Wyniki wyszukiwania - Biblioteka Nauki

1

Badania udarności starzonych powłok polimerowych na podłożu stalowym

100%

Mayer P.

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2018

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tom Vol. 6, no. 1

1--5

PL

Obiekty techniczne podczas eksploatacji narażone są na destrukcyjne oddziaływanie środowiska, w którym się znajdują. Potrzeba rozwiązania tego problemu była główną przyczyną opracowania i stosowania powłok ochronnych, które wydłużą czas życia danych obiektów technicznych. W pracy przeprowadzono badania udarności wybranych powłok polimerowych, nałożonych na podłoże stalowe, które były poddane procesom starzenia. Badaniom poddano powłoki poliuretanowe, polimocznikowe i polimocznikowo-poliuretanowe, które narażone były na działanie promieniowania UV, środowiska kwaśnego oraz zmiennych temperatur. Po procesie starzenia powierzchnie powłok analizowano pod mikroskopem stereoskopowym oraz wyznaczono grubość powłok. W zależności od rodzaju powłoki oraz wypływu różnych czynników środowiskowych zaobserwowano zmiany w odporności na uderzenia.

EN

Technical objects, during operation, are exposed to the destructive impact of the environment in which they are located. The need to solve this problem was the main reason for the development and use of protective coatings, which will extend the lifetime of given technical facilities. The impact tests of selected polymer coatings applied to the steel substrate, which underwent aging processes, were performed in the work. Before applying the coatings, the steel substrate was subjected to abrasive blasting using as an abrasive an electrocorund with grain granulation F30. The roughness was measured on the profilometer by the contact method, determining the arithmetic mean deviation of the roughness profile - Ra and the roughness height by 10 points - Rz. Polyurethane, polyurea and polyurea-polyurethane coatings were subjected to tests, which were exposed to UV radiation, acidic environment and variable temperatures. Biresin® U1305 and Almacoat Floor SL polyurethane coatings, after mixing the ingredients in the right proportions, were applied by hand using a brush. The Almacoat Protect C coating, in accordance with the manufacturer's recommendations, was sprayed with a pneumatic gun. Accelerated aging using UV radiation was carried out for 3 weeks. The samples were placed in a chamber equipped with two T8 fluorescent lamps with a capacity of 18 W and two T8 fluorescent lamps with a power of 36 W, which emitted radiation from the UV-A range with a wavelength of 350 ÷ 400 nm. Aging of coatings in a 5% NaCl solution also took place over a period of 21 days. The samples were completely immersed in the solution and stored at room temperature. On the other hand, aging at variable temperatures consisted of subjecting the coatings to alternating high (+ 60 ° C) and low (-18 ° C) temperatures for 3 cycles, one cycle being 5 changes at 1 hour at low and high temperatures. After the aging process, the coating surfaces were observed under a stereoscopic microscope and the coating thickness was determined. Depending on the type of coating and the outflow of various environmental factors, changes in impact resistance were observed. Among the coatings tested, the highest impact strength was obtained for polyurea-polyurethane coatings (Protect C). Analyzing the effect of individual factors, UV radiation had the least impact on the deterioration of the impact strength of coatings, although the changes in appearance were significant. However, the aging of polyurethane and polyurea-polyurethane coatings in the NaCl solution reduces the impact resistance twice.

2

Weryfikacja młotów udarnościowych w świetle wymagań normy ASTM E23 i procedury NIST

84%

Stankiewicz M. , Cęckiewicz S.

Dozór Techniczny

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2001

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tom z. 5

111--113

3

Possibilities of neural networks using in the design, simulation and verification of the controlled gas nitriding process

84%

Michalski J. , Mruk R. , Wach P. , Burdyński K.

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tom Vol. 38, nr 4

177--182

EN

The article presents the possibility of neural networks application to design and simulate the growth kinetics of class 1 nitrided layers in steel 32CDV13 and 42CrMo4 (40HM), using data obtained from analytical models. The study analyses unidirectional multilayer neural networks with one hidden layer, with approximation properties. The algorithm developed takes into account the average thickness of the layer of iron nitride. This parameter is most frequently used for the classification of nitrided layers, especially for anticorrosion layers. As a result of research and discussion stated: the neural networks with approximating properties used allowed to build models, well-fitted to the data obtained using analytical models, taught structures of neural networks can be used in systems estimating the results of the nitriding process. The duration of the first stage of the process and the value of the potential in the second degree determine the thickness of the iron nitride layer obtained after the nitriding process. The value of the potential in the second stage also determines the intensity of limiting the thickness of the iron nitride layer. Nitriding decreases the impact strength of steel regardless of the thickness of the subsurface iron nitride layer. The iron nitride layer on the steel increases its resistance to frictional wear. Its resistance to friction wear increases with the increase of the thickness of this layer.

PL

Celem pracy była ocena możliwości wykorzystania sieci neuronowych do projektowania i symulacji kinetyki wzrostu warstw azotowanych na stalli 32CDV13 i 42CrMo4 (40HM), wykorzystując dane uzyskane z modeli analitycznych. W części weryfikacji eksperymentalnej, określenie udarności i odporności na zużycie przez tarcie tych stali po procesie regulowanego azotowania gazowego.