The specimens were first metallographically polished using diamond paste and standard procedures and then subjected to various electrical discharges on a Servomet spark machining device. The samples were then repolished and etched in a 3% NH4OH electrolyte at -0.5 amp/cm2. Two stage plastic-carbon replicas were then made and shadowed with chromium at 27°.


Author(s):  
M. J. Carr ◽  
J. F. Shewbridge ◽  
T. O. Wilford

Strong solid state bonds are routinely produced between physical vapor deposited (PVD) silver coatings deposited on sputter cleaned surfaces of two dissimilar metal parts. The low temperature (200°C) and short time (10 min) used in the bonding cycle are advantageous from the standpoint of productivity and dimensional control. These conditions unfortunately produce no microstructural changes at or near the interface that are detectable by optical, SEM, or microprobe examination. Microstructural problems arising at these interfaces could therefore easily go undetected by these techniques. TEM analysis has not been previously applied to this problem because of the difficulty in specimen preparation. The purpose of this paper is to describe our technique for preparing specimens from solid state bonds and to present our initial observations of the microstructural details of such bonds.


Author(s):  
B. Van Meerbeek ◽  
L. J. Conn ◽  
E. S. Duke

Restoration of decayed teeth with tooth-colored materials that can be bonded to tooth tissue has been a highly desirable property in restorative dentistry for many years. Advantages of such an adhesive restorative technique over conventional techniques using non-adhesive metal-based restoratives include improved restoration retention with minimal sacrifice of sound tooth tissue for retention purposes, superior adaptation and sealing of the restoration margins in prevention of caries recurrence, improved stress distribution across the tooth-restoration interface throughout the whole tooth, and even reinforcement of weakened tooth structures. The dental adhesive technology is rapidly changing. An efficient resin bond to enamel has already long been achieved. Its bonding mechanism has been fully elucidated and has proven to be a durable and reliable clinical treatment. However, bonding to dentin represents a greater challenge. After the failures of a dentin acid-etch technique in imitation of the enamel phosphoric-acid-etch technique and a bonding procedure based on chemical adhesion, modern dentin adhesives are currently believed to bond to dentin by a micromechanical hybridization process. This process is developed by an initial demineralization of the dentin surface layer with acid etchants exposing a collagen fibril arrangement with interfibrillar microporosities that subsequently become impregnated by low-viscosity monomers. Although the development of such a hybridization process has well been documented in the literature, questions remain with respect to parameters of-primary importance to adhesive efficacy.


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