Thermal diffusion chromium plating of structural carbon steel 20 by high frequency currents

2021 ◽  
pp. 137-145
Author(s):  
N. I. Kitaev ◽  
Yu. V. Yakimovich ◽  
M. Yu. Shigaev ◽  
S. Ya. Pichkhidze
Keyword(s):  
High Frequency ◽  
Surface Hardness ◽  
Chromium Powder ◽  
Gear Teeth ◽  
Chromium Plating ◽  
High Shock ◽  
Temperature Diffusion ◽  
Diffusion Metallization ◽  
Steel 20 ◽  
Structural Carbon Steel

To increase the service life of the gear teeth made of steel 20, operating under high shock loads, their main surfaces were subjected to high-temperature diffusion metallization, namely, chromium plating with high-frequency currents. As a result of diffusion metallization, the surface hardness increased 5.1–5.4 times – from 156–159 HV to 800–866 HV, and the strength level 3.3 times – from 250 to 820 mAh. Optimal parameters for the diffusion metallization: current I = 0.25–0.3 kA, power Pe = 8–10 kW, hardening τ = 8–10 min. By the method of scanning electron microscopy, it was found that after diffusion saturation of the surface of the gear teeth with chromium, the steel has a homogeneous structure with clearly pronounced transition layers, the average thickness of the diffusion layer was 0.06 mm. Energy dispersive analysis showed that after diffusion metallization with chromium powder, the basic composition of the steel remained constant, only the qualitative ratio of the components changed. X-ray phase analysis revealed the presence of an αFe-phase with the incorporation of Cr on the surface of the sample.

Nitriding

2005 ◽  
pp. 227-244
Keyword(s):  
Heat Treatment ◽  
Surface Hardening ◽  
Elevated Temperatures ◽  
Surface Hardness ◽  
Ion Nitriding ◽  
Gear Teeth ◽  
Gas Nitriding ◽  
Aerospace Applications ◽  
High Shock ◽  
Hardening Heat Treatment

Abstract Nitriding is a surface hardening heat treatment that introduces nitrogen into the surface of steel while it is in the ferritic condition. Gas nitriding using ammonia as the nitrogen-carrying species is the most commonly employed process and is emphasized in this chapter. Nitriding produces a wear- and fatigue-resistant surface on gear teeth and is used in applications where gears are not subjected to high shock loads or contact stress. It is useful for gears that need to maintain their surface hardness at elevated temperatures. Gears used in industrial, automotive, and aerospace applications are commonly nitride. This chapter discusses the processes involved in gas, controlled, and ion nitriding.

Correlation of the diamond/matrix interphase zone structure with tool efficiency obtained by technology combining diamonds metallization with matrix sintering

2019 ◽  
pp. 111-123 ◽  
Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
V. I. Popov
Keyword(s):  
Thermal Diffusion ◽  
Shielding Effect ◽  
Specific Productivity ◽  
Grinding Wheel ◽  
Zone Structure ◽  
Chromium Powder ◽  
Carbide Matrix ◽  
Diffusion Metallization ◽  
Effect Of Copper ◽  
Diamond Retention

The paper studies structure and phase characteristics of the interphase zone diamond/matrix in dressers made by thermal diffusion metallization of a diamond combined with matrix sintering based on WC–Co and Cu impregnation. The compact arrangement of chromium powder particles around diamond grains and the shielding effect of copper foil create favorable conditions for thermal diffusion metallization of diamond at matrix sintering. A metallized coating chemically bonded with diamond and consisting of chromium carbide and solid solution of cobalt in chromium phases provides a strong diamond retention in the carbide matrix. It was shown that it is formed on the surface of the diamond under the conditions specified in the experiment and the temperature – time sintering mode. The specific productivity of experimental dresser made by hybrid technology at straightening green silicon carbide grinding wheel equaled 51.50 cm3/mg exceeding that of the control dresser made without metallization of diamonds by sintering with copper impregnation by 44.66%.

Effect of High-Frequency Induction Carburization on Ti6Al4V Alloy Tissue and Wear Performance

2021 ◽  
Vol 1032 ◽  
pp. 163-171
Author(s):  
Jing Guan ◽  
Xue Ting Jiang ◽  
Xing Cheng ◽  
Feng Yang ◽  
Jing Liu
Keyword(s):  
Wear Mechanism ◽  
High Frequency ◽  
Friction And Wear ◽  
Surface Hardness ◽  
Ti6al4v Alloy ◽  
Wear Properties ◽  
Alloy Matrix ◽  
The Coefficient Of Friction ◽  
Carburized Layer ◽  
High Frequency Induction

The surface of Ti6Al4V alloy was rapidly carburized by high-frequency electromagnetic induction heating under vacuum. The microstructure and hardness of the carburized layer were studied. The wear properties of the carburized layer were tested at 50, 100 and 200 rpm using the end face friction and wear device, and the wear mechanism was analyzed. The results show that the TiC strengthening phase was formed on the surface of Ti6Al4V alloy after high-frequency induction carburization, and the surface grains were refined. The surface hardness reaches 1116 HV0.25, but the brittleness of the carburized layer increases with increasing temperature. The amount of wear was reduced by 54% at 100 rpm. The roughness of the wear scar was reduced from 3.26 μm to 2.28 μm of Ti6A14V alloy matrix. The coefficient of friction and wear rate increases with increasing speed. The wear mechanism was transformed from adhesive wear and oxidative wear of the substrate to abrasive wear after carburizing.

Perspective of High Energy Heating Implementation for Steel Surface Saturation with Carbon

2014 ◽  
Vol 698 ◽  
pp. 351-354 ◽  
Author(s):  
Natalya V. Plotnikova ◽  
Anna Losinskaya ◽  
Vadim Yu. Skeeba ◽  
Ekaterina Nikitenko
Keyword(s):  
Electron Beam ◽  
High Frequency ◽  
Surface Hardness ◽  
High Energy ◽  
Current Treatment ◽  
Surface Layers ◽  
High Frequency Current ◽  
Electron Beam Deposition ◽  
Frequency Current ◽  
Beam Deposition

The possibility of obtaining of surface layers on low-carbon steel 20 by high-energy methods is shown. The features of structure formation in the surface layers after atmospheric electron-beam deposition of iron-graphite powder mixture and high-frequency current treatment are considered. It is shown that coatings with thickness of 2.6 mm and hardness of up to 8000 MPa are formed during atmospheric electron beam deposition. High-frequency current treatment allows to obtain coatings with thickness from 500 to 1600 μm, which hardness reaches 7000 MPa. Hardness increased is due to the formation of hypoeutectic cast iron structure or hypereutectoid steel during high-energy treatment, depending on the processing modes. It is expected that the increase in surface hardness will positively affect the wear resistance of high-carbon coatings.

Characteristics of High Frequency Peening Methods and their Effects on the Fatigue Strength of Welded Details

2007 ◽  
Vol 348-349 ◽  
pp. 429-432
Author(s):  
Imke Weich ◽  
Thomas Ummenhofer
Keyword(s):  
Fatigue Strength ◽  
Residual Stresses ◽  
High Frequency ◽  
Crack Detection ◽  
Surface Hardness ◽  
Detection Methods ◽  
Laser Measurements ◽  
Mechanical Effects ◽  
Weld Toe ◽  
Compressive Residual Stresses

Research has been initiated on the effects of high frequency peening methods on the fatigue strength. These methods combine an improvement of weld toe profile with an initiation of compressive residual stresses and surface hardening. The effects of two techniques, High Frequency Impact Treatment (HiFIT) and Ultrasonic Impact Treatemnt (UIT) are compared. Laser measurements of the weld seam prove that both methods increase the overall weld toe radii. Further, residual stress measurements verify the introduction of compressive residual stresses at least up to a depth of 1 mm. The values meet the yield strength combined with an increase of the surface hardness. These material mechanical effects cause an increased crack resistance. Crack detection methods prove that the material mechanical effects yield to a retarded crack initiation. Experimental results show that these effects lead to a significant increase of the fatigue strength and reduced slopes of the SN-curves.

Influence of the “Critical Velocity” Phenomenon on Chromium-Plated Gun Barrels

2003 ◽  
Vol 125 (3) ◽  
pp. 352-354
Author(s):  
Ju¨rg Ho¨lzle
Keyword(s):  
Critical Velocity ◽  
High Frequency ◽  
Pressure Wave ◽  
Design Criterion ◽  
Theoretical Studies ◽  
Chromium Plating ◽  
High Frequency Oscillations ◽  
Gun Barrel ◽  
Experimental And Theoretical Studies

A experimental 120 mm L55 tank gun barrel showed heavy loss of the chromium plating at the muzzle region. Experimental and theoretical studies led to the conclusion that high frequency oscillations, caused by the traveling pressure wave, are responsible for this effect. This so-called “critical velocity” phenomenon must be a design criterion for modern gun barrels.

The Parameters Affecting Strength Calculation of Gears

2014 ◽  
Vol 635 ◽  
pp. 30-34
Author(s):  
Silvia Medvecká-Beňová ◽  
Peter Frankovský ◽  
Iveta Janeková
Keyword(s):  
Bending Strength ◽  
Surface Hardness ◽  
High Hardness ◽  
Metallurgical Industry ◽  
Strength Calculation ◽  
Gear Teeth ◽  
Transmission Mechanisms ◽  
Heat Treated ◽  
Heat Treated Steel ◽  
Treated Layer

Safety and traffic flow of production facilities also depends upon the reliability of technical security equipment. Gearing in the transmission mechanisms must satisfy the conditions of strength calculation. This calculation consists of checking of the gear teeth on bend and contact. From the stress of gears is show that the basic requirements of the material are high hardness of works surfaces and bending strength. Steels best meet these conditions. Used steel with surface hardness up to 350 HBW, or heat treated steel with hardness of 500-650 HBW. The advantage of these materials is the high value of the contact pressure in the tough centre core of the tooth. As a final heat treatment are used surface hardening, cementation and hardening, nitridation and carbo-nitridation. Good properties of heat-treated steels are at the correct thickness of the heat-treated layer of the tooth. This paper considers the appropriate choice of parameters to obtain the desired level of safety of gears in a gearbox to drive the conveyor in the metallurgical industry under increased load.

A gear rattle model accounting for oil squeeze between the meshing gear teeth

2005 ◽  
Vol 219 (9) ◽  
pp. 1075-1083 ◽  
Author(s):  
R Brancati ◽  
E Rocca ◽  
R Russo
Keyword(s):  
High Frequency ◽  
Oil Viscosity ◽  
Damping Force ◽  
Oil Film ◽  
One Dimensional ◽  
Gear Teeth ◽  
High Frequency Vibrations ◽  
The Impact ◽  
Gear Rattle ◽  
Lubrication Conditions

In this paper a non-linear one-degree-of-freedom model for analysis of gear rattle vibrations in automotive manual transmissions is presented. In order to take into account the damping effects owing to the oil in the gap between two teeth of a meshing gear, a simple one-dimensional model for the oil-film squeeze effects is proposed. The squeeze model assumes that the damping force is proportional to the oil viscosity and to the extension of the oil film in the plane of curvature of the teeth, which may depend on the lubrication conditions (dry sump, splash, bath). The results provided from several numerical simulations, carried out with reference to helical involute tooth pairs, confirm the capability of oil in reducing the high-frequency vibrations subsequent to the impact between the teeth. In particular, the influence exerted by oil viscosity and gap extension on the rattle characteristics is investigated through the analysis of the transient response of the driven gear by imposing a harmonic motion to the driving gear.

Tooth Surface Fatigue of AISI9310 Steel Spur Gears

1992 ◽  
Author(s):  
H. Kotorii
Keyword(s):  
Service Life ◽  
Surface Hardness ◽  
Load Cycle ◽  
Tooth Profile ◽  
Tooth Surface ◽  
Spur Gears ◽  
Gear Teeth ◽  
Surface Fatigue ◽  
Profile Errors ◽  
Tooth Profile Errors

Abstract With a JIS 0 class Spur Gears of AISI9310 steel, module 4, presure angle 25 degree tooth profile, the numbers of pinion teeth 21 / gear teeth 29 carburized and tooth surface hardness HRc 59, the relationships of the load and the service life (S-N) diagram were investigated by running test on the power-circulated type gear tester. MIL-L-23699 equivalent synthetic oil at 50° C were fed at a ratio of 0.8 l/min and circumferential velocity of 8.8 m/sec. Also the running performance of the gears, variation of tooth profile errors, affairs of damage, etc. were examined. Types of tooth surface fatigue mere scoring, spalling, or micropitting. A durability limit of Hertz-stress was assumed to be around 2GPa at the load cycle of 108.

Sign in / Sign up

Export Citation Format

Share Document