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Effect of Regular Shot Peening and Semi-Random Shot Peening Conditions on Selected Properties of the Surface Layer of Gray Cast Iron

Skoczylas Agnieszka, Zaleski Kazimierz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

284--295

EN

Both dispersed and concentrated shot peening can be an effective method for the finishing of machine components. This work investigates the effect of two different shot peening (SP) processes conducted with the same technological parameters on selected properties of the surface layer of gray cast iron EN-GJL 250. Specifically, regular shot peening (RSP) and semi-random shot peening (SRSP) were investigated in the study. The results demonstrated that the surface quality of EN-GJL 250 samples was higher after RSP than after SRSP. The analyzed surface roughness parameters were lower after RSP than after SRSP, with the exception of the Rvk parameter. As a result of RSP, the analyzed roughness parameters increased from 5% to 62% in relation to their values after pre-treatment. The lowest values of the surface roughness parameters were obtained after RSP conduced with the impact energy E = 100 mJ, the distance between the dimples x = 0.3 mm, and the diameter of the shot peening element d = 14.3 mm. Assessment of the 3D surface topography showed significant differences in the formation of machining traces depending on the employed surface treatment. In RSP, the traces were arranged in a uniform manner, with the assumed step, whereas in SRSP the shot peening traces had no set pattern of orientation. The application of RSP and SRSP caused an increase in surface microhardness. The maximum surface microhardness was 75 HV0.5 for RSP and 98 HV0.5 for SRSP. Residual stresses were higher after SRSP than after RSP. Compressive residual stresses were induced in both types of shot peening process.

2

The Effect of Vibratory Shot Peening on the Geometric Structure of the Surface of Elements Machined by Laser and Abrasive Water Jet Cutting

Skoczylas Agnieszka

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 5

1--11

EN

Elements machined by laser and abrasive water jet cutting sometimes require the use of a finishing treatment. One of the finishing methods for machined elements is vibratory shot peening (VSP). This paper presents the influence of VSP technological conditions on the surface topography and surface roughness (parameters Ra and Rsk) of aluminium alloy AW-7075 samples. Experiments were carried out according to the following plan: first, vibratory shot peening (VSP) was conducted using balls with a diameter d = 3 mm, 6 mm and 9 mm. Then, the surfaces of the samples after VSP (treated with 6 mm diameter balls) were subjected to re-vibratory shot peening (RVSP). As a result of vibratory shot peening, the Ra parameter of the specimens after laser cutting decreased by 71% to 91%, while for the AWJ-treated elements it decreased by 56% to 85%. The additional operation decreased the Ra parameter in the entry zone by 4% to 6% for the samples after laser cutting and by 5% to 7% for the samples after AWJ, when compared to the Ra value after single vibratory shot peening conducted using balls with d=6 mm. After VSP and RVSP, the surface topography of the samples changed. Vibratory shot peening led to the creation of "striations" on the shot-peened surface that could not be completely removed. The re-vibratory shot peening operation (for specific conditions) had a positive effect on the geometric structure of the surface of the elements after cutting. Both VSP and RVSP caused reduction in the analysed 3D surface roughness parameters.

3

Vibratory Shot Peening of Elements Cut with Abrasive Water Jet

Skoczylas Agnieszka

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 2

39--49

EN

The paper presents the effect of technological parameters of vibratory shot peening on the roughness and microhardness of the surface layer of shot peened objects. Moreover, the surface topography results from vibratory shot peening was analyzed. In the experiment, samples made of 1.4301 stainless steel were used, which were cut by abrasive water jet (AWJ). The geometrical structure of the surface after vibratory shot peening was changed. The surface roughness was obtained in the range of Rsk = -0.600 ÷ -1.115 and Sa = 3.01 ÷ 6.53 μm, The value of microhardness ΔHV, near to the surface, is from 36 HV0.05 to 100 HV0.05. The changes in microhardness reach on the depth gh = 100 μm. An analysis of variance ANOVA for the investigated dependent variables was performed. The Tukey's test was used to checked the influence of the independent variable on the dependent variable. The aim to obtain favorable properties of the surface layer of elements after abrasive water jet cutting, it is recommended to use a vibratory shot peening time of approx. 6 minutes and balls of diameter d = 6 mm.

4

Influence of Centrifugal Shot Peening Parameters on the Impact Force and Surface Roughness of EN-AW 2024 Aluminum Alloy Elements

Skoczylas Agnieszka

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 1

71--78

EN

This article presents the results of experimental studies on the influence of centrifugal shot peening parameters on the impact force Fu occurring during the machining of the EN – AW 2024 aluminum alloy. The surface roughness parameters Ra, Rt, Rpk, Rvk and surface topography were also analyzed. Centrifugal shot peening was carried out on the FV-580a vertical machining center using a centrifugal shot peening head. Variable parameters of the centrifugal shot peening were: tangential speed vg and infeed g. On the basis of the results obtained, it was found that the increase the tangential speed vg and the infeed g causes an increase of the impact force. After centrifugal shot peening, numerous micro-cavities were formed on the surface of the EN-AW 2024 aluminum alloy samples, which may can accumulate lubricants in their space. During centrifugal shot peening, low values impact force Fu were obtained, which confirms the legitimacy of using this method as a finishing machining of elements with low stiffness.

5

The influence of vibratory shot peening on the selected properties of the surface layer elements made of cast iron

Zaleski Kazimierz, Skoczylas Agnieszka

Mechanik

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2019

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R. 92, nr 11

739--741

EN

The results of experimental investigations influence of vibratory shot peening on surface roughness and residual stress of spheroidal graphite cast iron objects were presented. The surfaces before vibratory shot peening were milled using different feed. After vibratory shot peening surface roughness Ra = 0.7÷0.9 μm was obtained and in surface layer compressive residual stress, with the maximum (absolute) value from 170 MPa to 330 MPa at a depth 0.4÷0.7 mm have been formed. For accepted vibratory shot peening condition it was recommended to use time of about 8 minutes.

PL

Przedstawiono wyniki badania wpływu czasu nagniatania wibracyjnego elementów z żeliwa sferoidalnego na chropowatość powierzchni i rozkład naprężeń własnych w warstwie wierzchniej nagniatanych przedmiotów. Powierzchnie przewidziane do nagniatania frezowano z posuwem o różnej wartości. W wyniku nagniatania uzyskano chropowatość powierzchni w granicach Ra = 0,7÷0,9 μm, a w warstwie wierzchniej ukształtowano ściskające naprężenia własne o maksymalnej (bezwzględnej) wartości od 170 MPa do 330 MPa na głębokości 0,4÷0,7 mm. Dla przyjętych warunków nagniatania zalecono stosowanie czasu nagniatania ok. 8 min.

6

Klasyfikacja szmerów oddechowych : badania pilotażowe

Stasiakiewicz Paweł, Dobrowolski Andrzej P., Olszewski Robert, Gałązka-Świderek Natalia, Targowski Tomasz, Skoczylas Agnieszka, Majka Katarzyna, Lejkowski Wojciech

Elektronika : konstrukcje, technologie, zastosowania

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2019

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Vol. 60, nr 2

4--12

PL

Układ oddechowy pacjenta jest początkowo diagnozowany przy zastosowaniu stetoskopu. Osłuchowa interpretacja zjawisk fizycznych jest skomplikowana i wymaga od lekarza doświadczenia oraz predyspozycji. W niniejszym artykule zaprezentowano system pomiarowy i oprogramowanie badawcze, a także proces generacji cech dystynktywnych szmerów oddechowych różnicujących przypadki chorobowe od zdrowych. Wybrane reprezentacje stanowią obiecującą podstawę do opracowania systemu klasyfikującego wspierającego proces diagnostyczny.

EN

Patients respiratory system is firstly diagnosed using stethoscope. Auscultatory interpretation of physical phenomena is complicated and requires from doctor experience and predisposition. This article presents measurement system and experimental software as well as distinctive feature generation process diversifying normal and pathological cases. Chosen representations of signal form a promising basis for classificatory system elaborating for supporting diagnostic process.

7

Studying the effect of finishing work on the geometric accuracy of the laser cut elements

Skoczylas Agnieszka

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 1

267--272

EN

The article presents the results of geometric accuracy studies of the C45 steel elements after laser cutting, and then subjected to finishing work. Burnishing and a combined machining and burnishing were applied as finishing works. Geometric accuracy studies of the elements after laser cutting and after finishing work were conducted in accordance with the PN – EN ISO 9013: 2017 – 04 standard. It has been noted that the finishing machining enables the improvement of geometric accuracy of the surface after laser cutting. Machining of elements after laser cutting allows for a reduction of the inclination index of the surface up to 42% with respect to the index value after laser cutting. Finishing milling makes it possible to reduce the surface inclination index more than twice. By performing burnishing of elements after laser cutting and finishing milling, no significant improvement of the element accuracy is obtained.

8

Geometric structure of the C45 steel surface after centrifugal burnishing and perpendicular shot peening

Skoczylas Agnieszka

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 2

20--28

EN

The paper presents the research results of roughness and surface topography of the C45 non-alloy steel after centrifugal burnishing and perpendicular peening. The assessment of the geometric structure of the tested steel surface included the parameters: amplitude: Ra, horizontal: RSm, height: Rz, Rp and Rv, and Abbott-Firestone curve: Rpk, Rk and Rvk. Perpendicular shot peening was performed on a special position, while centrifugal burnishing on a 3-axis milling centre XH712G. The variable parameters during shot peening included the impact energy Ez = 40 ÷ 220 mJ and the distance between traces xs = 0,15 ÷ 0,5 mm. The machining conditions of centrifugal burnishing were selected in such a way that the perpendicular component of the impact energy, longitudinal feed and transverse travel correspond to the variable parameters of perpendicular shot peening. The T800 RC 120 -140 device of the Hommel – Etamic company with software was used for measuring surface roughness and topography.