Articolele autorului Ripeanu Razvan George
Link la profilul stiintific al lui Ripeanu Razvan George

Tribological Behavior of Metalworking Fluids

In order to formulate new ecological metalworking fluids, the paper presents the tests made in first phase on universal tests machines as: ball-on-disk CSM micro-tribometer at different loads with 6 mm ball of 100Cr6 and the disks were made of carbon steel, in the presence of fluid samples with different complex esters and concentrations, in order to establish the proper composition. On Amsler A135 machine, was established the tribological behavior

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Heat exchangers tube to tube sheet joints corrosion behavior

Paper presents the studies made by the authors above the tube to tube sheet fittings of heat exchanger with fixed covers from hydrofining oil reforming unit. Tube fittings are critical zones for heat exchangers failures. On a device made from material tube and tube sheet at real joints dimensions were establish axial compression force and traction force at which tube is extracted from expanded joint. Were used two shapes joints with two types of

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The Tribologic Properties of Fatty Acid Methyl Esters and Single Wall Carbon Nanotubes
Soil Resistivity Around Gas Pipelines

Paper contains some aspects regarding soil resistivity around underground gas pipelines. The main factors that affect pipelines durability, resulted in this work are shown.

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Aggressivity of Hair Shampoo above Stainless Steel Type AISI 316L

Paper contains some aspects regarding the corrosion behavior of stainless steel type AISI 316L in hair shampoo medium. The electrochemical parameters by potentiodynamic methods at different temperatures and also corrosion rate by gravimetric methods for stainless steel type 316L with passive layer and without passive stratum were established. The medium and temperature influence above corrosion rate are shown in the work

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Nitriding Treatments Influence Above Tribologic Behavior of Austenitic Stainless Steels

Austenitic stainless steels tribological behavior could be improved by thermal treatments. Gases nitriding and plasma nitriding treatments applied on AISI 316 and AISI 304 reduce friction coefficients and wear. The aim of the work was to confirm the advantage of plasma nitriding treatment in rising friction couples durability made of austenitic stainless steels.

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Research regarding the improvements of tribological behavior in three cone bits bearings

Sliding bearings in three cone bits are lubricated in heavy conditions. To improve tribological behavior, samples of bearings materials were made with implants of antifriction materials with different rapport between implant and free base material in the presence of different greases. Antifriction material has a greater dilatation coefficient than base material. If the implant dimension is too small, the solid lubricant capability to cover the base

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Structure and properties of Zr/ZrCN coatings deposited by cathodic arc method

Zr/ZrCN multilayers, with bilayer periods ranging from 4.4 to 70 nm, were deposited on C45 and M2 steels and Si substrates by the cathodic arc technique, in a CH4 +N2 atmosphere. The elemental and phase composition, modulation periodicity, texture, surface morphology, residual stress, hardness, adhesion, friction and wear behavior were investigated as a function of bilayer period and C/N ratio using AES, RBS, XRR, XRD and AFM techniques, surface

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Influence of Bilayer Period on the Characteristics of Nanometre-Scale ZrN/TiAlN Multilayers
Characteristics of arc plasma deposited TiAlZrCN coatings