scholarly journals Microstructure and hardness of Pyrowear 53 steel after low-pressure vacuum carburizing at 921°C

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Artur Wojtyczka ◽  
Bartosz Iżowski
Keyword(s):  
Surface Layer ◽  
Treatment Process ◽  
Low Pressure ◽  
Vacuum Carburizing

AbstractThe present paper studies and analyzes the low-pressure vacuum carburizing of Pyrowear 53 steel. The carburizing was performed at 921°C. The results after the completion of the treatment process are presented, i.e. microstructure of the surface layer and hardness. The results confirm that carburizing can be effectively used in hardening of the steel.

scholarly journals The Hybrid Process of Low-Pressure Carburizing and Metallization (Cr + LPC, Al + LPC) of 17CrNiMo7-6 and 10NiCrMo13-5 Steels

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 567
Author(s):  
Paulina Kowalczyk ◽  
Konrad Dybowski ◽  
Bartłomiej Januszewicz ◽  
Radomir Atraszkiewicz ◽  
Marcin Makówka
Keyword(s):  
Corrosion Resistance ◽  
Surface Layer ◽  
Physicochemical Properties ◽  
Surface Treatment ◽  
Retained Austenite ◽  
Treatment Process ◽  
Active Surface ◽  
Low Pressure ◽  
Low Alloy Steel ◽  
Chromium Plating

This paper presents the concept of modification of physicochemical properties of steels by simultaneous diffusion saturation with carbon and chromium or aluminum. The application of a hybrid surface treatment process consisting of a combination of aluminizing and low-pressure carburizing (Al + LPC) resulted in a reduction in the amount of retained austenite in the surface layer of the steel. While the use of chromium plating and low-pressure carburizing (Cr + LPC) induced an improvement in the corrosion resistance of the carburized steels. It is of particular importance in case of vacuum processes after the application of which the active surface corrodes easily, as well as in case of carburizing of low-alloy steel with nickel, where an increased content of retained austenite in the surface layer is found after carburizing.

The Modification of Carbon Included Polyethylene Surface by Plasma Treatment for Metallizing Using a Low Pressure RF Discharge Plasma

2005 ◽  
Vol 8 (1) ◽  
Author(s):  
Jeou-Long Lee ◽  
Chung-Ming Liu ◽  
Kuen Ting ◽  
Wei-Kung Cheng ◽  
Takayoshi Tsuchida ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Layer ◽  
Discharge Plasma ◽  
Treatment Time ◽  
Low Pressure ◽  
Rf Discharge ◽  
Nickel Layer ◽  
Good Adhesion ◽  
Polyethylene Surface

AbstractSurface modification of the carbon included polyethylene (semi-conductive PE) surface for metallizing using a low pressure RF discharge plasma has been carried out. The contact angle was used as a measure of the wettability of the PE surface. The roughness and the chemical bondings in PE surface layer were analized by DFM and XPS, respectively. Typical results show that the contact angle decreases from approximately 94° to below 10° after several minutes' treatment and recovers to a saturation value when it was put open to the air after treatment. The saturation value of the contact angle is smaller as the gas pressure for treatment is higher and the treatment time is longer but all are below approximately 60° which is still smaller than that of untreated. DFM and XPS results show that the surface roughness and the bondings C-O and C=O in the PE surface layer also increase with increasing the treatment time and seem to be responsible for improving the hydrophilic property of PE. After pretreatment process, nickel was coated on the PE sheet by electrodeposition method and a good adhesion between the nickel layer and the PE surface compared with that of untreated was obtained.

scholarly journals Mathematical Modeling of Carbon Flux Parameters for Low-Pressure Vacuum Carburizing with Medium-High Alloy Steel

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1075
Author(s):  
Haojie Wang ◽  
Jing Liu ◽  
Yong Tian ◽  
Zhaodong Wang ◽  
Xiaoxue An
Keyword(s):  
Carbon Concentration ◽  
Carbon Flux ◽  
Carbon Fluxes ◽  
Low Pressure ◽  
Process Conditions ◽  
Flux Method ◽  
Vacuum Carburizing ◽  
Initial Carbon ◽  
Vacuum Carburization ◽  
And Diffusion

Low-pressure vacuum carburizing adopts a pulse process mode to improve the carburizing efficiency and reduces gas and energy consumption. Carbon flux is the key to accurately control the time of strong infiltration and diffusion in each pulse. In order to obtain the carbon fluxes with various materials under diffident carburizing process conditions, an evenly segmented carbon flux method is proposed. A systematic study with each model using different materials (12Cr2Ni4A, 16Cr3NiWMoVNbE, and 18Cr2Ni4WA represent different initial carbon concentrations and different alloy compositions), carburizing temperatures, and carburizing pressures to determine the effect of these conditions on carbon flux is conducted. Compared with traditional segmented carbon flux method, an evenly segmented carbon flux method can predict the actual carbon flux more precisely and effectively in order to finely control the pulse carburization process. The paper also indicates that carbon fluxes increase with the increase of pressure. The optimal carburization pressure for low-pressure vacuum carburization is 300 Pa. Raising the carburization temperature to 980 °C instead of 920 °C can increase effective carbon flux by more than 30%. Among the material compositions, alloy content has the biggest impact over the carbon, initial carbon concentration the second, and saturated carbon concentration the third biggest impact.

Process Temperature Effect on Surface Layer of Vacuum Carburized Low-Alloy Steel Gears

2015 ◽  
Vol 227 ◽  
pp. 425-428 ◽  
Author(s):  
Kamil Dychtoń ◽  
Paweł Rokicki ◽  
Andrzej Nowotnik ◽  
Marcin Drajewicz ◽  
Jan Sieniawski
Keyword(s):  
Surface Layer ◽  
Chemical Treatment ◽  
Power Transmission ◽  
High Strength ◽  
Aircraft Engine ◽  
Carbon Diffusion ◽  
Process Temperature ◽  
Process Time ◽  
Vacuum Carburizing ◽  
Carburized Layer

Gears, due to their complex shape, carried load and required accuracy are ones of most complex aircraft engine parts. Single tooth damage usually breaks the power transmission and causes failure of the entire gear system. Adequate sustainability and guarantees of transmission is therefore a condition for secure operation of whole device. Particularly high requirements for reliability are put to transmissions used in the aerospace industry. Due to the loads which are transmitted through the gears, the materials used by the manufacturer must have not only high strength but also show the abrasion resistance of the surface layer and the ductility of the core. Thermo-chemical treatment of industrial gears is a fundamental process, which gives them adequate mechanical properties regarding loads they carry and the surface conditions of work. The most promising method in the discussed field is vacuum carburizing, which by its specification of work significantly reduce the emission of CO2and the duration of the process, without reducing the quality of the final product. The main aim of the paper is to present criteria for selection of carburizing parameters (mainly temperature increase) as a part of thermo-chemical treatment process performed using vacuum methods. Proper (higher to compare with conventional methods) carburizing process temperature is crucial in programming of carbon diffusion process meaning in process time and final carburized layer characteristics as carbon profile and homogeneity of the carburized layer.

Creation of a conductive surface layer on polypropylene samples by low‐pressure plasma treatments

1995 ◽  
Vol 77 (11) ◽  
pp. 5695-5701 ◽  
Author(s):  
M. Collaud Coen ◽  
P. Groening ◽  
G. Dietler ◽  
L. Schlapbach
Keyword(s):  
Surface Layer ◽  
Low Pressure ◽  
Pressure Plasma ◽  
Plasma Treatments ◽  
Conductive Surface ◽  
Low Pressure Plasma

scholarly journals STRUCTURE AND PROPERTIES OF THE SURFACE LAYER HIGH CHROME AUSTENITIC STEEL, SUBMITTED TO ION-PLASMA NITROGEN

2020 ◽  
pp. 805-815
Author(s):  
Юрий Федорович Иванов ◽  
Елизавета Алексеевна Петрикова ◽  
Сергей Витальевич Лыков ◽  
Юлия Александровна Денисова ◽  
Олег Сергеевич Толкачев
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Discharge Plasma ◽  
Low Pressure ◽  
Gas Discharge ◽  
Iron Nitride ◽  
Structure And Properties ◽  
Ion Nitriding ◽  
High Chromium ◽  
Gas Discharge Plasma

Ионное азотирование является одним из наиболее распространенных способов поверхностного упрочнения деталей и инструмента. Цель настоящей работы - выявление и анализ закономерностей преобразования структуры и свойств поверхностного слоя высокохромистой нержавеющей стали, подвергнутой низкотемпературному азотированию в плазме газового разряда низкого давления. Установлено, что насыщение азотом (793 К, 3 час.) аустенитной высокохромистой стали 202318 в плазме газового разряда низкого давления сопровождается формированием в слое толщиной (55 - 60) мкм структуры пластинчатого типа с чередующимися пластинами аустенита и нитрида железа (поперечные размеры пластин не превышают 10 нм), микротвердость и износостойкость которой превышают в 6,5 раз и более чем в 400 раз соответствующие характеристики исходного состояния. Ion nitriding is one of the most common methods of surface hardening of parts and tools. The purpose of this work is to identify and analyze the laws governing the transformation of the structure and properties of the surface layer of high-chromium stainless steel subjected to low-temperature nitriding in a low-pressure gas discharge plasma. It was found that the saturation with nitrogen (793 K, 3 hours) of austenitic high-chromium steel 20X23H18 in a low-pressure gas discharge plasma is accompanied by the formation of a plate type structure with alternating plates of austenite and iron nitride in a layer (55 - 60) µm thick (transverse plate sizes do not exceed 10 nm), the microhardness and wear resistance of which exceed the microhardness of the initial state by 6,5 times, wear resistance - more than 400 times.

scholarly journals Structure and properties of high-chromium steel irradiated with a pulsed electron beam and nitrided in a low-pressure gas discharge plasma

2021 ◽  
Vol 2064 (1) ◽  
pp. 012043
Author(s):  
Y Ivanov ◽  
E Petrikova ◽  
A Teresov ◽  
S Lykov ◽  
O Tolkachev ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Electron Beam ◽  
Low Pressure ◽  
Developed Countries ◽  
Gas Discharge ◽  
Iron Nitride ◽  
Complex Method ◽  
Two Phase ◽  
Pulsed Electron Beam

Abstract Ion-plasma saturation of the surface of machine parts and mechanisms with gas elements (nitrogen, oxygen, carbon) is currently one of the most effective and widely used methods of surface hardening of metal products for various purposes in the industry of developed countries. The aim of this research is to develop a complex method for modifying the surface layer of AISI 310 steel, combining irradiation with an intense pulsed electron beam and subsequent nitriding in the plasma of a low-pressure gas discharge. As a result of the studies performed, the optimal parameters of modification were revealed, which make it possible to increase the hardness of the surface layer of steel by more than 11 times, relative to the hardness of the initial material, and 8 times, relative to the hardness of steel irradiated with a pulsed electron beam. In this case, the wear resistance of the steel exceeds the wear resistance of the original and irradiated material by more than 100 times. It has been established that the high strength and tribological properties of the modified steel are due to the formation of a two-phase (iron nitride and chromium nitride) layered nanoscale structure in the surface layer.

BIOLOGICAL EFFECTS OF LOW-PRESSURE SEAWATER FLUSHING OF OILED SEDIMENTS

1987 ◽  
Vol 1987 (1) ◽  
pp. 439-443
Author(s):  
S. Howard ◽  
D. I. Little
Keyword(s):  
Shear Strength ◽  
Surface Layer ◽  
Water Table ◽  
Biological Effects ◽  
Low Pressure ◽  
Fuel Oil ◽  
Arenicola Marina ◽  
Intertidal Sand ◽  
Low Shear

ABSTRACT The objectives of this study were to assess the field effectiveness and biological effects of low-pressure saltwater flushing of a thin (<4 mm) oil layer applied to a very fine intertidal sand. On average approximately 85 percent of the applied medium fuel oil mousse was found to be recoverable. Hydrocarbon analyses indicated negligible oil incorporation into flushed plots. The technique is believed to have been effective partly because the water table was successfully raised (by up to 20 cm), and also because the surface 3 to 4 cm was sufficiently disturbed to liberate oil that had penetrated the surface layer during the 2 hours between oil application and flushing. Counts of Arenicola marina casts in “oiled” plots were significantly lower (P = 0.02) than in the “oiled and then flushed” plots. The technique is likely to work with viscous oils deposited in 10 mm thick Strandlines on accessible sloping shores, where the sediment is greater than 4 cm thick and reasonably firm. The technique is likely to be unsuccessful on very coarse sands and gravels, fluid muds, and low shear strength sands, because of erosion and mixing of sediments and oil.

Microseisms in New England—Case History II*

1948 ◽  
Vol 38 (3) ◽  
pp. 173-178
Author(s):  
L. Don Leet
Keyword(s):  
Surface Layer ◽  
Nova Scotia ◽  
Pressure Gradient ◽  
New England ◽  
Case History ◽  
Rayleigh Waves ◽  
Cold Front ◽  
Low Pressure ◽  
Storm Center ◽  
Set Up

Abstract Rayleigh waves recorded on the three components of the Harvard station are used to determine the direction of approach of microseisms. In Case History I, it was observed that microseisms did not radiate exclusively from the center of a well-developed low-pressure storm area and that they remained strong and continued for many hours after the storm center moved inland over Nova Scotia, northeast of the Harvard station, coming at that time from east, southeast, and south. In Case History II, a short but distinct microseismic storm ran its course as a cold front advanced to the coast and out over the ocean, but there was no atmospheric storm system within the region covered by the U. S. Weather Map. It is proposed that microseisms are generated when a pressure gradient of magnitude as yet undefined moves over the crust and, in effect, kneads the surface layer in such a way as to set up vibrations.

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