scholarly journals Hole accuracy increase at hole reaming in hard-to-machine parts

Author(s):  
Сергей Агапов ◽  
Sergey Agapov ◽  
Юрий Сидякин ◽  
Yuryi Sidyakin ◽  
Олег Корпелянский ◽  
...  

The investigation results of the tool geometry impact upon accuracy of holes worked in hard-to-machine parts at the ultrasonic oscillation introduction in a cutting area are shown. The processes of hole reaming in parts made of stainless steel and titanium alloys at ultrasonic oscillation application upon a tool are considered. Tool basic parameters defining the accuracy of holes obtained are defined. The regularities of the impact of face and back angles of reamer cutting ends, an angle of an intake cone and a tool spiral direction upon a hole smash are revealed.

2012 ◽  
Vol 433-440 ◽  
pp. 552-557 ◽  
Author(s):  
Gerhard Petuelli ◽  
Christoph Nentwig

In this paper results of manufacturing tests are described done in order to evaluate the performances of twist drills of diameter d = 1.2 mm and 1.4 mm respectively, if boring into stainless steel X90CrMoV18 (1.4112). Deep-hole drilling was realized thus, that the depth of the bore hole was greater than 10 times the diameter of the twist drill (L/d >10). In order to reduce the impact on the environment caused by the coolant, it was found that minimum quantity lubrication (MQL) can be applied. Hence, the ecology of the mass production of perforated discs for the food processing industry can be improved. The performance of the several small diameter twist drills was determined and evaluated by, firstly, their deep-hole drilling capability, e.g. assessed by the variation or even increase of cutting forces with increasing depth and travel, whether the forces exceed a critical level due to poor chip extraction. In addition, the suitability to use or rather implement the different small diameter twist drills for high-speed cutting (HSC) and finally the individual tool service life for each investigated twist drill. This research project has shown that the accomplishable performance and operating time are strongly dependent on tool cutting material and the tool geometry, especially the size of the chip flutes of a twist drill, as well as the individual coating of the cutting tools.


Author(s):  
Oleksandr Synenko ◽  
Kateryna Yarema ◽  
Yuliia Bezsmertna

The subject of the research is the approach to the possibility of using the Solow model to perform the regression analysis on the example of the Ukrainian economy model. The purpose of writing this article is to investigate the notion of regres- sion analysis, Solow’s economy model, algorithm for performing regression analy- sis on the example of Ukraine’s economy model. This model can be adapted for the economy of enterprises. Methodology. The research methodology is system-struc- tural and comparative analyzes (to study the structure of GDP); monograph (when studying methods of regression analysis on the example of the Ukrainian economy); economic analysis (when assessing the impact of factors on Ukraine’s GDP). The scientific novelty consists the features of the use of the Solow model on the ex- ample of Ukrainian economy are determined. An algorithm for calculating the basic parameters of a model using the Excel application package is disclosed. The main recommendations on the development of the national economy and economic growth through the use of macroeconomic instruments are given. Conclusions. The use of the Solow model enables forecasting and analysis. The results obtained re- vealed the problem of low resource return of capital as a resource, along with the means of macroeconomic regulation of the investment process, using which can improve the situation. A special place in these funds belongs to the accelerated depreciation and interest rate policies.


2020 ◽  
pp. 376-379
Author(s):  
S.A. Yakovlev ◽  
M.M. Zamal’dinov ◽  
A.A. Glushchenko ◽  
I.R. Salakhutdinov

The hardening methods of titanium alloys are analyzed. Effect of heating temperature on resistance of VT22 alloy structures strengthened by electromechanical processing is defined. Results of change in hardness of the strengthened structures depending on heating temperature are presented. Recommendations on the operational modes of machine parts made of alloy VT22 strengthened by electromechanical processing are provided.


Author(s):  
Apeksha D. Patil ◽  
Dhiraj B. Patil

Karaveera (Cerebra thevetia Linn.) is reported under Upavisha Dravya in classical ayurvedic pharmacopeias. It is observed that Shodhana (purification procedures) of the mool should be carried out before its internal administration. There are different Shodhana methods mentioned in Ayurveda. In this study Godugdha was used as media. The impact of Shodhana was evaluated by physico analytical study. It clearly proves physico analytical changes during Shodhana. Ashuddha Karaveera was taken on white clean cloth and they dumped in Pottali with Godugdha. Pottali was tied to middle of wooden rod dipped in Godugdha in stainless steel vessel and mild heat given to pottali in Dolayantra. Shuddha Karaveera was obtained and then washed with leuk warm water and dried. Ashuddha Karaveera contains toxin in it which was removed after Shodhana process. So that foreign matter, loss on drying was less in Shuddha Karaveera and due to Shodhan process with Godugdha total ash, acid insoluble ash was more than that of Ashuddha Karaveera.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 408
Author(s):  
Ewa Sjöqvist Persson ◽  
Sofia Brorson ◽  
Alec Mitchell ◽  
Pär G. Jönsson

This study focuses on the impact of solidification on the inclusion morphologies in different sizes of production-scale electro-slag remelting (ESR) and electro-slag remelting under a protected pressure-controlled atmosphere, (PESR), ingots, in a common martensitic stainless steel grade. The investigation has been carried out to increase the knowledge of the solidification and change in inclusion morphologies during ESR and PESR remelting. In order to optimize process routes for different steel grades, it is important to define the advantages of different processes. A comparison is made between an electrode, ESR, and PESR ingots with different production-scale ingot sizes, from 400 mm square to 1050 mm in diameter. The electrode and two of the smallest ingots are from the same electrode charge. The samples are taken from both the electrode, ingots, and rolled/forged material. The solidification structure, dendrite arm spacing, chemical analyzes, and inclusion number on ingots and/or forged/rolled material are studied. The results show that the larger the ingot and the further towards the center of the ingot, the larger inclusions are found. As long as an ingot solidifies with a columnar dendritic structure (DS), the increase in inclusion number and size with ingot diameter is approximately linear. However, at the ingot size (1050 mm in diameter in this study) when the center of the ingot converts to solidification in the equiaxial mode (EQ), the increase in number and size of the inclusions is much higher. The transition between a dendritic and an equiaxial solidification in the center of the ingots in this steel grade takes place in the region between the ingot diameters of 800 and 1050 mm.


Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1094
Author(s):  
M. A. Lakhdari ◽  
F. Krajcarz ◽  
J. D. Mithieux ◽  
H. P. Van Landeghem ◽  
M. Veron

The impact of microstructure evolution on mechanical properties in superduplex stainless steel UNS S32750 (EN 1.4410) was investigated. To this end, different thermomechanical treatments were carried out in order to obtain clearly distinct duplex microstructures. Optical microscopy and scanning electron microscopy, together with texture measurements, were used to characterize the morphology and the preferred orientations of ferrite and austenite in all microstructures. Additionally, the mechanical properties were assessed by tensile tests with digital image correlation. Phase morphology was not found to significantly affect the mechanical properties and neither were phase volume fractions within 13% of the 50/50 ratio. Austenite texture was the same combined Goss/Brass texture regardless of thermomechanical processing, while ferrite texture was mainly described by α-fiber orientations. Ferrite texture and average phase spacing were found to have a notable effect on mechanical properties. One of the original microstructures of superduplex stainless steel obtained here shows a strength improvement by the order of 120 MPa over the industrial material.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 773
Author(s):  
Y.H. Guo ◽  
Li Lin ◽  
Donghui Zhang ◽  
Lili Liu ◽  
M.K. Lei

Heat-affected zone (HAZ) of welding joints critical to the equipment safety service are commonly repeatedly welded in industries. Thus, the effects of repeated welding up to six times on the microstructure and mechanical properties of HAZ for AISI 304N austenitic stainless steel specimens were investigated by a Gleeble simulator. The temperature field of HAZ was measured by in situ thermocouples. The as-welded and one to five times repeated welding were assigned as-welded (AW) and repeated welding 1–5 times (RW1–RW5), respectively. The austenitic matrices with the δ-ferrite were observed in all specimens by the metallography. The δ-ferrite content was also determined using magnetic and metallography methods. The δ-ferrite had a lathy structure with a content of 0.69–3.13 vol.%. The austenitic grains were equiaxial with an average size of 41.4–47.3 μm. The ultimate tensile strength (UTS) and yield strength (YS) mainly depended on the δ-ferrite content; otherwise, the impact energy mainly depended on both the austenitic grain size and the δ-ferrite content. The UTS of the RW1–RW3 specimens was above 550 MPa following the American Society of Mechanical Engineers (ASME) standard. The impact energy of all specimens was higher than that in ASME standard at about 56 J. The repeated welding up to three times could still meet the requirements for strength and toughness of welding specifications.


Author(s):  
Ali Salehi ◽  
Armin Rahmatfam ◽  
Mohammad Zehsaz

The present study aimed to study ratcheting strains of corroded stainless steel 304LN elbow pipes subjected to internal pressure and cyclic bending moment. To this aim, spherical and cubical shapes corrosion are applied at two depths of 1 mm and 2 mm in the critical points of elbow pipe such as symmetry sites at intrados, extrados, and crown positions. Then, a Duplex 2205 stainless steel elbow pipe is considered as an alternative to studying the impact of the pipe materials, due to its high corrosion resistance and strength, toughness, and most importantly, the high fatigue strength and other mechanical properties than stainless steel 304LN. In order to perform numerical analyzes, the hardening coefficients of the materials were calculated. The results highlight a significant relationship between the destructive effects of corrosion and the depth and shape of corrosion, so that as corrosion increases, the resulting destructive effects increases as well, also, the ratcheting strains in cubic corrosions have a higher growth rate than spherical corrosions. In addition, the growth rate of the ratcheting strains in the hoop direction is much higher across the studied sample than the axial direction. The highest growth rate of hoop strain was observed at crown and the highest growth rate of axial strains occurred at intrados position. Altogether, Duplex 2205 material has a better performance than SS 304LN.


Author(s):  
S. Kuroda ◽  
T. Fukushima ◽  
T. Kodama ◽  
M. Sasaki

Abstract 316L stainless steel and Hastelloy C alloy powders were sprayed by an HVOF apparatus onto mild steel substrates. The microstructure, pore size distribution, composition and corrosion resistance of thus obtained coatings were evaluated experimentally. Corrosion resistance in sea-water was examined by monitoring the impedance and corrosion potential of samples immersed in artificial sea-water at 300 K over a period of more than 3 months and also by polarization measurement. It was found that the stainless coatings composed mainly of plastically deformed particles and some splats which were molten at the impact. By increasing the combustion pressure, the porosity as measured by mercury porosimeter could be reduced to below 1%. In comparison, Hastelloy C deposits sprayed under the standard condition were so dense that its porosity could not be measured by the porosimeter. The polarization curve and the results of impedance monitoring both exemplified that the Hastelloy C coatings possess much superior corrosion resistance to the stainless coatings in sea-water, which was attributed to the higher density and better adhesion of the Ni-base alloy coatings.


Author(s):  
S Giljean ◽  
M Bigerelle ◽  
K Anselme

This study aims to perform a multiscale analysis of abraded surfaces of 316L austenitic stainless steel and titanium alloys (TiAl6V4) grinded at different paper grades. The authors propose to answer the following question: For a given distribution of silicon carbide grains of the paper, what is the best roughness parameter and at which scale must it be evaluated better to discriminate the effect of the mechanical properties of the materials? Paper grades from 80 to 4000 were used under identical pressure and erosion time. It can be concluded that the values of the amplitude roughness parameters depend on the observation scale. It is outlined that the abrasion process is very reproducible. A statistical analysis is then proposed, first, to define a classification of the relevance of the roughness parameters for each grain size distribution, and second, to determine at which scale the mechanical properties of the bulk are more influenced for all paper grades. Finally, at relevant scales, the Abbott amplitude parameters roughness kernel (RK) is the best parameter to discriminate the paper grade effect. The mean distance between asperities (SM) is the preferred method for determining the wear effect on materials and the linear mean normalizing autocorrelation (AMNLN) is the preferred method for determining the interaction between paper grade and materials.


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