scholarly journals Energy power parameter effect of hot rolling on the formation of the structure and properties of low-alloy steels

2021 ◽  
Vol 6 (12 (114)) ◽  
Author(s):  
Sergey Sheyko ◽  
Anton Matiukhin ◽  
Volodymyr Tsyganov ◽  
Andrey Andreev ◽  
Anna Ben ◽  
...  
Keyword(s):  
Hot Deformation ◽  
Relative Elongation ◽  
Motor Vehicles ◽  
Accelerated Cooling ◽  
Low Alloy Steels ◽  
Two Phase ◽  
Plastic Properties ◽  
Alloy Steels ◽  
Increased Strength ◽  
Effect Of Hot Rolling

The temperature and degree of hot deformation for steel 10HFTBch have been determined. This made it possible to ensure an increase in the mechanical properties of this steel, namely, the ultimate strength up to 540–560 MPa, as well as the relative elongation up to 25–29 %. As a result, it became possible to increase the service life of wheels with increased carrying capacity. This, in turn, will make it possible to increase the load of the transported cargo by motor vehicles several times. The mechanism of the influence of the energy-power parameters of rolling on the formation of the macro- and microstructure of a two-phase steel in the process of hot deformation is disclosed. The applied scheme provided an increase in the homogeneity of the structure of the developed steel, which saved the central part of the rolled section from overheating. It has been established that a decrease in the temperature of the end of deformation leads to a decrease in the size of the recrystallized austenite grain, and, consequently, to a refinement of the ferrite grain. Also an important factor in preventing the growth of ferrite grains in the upper part of the ferritic region is the abolition of cooling of the steel in coils. The recommended mode for multicomponent alloy steel 10HFTBch is as follows: the temperature of the end of rolling is 850 °C, the beginning of accelerated cooling is 750 °C, and the temperature of strip coiling into a coil is 600 °C. The basis for ensuring the increased strength of two-phase steels is the ratio and distribution of structural fractions – ferrite (initial and precipitated from austenite), as well as martensite. When hardened by such traditional "martensite formations" as manganese, the ability to control properties is limited. This is reflected in a narrow range of variation in the strength and ductility of the developed steel. The optimal combination of strength characteristics of plastic properties reduces the metal consumption of the product by 15–25 %.

Scientific and technological bases for creation of cold-resistant steel with a guaranteed yield strength of 315–750 MPa for the Arctic. Part 2. Technology of production, structure and properties of sheet hire performance

2019 ◽  
pp. 14-41
Author(s):  
O. V. Sych
Keyword(s):  
Yield Strength ◽  
Thermomechanical Processing ◽  
The Arctic ◽  
Accelerated Cooling ◽  
Low Alloy Steels ◽  
Hot Plastic Deformation ◽  
Metal Thickness ◽  
Alloy Steels ◽  
Technology Of Production ◽  
Technological Methods

On the basis of the conducted research, a complex of scientific and technological methods has been developed for various technological processes (thermomechanical processing with accelerated cooling, quenching from rolling and separate furnace heating with high-temperature tempering). The developed method provides the formation of the structure of acceptable heterogeneity and anisotropy according to different morphological and crystallographic parameters throughout the thickness of rolled products up to 100 mm from low alloy steels with a yield strength of at least 315–460 MPa and up to 60 mm from economically alloyed steels with a yield strength of at least 500–750 MPa. The paper presents results of the industrial implementation of hot plastic deformation and heat treatment schemes for the production of cold rolled steel sheet with yield strength of at least 315–750 MPa for the Arctic. The structure of sheet metal thickness is given, providing guaranteed characteristics of strength, ductility, cold resistance, weldability and crack resistance.

Analysis of Recrystallization Behavior of Hot-Deformed Austenite Reconstructed from EBSD Orientation Maps of Lath Martensite

2016 ◽  
Vol 879 ◽  
pp. 2389-2394
Author(s):  
Manabu Kubota ◽  
Kohsaku Ushioda ◽  
Goro Miyamoto ◽  
Tadashi Furuhara
Keyword(s):  
Hot Deformation ◽  
Lath Martensite ◽  
New Method ◽  
Reconstruction Method ◽  
Low Alloy Steels ◽  
Recrystallization Behavior ◽  
Compression Direction ◽  
Orientation Map ◽  
Alloy Steels ◽  
Parent Austenite

The recrystallization behavior of hot-deformed austenite of 0.55% C low alloy steels at 900, 850 and 800°C was investigated by a conventional double-hit compression test and a new method which reconstructs the parent austenite orientation map from an EBSD (electron backscattering diffraction) orientation map of daughter lath martensite. The new method can clearly reconstruct the parent austenite structure at high temperature from the daughter lath martensite structure and we can obtain the information on crystal orientation of the work-hardened austenite. It was revealed that recrystallization of austenite at 800 °C is significantly retarded by the addition of 0.1% V. The strong texture of <110> parallel to the compression direction develops just after the hot-deformation, but this texture becomes weaker as the recrystallization progresses. By applying the reconstruction method, it becomes possible to evaluate various phenomena related to the hot-deformation of austenite

Kinetics of nitrided layers formation on low-alloy steels in the gas nitriding process

2020 ◽  
Vol 24 (4) ◽  
pp. 31-36
Author(s):  
Grzegorz Wójcik ◽  
Barbara Kucharska ◽  
Piotr Wach
Keyword(s):  
Diffusion Layer ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Nitriding Process ◽  
Process Time ◽  
Low Alloy Steels ◽  
Two Phase ◽  
Gas Nitriding ◽  
Alloy Steels ◽  
Kinetics Of

The study examined cylindrical samples made of low-alloy structural steel 42CrMo4 (40HM) and 41CrAlMo7 (38HMJ) subjected to the nitriding process at 540oC during 2, 7, 12 and 17 hours. During the first 2 hours of the process, the atmosphere was ammonia, while the rest of the process was carried out in the atmosphere consisting of 50% ammonia and 50% dissociated ammonia. After the process, surface hardness, hardness distribution at the depth of 50 µm from the surface up to the hardness of the core, and microstructure of the nitrided layer produced were examined. It has been shown that along with the extension of the duration of the nitriding process on 40HM steel, the surface thickness of the layer of nitrides increases from 6 µm after 2 hours to 14 µm after 17 hours of the process and this layer has a two-phase structure (+’), while the thickness of the diffusion layer was from 0.15 to 0.44 mm (depending on the process time). In the case of 38HMJ steel, the thickness of the layer of nitrides increased from 1 µm after 2 hours to 9.5 µm after 17 hours. The thickness of the diffusion layer was from 0.08 to 0.35 µm (depending on the process time).

Effect of Hot Work on Hardness and Impact Toughness of Heat Treated Low Alloy Steels

2014 ◽  
Vol 1082 ◽  
pp. 197-201
Author(s):  
Mahmoud M. Tash ◽  
Saleh A. Alkahtani ◽  
Khaled A. Abuhasel
Keyword(s):  
Impact Toughness ◽  
Hot Forging ◽  
Weight Ratio ◽  
High Strength ◽  
Extensive Study ◽  
Low Alloy Steels ◽  
Alloying Additions ◽  
Heat Treated ◽  
Alloy Steels ◽  
Effect Of Hot Rolling

The present study was undertaken to investigate the effect of hot work reduction ratio on the hardness and impact toughness of different grades of low alloy steels. The effect of hot rolling and hot forging with different reduction ratios on the hardness and impact toughness properties will be studied. An extensive study will be carried out to investigate the effect of alloying additions and TMT parameters on the hardness and impact toughness of heat-treated low alloy steels. An understanding of the combined effect of TMT and heat treatment on the hardness and impact toughness of the low alloy steels would help in selecting conditions required to achieve optimum mechanical properties and alloy high strength to weight ratio.

Quantitative Analysis of Carbon in Ferrite in Dual-Phase Steels by Mechanical Loss Measurements

2012 ◽  
Vol 184 ◽  
pp. 87-91 ◽  
Author(s):  
K. Honda ◽  
K. Nakano ◽  
Hiroshi Numakura ◽  
T. Yokoi ◽  
D. Maeda ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Single Phase ◽  
Complex Structure ◽  
Ferrite Phase ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Mechanical Loss ◽  
Two Phase ◽  
Alloy Steels ◽  
Snoek Relaxation

To establish the method for determining the amount of carbon in the ferrite phase in ferrite + martensite dual-phase low-alloy steels, mechanical loss measurements have been performed on a series of Fe–C alloys with varying constitution. The observed mechanical loss spectra of two-phase alloys turned out to be simple superposition of those of single phase alloys, of ferrite and of martensite. The concentrations of carbon in solution evaluated from the magnitude of the Snoek relaxation in the two-phase alloys agree well with those expected from the Fe–C phase diagram. It is thus possible to selectively analyse the carbon dissolved in the ferrite phase in the complex structure, at least in simple binary alloys.

Use of Ammonia to Supress Oxygen Production and Corrosion in Boiling-Water Reactors

CORROSION ◽  
1967 ◽  
Vol 23 (3) ◽  
pp. 57-64 ◽  
Author(s):  
L. E. LESURF ◽  
P. E. C. BRYANT ◽  
M. G. TANNER
Keyword(s):  
Stainless Steels ◽  
Boiling Water ◽  
Boiling Water Reactors ◽  
Low Alloy Steels ◽  
Oxygen Production ◽  
Two Phase ◽  
Alloy Steels ◽  
Ammonia Addition ◽  
Water Reactors ◽  
Different Origins

Abstract Radiolysis of the coolant in nuclear reactors cooled by boiling water results in oxygen in the steam and recirculated water phases. This has dictated the use of stainless steels as the major circuit materials for these reactors. It is shown that ammonia additions to the coolant eliminate oxygen production, permitting the use of mild steel for circuit construction with consequent savings in capital cost Corrosion data are presented for various out-reactor materials (carbon steel, low alloy steels, stainless steels, Monel alloy 400, Inconel alloy 600) exposed out-of-flux to the coolant of two phase in-reactor loops when operated neutral and with ammonia addition. Activation of corrosion products from different origins is discussed. Intergranular attack is related to the presence of oxygen or oxidizing radiolytic species in the water.

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