scholarly journals Carbonitration of a Tool for Pressing Stainless Steel Pipes

2020 ◽  
Vol 7 (2) ◽  
pp. C17-C21
Author(s):  
I. V. Ivanov ◽  
M. V. Mohylenets ◽  
K. A. Dumenko ◽  
L. Kryvchyk ◽  
T. S. Khokhlova ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Heat Resistance ◽  
Alkali Metals ◽  
Matrix Ring ◽  
High Hardness ◽  
Operating Conditions ◽  
Matrix Rings ◽  
Conventional Heat Treatment ◽  
The Stability

To upgrade the operational stability of the tool at LLC “Karbaz”, Sumy, Ukraine, carbonation of tools and samples for research in melts of salts of cyanates and carbonates of alkali metals at 570–580 °C was carried out to obtain a layer thickness of 0.15–0.25 mm and a hardness of 1000–1150 НV. Tests of the tool in real operating conditions were carried out at the press station at LLC “VO Oscar”, Dnipro, Ukraine. The purpose of the test is to evaluate the feasibility of carbonitriding of thermo-strengthened matrix rings and needle-mandrels to improve their stability, hardness, heat resistance, and endurance. If the stability of matrix rings after conventional heat setting varies around 4–6 presses, the rings additionally subjected to chemical-thermal treatment (carbonitration) demonstrated the stability of 7–9 presses due to higher hardness, heat resistance, the formation of a special structure on the surface due to carbonitration in salt melts cyanates and carbonates. Nitrogen and carbon present in the carbonitrided layer slowed down the processes of transformation of solid solutions and coagulation of carbonitride phases. The high hardness of the carbonitrified layer is maintained up to temperatures above 650 °C. If the stability of the needle-mandrels after conventional heat treatment varies between 50–80 presses, the needles, additionally subjected to chemical-thermal treatment (carbonitration) showed the stability of 100–130 presses due to higher hardness, wear resistance, heat resistance, the formation of a special surface structure due to carbonitration in melts of salts of cyanates and carbonates. Keywords: needle-mandrel, matrix ring, pressing, heat treatment, carbonitration.

Behavior of Micro-Alloyed Steel at Thermal Treatment

2017 ◽  
Vol 265 ◽  
pp. 177-180 ◽  
Author(s):  
T.V. Shveyova ◽  
A.M. Pesin ◽  
D.O. Pustovoytov
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Microalloyed Steel ◽  
Alloyed Steel ◽  
Heavy Duty ◽  
Heavy Duty Vehicle ◽  
Micro Alloyed Steel ◽  
The Stability

A tendency towards the growth of grain when heating is investigated and the stability against tempering alloyed and microalloyed steel. The advantage steel, microalloyed by vanadium and nitrogen is shown and their application for heavy-duty vehicle parts is recommended. The possibility of residual forging heat of forgings realization for their heat treatment is established.

scholarly journals Simulation of thermal treatment of mineral wool blanket

2019 ◽  
Vol 298 ◽  
pp. 00091 ◽  
Author(s):  
Anton Pilipenko ◽  
Ekaterina Bobrova ◽  
Boris Efimov
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Mineral Wool ◽  
Energy Costs ◽  
Technological Parameters ◽  
Accelerated Methods ◽  
The Stability ◽  
Over Time

This article describes results of modelling of heat treatment of mineral wool blanket. The properties of mineral wool products are largely determined by the conditions of heat treatment, which is carried out by suction of the heat carrying agent through a layer of mineral wool blanket. The choice of technological parameters and optimization solutions determines both the energy costs of manufacturing mineral wool products and their properties and the stability of these properties over time when used in structures. Optimizing the heat treatment parameters of a mineral wool blanket is a labor-intensive and time-consuming task. The development of accelerated methods based on the analysis of the results of previously conducted and new studies can significantly reduce the time for choosing technological parameters, as well as increase the reliability and adequacy of decisions.

Wear and Corrosion Behavior of Functionally Graded Semi-Solid 9Cr18Mo Steel

2019 ◽  
Vol 285 ◽  
pp. 92-98
Author(s):  
Yong Jin Wang ◽  
Ren Bo Song ◽  
Jun Yanagimoto ◽  
Ya Ping Li
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
High Hardness ◽  
Skin Layer ◽  
Functionally Graded ◽  
High Concentration ◽  
Corrosion Failure ◽  
Wear And Corrosion ◽  
Conventional Heat Treatment

A kind of 9Cr18Mo multidiameter shaft part was fabricated through a designed thixoforging set-up. As compared with conventional heat treatment specimen, wear and corrosion behavior of 9Cr18Mo thixoforging specimen were studied. The results showed the surface of 9Cr18Mo thixoforging specimen demonstrated fine wear and corrosion resistance. Thixoforging specimen exhibited functionally graded property with inner austenite particles and fine dendrite eutectic skin layer. At the skin layer, the former solidified liquid led to the concentration of alloying elements such as Cr and Mo. Besides, eutectic structure of secondary austenite and M7C3carbide helped to improve the hardness. The high hardness of M7C3carbide and high concentration of Cr, Mo elements at the edge skin layer contributed to reducing the delamination wear, abrasive wear and the appearance of oxidation. Even at higher wear load, relative sliding occurred at the wear surface, which avoided crack formation and chunk spalling. As compared with conventional heat treatment specimen, corrosion current density of thixoforging surface reduced, while corrosion potential increased. Thixoforging surface also exhibited passivation behavior and the corrosion resistance increased slightly. High concentration of Cr and Mo at the skin layer avoided the formation of chromium depleted zone. In view that wear and corrosion failure tend to occur at the surface of specimen, the thixoforging specimen with a wear and corrosion skin layer might provide a possibility for expanding the application fields of 9Cr18Mo steel.

scholarly journals Effects of Primarily Solidified Dendrite and Thermal Treatments on the M23C6 Precipitation Behavior of High-Chromium White Iron

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1690
Author(s):  
Young-Gy Song ◽  
Jun-Seok Oh ◽  
Baig-Gyu Choi ◽  
Chang-Yong Jo ◽  
Je-Hyun Lee
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Low Temperature ◽  
M23c6 Carbide ◽  
Thermal Treatments ◽  
White Iron ◽  
Precipitation Behavior ◽  
High Chromium ◽  
Conventional Heat Treatment

The precipitation behavior of M23C6 carbide during thermal treatment of high-Cr white iron with various fractions of primarily solidified dendrite was studied and reviewed. M23C6 precipitation in the primarily solidified dendrite occurred preferentially during conventional heat treatment, whereas it occurred scarcely in the eutectic austenite. The reaction between M7C3 and austenite caused the dissolution of M7C3 into austenite, followed by precipitation of M23C6 along the periphery of eutectic M7C3. Relatively low-temperature thermal treatment (modified heat treatment) led to precipitation of M23C6 particles in the eutectic austenite, which is presumed to be caused by solubility difference depending on temperature.

scholarly journals The electrical conductivity of thin metallic films II— caesium and potassium on pyrex glass surfaces

1937 ◽  
Vol 158 (895) ◽  
pp. 718-728 ◽  
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Alkali Metals ◽  
Pyrex Glass ◽  
Metallic Films ◽  
Similar Investigation ◽  
The Stability ◽  
Glass Surfaces ◽  
Conductivity Of Thin Films

An account of an investigation of the electrical conductivity of thin films of rubidium deposited in high vacua on very clean glass surfaces has been previously published. It will be referred to in what follows as Part I. The method has now been used in a similar investigation using caesium and potassium. The vigorous heat treatment of the surface and vacuum technique described in Part I has again been found necessary in order to attain reproducible results, and the effects on contaminated surfaces are similar. It will be seen that the resistivities of the stable films are consistent with the theory given in Part I; moreover, the greater stability of the caesium films has supplied a test of the theory down to thicknesses of only a few A. The decay phenomena associated with the unstable films show a marked gradation through these three alkali metals, the stability of a given film increasing in the order potassium—rubidium—caesium.

Coverage and Stability of NHx Terminated Cobalt and Ruthenium Surfaces: a First Principles Investigation

2019 ◽  
Author(s):  
Ji Liu ◽  
Michael Nolan
Keyword(s):  
Metal Surfaces ◽  
High Vacuum ◽  
Atomic Layer ◽  
Nitrogen Plasma ◽  
Operating Conditions ◽  
Ultra High Vacuum ◽  
Bridge Site ◽  
Stable Surface ◽  
Saturation Coverage ◽  
The Stability

<div>In the atomic layer deposition (ALD) of Cobalt (Co) and Ruthenium (Ru) metal using nitrogen plasma, the structure and composition of the post N-plasma NHx terminated (x = 1 or 2) metal surfaces are not well known but are important in the subsequent metal containing pulse. In this paper, we use the low-index (001) and (100) surfaces of Co and Ru as models of the metal polycrystalline thin films. The (001) surface with a hexagonal surface structure is the most stable surface and the (100) surface with a zigzag structure is the least stable surface but has high reactivity. We investigate the stability of NH and NH2 terminations on these surfaces to determine the saturation coverage of NHx on Co and Ru. NH is most stable in the hollow hcp site on (001) surface and the bridge site on the (100) surface, while NH2 prefers the bridge site on both (001) and (100) surfaces. The differential energy is calculated to find the saturation coverage of NH and NH2. We also present results on mixed NH/NH2-terminations. The results are analyzed by thermodynamics using Gibbs free energies (ΔG) to reveal temperature effects on the stability of NH and NH2 terminations. Ultra-high vacuum (UHV) and standard ALD</div><div>operating conditions are considered. Under typical ALD operating conditions we find that the most stable NHx terminated metal surfaces are 1 ML NH on Ru (001) surface (350K-550K), 5/9 ML NH on Co (001) surface (400K-650K) and a mixture of NH and NH2 on both Ru (100) and Co (100) surfaces.</div>

ALMANITE W

Alloy Digest ◽  
1974 ◽  
Vol 23 (3) ◽  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Surface Treatment ◽  
High Hardness ◽  
Heat Treating ◽  
Austenitic Matrix ◽  
Matrix Type ◽  
Martensitic Matrix ◽  
Cast Condition

Abstract ALMANITE W comprises a series of three types of austenitic-martensitic white irons characterized by high hardness and relatively good impact strength. Type W1 has a pearlitic matrix. Type W2 has a martensitic matrix, Type W4 is highly alloyed to provide an austenitic matrix in the as-cast condition which may be further modified to give a martensitic matrix by heat treatment or by refrigeration. This datasheet provides information on composition, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-42. Producer or source: Meehanite Metal Corporation.

CPM REX 25

Alloy Digest ◽  
1980 ◽  
Vol 29 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
High Speed Steel ◽  
High Hardness ◽  
Heat Treating ◽  
High Speeds ◽  
Aisi Type ◽  
Tool Performance ◽  
End Mills ◽  
Machining Operations

Abstract CPM REX 25 is a super high-speed steel made without cobalt. It is comparable to AISI Type T15 cobalt-containing high-speed steel in response to heat treatment, properties, and tool performance. CPM REX 25 is recommended for machining operations requiring heavy cuts, high speeds and feeds, and difficult-to-machine materials of high hardness and abrasion resistance. Typical applications are boring tools, drills, gear cutters, punches, form tools, end mills and broaches. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-365. Producer or source: Crucible Materials Corporation.

On corrosion properties of ceramic materials for pump friction pairs in lead – bismuth environment

2019 ◽  
pp. 116-122
Author(s):  
V. V. Stepanov ◽  
A. D. Kashtanov ◽  
S. U. Shchutsky ◽  
A. N. Agrinsky ◽  
N. I. Simonov
Keyword(s):  
Composite Materials ◽  
Heat Resistance ◽  
Experimental Research ◽  
Ceramic Materials ◽  
Operating Conditions ◽  
Metallic Materials ◽  
Corrosion Properties ◽  
Liquid Coolant ◽  
Radial Bearing ◽  
Axial Pump

We consider the results of studies on the choice of material of the lower radial bearing of the pump, designed to circulate the coolant lead – bismuth. The circulation of the liquid coolant is provided by a vertical axial pump having a “long” shaft. In this design it is necessary to provide for the lower bearing the lubrication carried out with lead – bismuth coolant. Having analyzed the operating conditions of the axial pump, we decided to carry out the lower bearing in accordance with the scheme of a hydrodynamic sliding bearing. The materials of friction pairs in such a bearing must withstand the stresses arising from the operation of the pump, as well as the aggressive conditions of the coolant. Non-metallic materials – ceramics and carbon-based composite materials – were selected basing on the study of literature data for experimental research on the corrosion and heat resistance in the lead-bismuth environment. 

Viability of turbine blade material with a long service life

2019 ◽  
pp. 28-35
Author(s):  
O. B. Berdnik ◽  
I. N. Tsareva ◽  
M. K. Chegurov
Keyword(s):  
Heat Treatment ◽  
Service Life ◽  
Yield Strength ◽  
Mechanical Characteristics ◽  
Operating Time ◽  
Structural Features ◽  
Operating Conditions ◽  
Standard Methods ◽  
Experimental Values ◽  
Plasticity Coefficient

This article deals with structural features and characteristic changes that affect the mechanical characteristics after different service life in real conditions using the example of the blades of the 4th stage of turbine GTE-45-3 with an operating time of 13,000 to 100,000 hours. To study the change in the state of the material under different operating conditions, determine the degree of influence of heat treatment on the regeneration of the microstructure, and restore the mechanical characteristics of the alloy after different periods of operation, non-standard methods were used: relaxation tests on miniature samples to determine the physical yield strength and microplasticity limit and quantitative evaluation of the plasticity coefficient of the material from experimental values of hardness, which allow us to identify the changes occurring in the microvolumes of the material and predict the performance of the product as a whole.

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