Fast Salt Bath Heat Treatment for a Bainitic/Martensitic Low-Carbon Low-Alloyed Steel

Problem statement. In recent decades, there has been a tendency to increase the mechanical properties of low-carbon, low-alloyed steel plate iron by using controlled rolling or hardening heat treatment of finished steel parts. At the same time, for welded parts, the most suitable is a metal having a ferrite-bainite (or bainite) structure. The work investigated the features of the ferrite-bainite structure of low-carbon and low-alloyed steel 15ХСНД for the production of connecting pipeline parts. Purpose of the article. To establish the laws of formation of a ferritic-bainitic structure in low-carbon low-alloy steels depending on the parameters of heat treatment. Determine the effect of heat treatment parameters on the properties of the connecting parts of pipelines made of these steels. Conclusion. The regularities of the influence of heat treatment parameters on the structure, mechanical properties and topography of fractures of impact samples of 15ХСНД steel with a ferrite-bainitic structure are established. Keywords: stamped-welded connecting parts of man pipelines; heat treatment; microstructure; bainite;mechanical properties; fractography

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Study on the Influence of Carbon on Standardized and Non-Standardized Steel

Acta Marisiensis. Seria Technologica ◽

10.2478/amset-2019-0003 ◽

2019 ◽

Vol 16 (1) ◽

pp. 14-18

Author(s):

Liviu Dorin Pop

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Carbon Steel ◽

Low Carbon Steel ◽

Heat Treating ◽

Alloyed Steel ◽

Basic Knowledge ◽

Low Carbon ◽

Close Link ◽

High Alloyed Steel

Abstract The way a piece or tool behaves in operation is determined by the quality of the material from which it is made, the precision of execution and heat treatment applied. In the present research, it is highlighted the differences that take shape after heat treating different materials (low carbon steel and high alloyed steel) including heating to dissimilar austenitic phases (880°C and 1020°C), holding for non-identical times, tempering at low temperature (260 °C) and then cooling by using separate cooling mediums (oil, air and water). The results show no noticeable increase in the hardness and mechanical properties for the low carbon steel after the heat treatment, but on the other hand, the high alloyed steel, reveals distinguishable changes in both hardness and mechanical properties. There is a close link between the structure, the parameters of the thermal processes and the properties that are desired so that future specialists have to assimilate the basic knowledge related to the phenomena that occur during a heat treatment but at the same time it is important to equip the companies with machines and measure devices, like a spectrometer.

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Enhanced Mechanical Properties of a 0.22C-Mn-Si-Cr Low Alloyed Steel Treated by ART and Q&P Processes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1004-1005.203 ◽

2014 ◽

Vol 1004-1005 ◽

pp. 203-208

Author(s):

Bai Feng An ◽

Gu Hui Gao ◽

Xiao Lu Gui ◽

Zhun Li Tan ◽

Bing Zhe Bai

Keyword(s):

Retained Austenite ◽

Low Carbon Steel ◽

High Strength Steels ◽

High Strength ◽

Total Elongation ◽

Alloyed Steel ◽

Low Carbon ◽

Multiphase Microstructure ◽

Element Enrichment ◽

Low Alloyed Steel

There is a currently desirable demand for high strength steels with good ductility reduce the weight of steel parts for automobile and train applications. Retained austenite in steels can improve the toughness and plasticity. The austenite reverse transformation + quenching and partitioning (ART + Q&P) process was treated on a 0.2C-Mn-Si-Cr low alloyed steel, a multiphase microstructure composed of intercritical ferrite (IF), martensite, bainite and retained austenite (RA) can be obtained in the low carbon steel. Microstructures of the steel treated by different heat treatments were characterized by SEM and XRD. Results show that the formation of RA in low alloy steel depends on the following: (1) the enrichment of the carbon and manganese in the reversed austenite during the ART step; (2) the secondary enrichment of carbon in retained austenite during the following Q&P step. High fraction of RA (14vol.%) was obtained through the two-step element enrichment treatment (ART + Q&P). Due to continuous TRIP effect of RA during the deformation, a good combination of strength and plasticity was achieved in our works: the product of strength and elongation is greater than 35 GPa•%, the tensile strength is more than 1230 MPa, the yield strength greater than 890 MPa, the total elongation is about 28.6%.

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Research of recrystallization processes in lowcarbon low-alloyed steel during high-temperature rolling modeling

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2019-97-1-15-27 ◽

2019 ◽

pp. 15-27

Author(s):

S. V. Korotovskaya ◽

O. V. Sych ◽

E. I. Khlusova ◽

E. A. Yashina

Keyword(s):

Plastic Deformation ◽

High Temperature ◽

Deformation Temperature ◽

Static Recrystallization ◽

Thermomechanical Processing ◽

Microstructural Analysis ◽

Alloyed Steel ◽

Temperature Deformation ◽

Low Carbon ◽

Low Alloyed Steel

Processes of dynamic and static recrystallization occurring at different conditions of plastic deformation (reduction modes, deformation temperature) of low-carbon low-alloyed steel are under consideration. Modeling of thermomechanical processing is carried out at Gleeble 3800, followed by complex microstructural analysis. Temperature-deformation conditions leading to formation of uniform dispersed structure are revealed during the investigations. In conclusion the results of implementation in industry of worked out hot rollingmodes are given.

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Using Electron Beam to the Surface Heat Treatment of the Carbon Steels

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.34.10 ◽

2019 ◽

Vol 34 ◽

pp. 10-17

Author(s):

Adriana Zara ◽

Maria Stoicănescu ◽

I. Giacomelli

Keyword(s):

Heat Treatment ◽

Electron Beam ◽

Carbon Steel ◽

Superficial Layer ◽

Carbon Steels ◽

Surface Heat ◽

Alloyed Steel ◽

Mechanical Products ◽

Low Alloyed Steel ◽

Working Parameters

Usage of electron beam shows the possibility of using its energy in different thermic processes. Among these, it is found the heating of mechanical products for the surface heat treatment. During the effectuated practical attempts, two types of construction steels were analyzed, namely carbon steel (OLC 45) and a low alloyed steel (41 Cr 4). The electron beam was applied on samples that were previous subjected to the heat treatment of improvement. The working parameters were chosen in order to obtain the heating of the superficial layer without melting. The samples treated as above were subjected to studies regarding the metallographic structures and the resulted hardness; also there were effectuated wear attempts. It was concluded that the use of electron beam in superficial heat treatment may also fit in practical terms.

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Effect of cooling rate on the microstructure and mechanical properties of a low-carbon low-alloyed steel

Journal of Materials Science ◽

10.1007/s10853-021-05974-3 ◽

2021 ◽

Author(s):

Hongcai Wang ◽

Lijie Cao ◽

Yujiao Li ◽

Mike Schneider ◽

Eric Detemple ◽

...

Keyword(s):

Mechanical Properties ◽

Volume Fraction ◽

Plate Thickness ◽

Microstructural Characterization ◽

Mechanical Tests ◽

Alloyed Steel ◽

Low Carbon ◽

Cooling Rates ◽

Heavy Plate ◽

Low Alloyed Steel

AbstractHeavy plate steels with bainitic microstructures are widely used in industry due to their good combination of strength and toughness. However, obtaining optimal mechanical properties is often challenging due to the complex bainitic microstructures and multiple phase constitutions caused by different cooling rates through the plate thickness. Here, both conventional and advanced microstructural characterization techniques which bridge the meso- and atomic-scales were applied to investigate how microstructure/mechanical property-relationships of a low-carbon low-alloyed steel are affected by phase transformations during continuous cooling. Mechanical tests show that the yield strength increases monotonically when cooling rates increase up to 90 K/s. The present study shows that this is associated with a decrease in the volume fraction of polygonal ferrite (PF) and a refinement of the substructure of degenerated upper bainite (DUB). The fine DUB substructures feature C-rich retained austenite/martensite-austenite (RA/M-A) constitutes which decorate the elongated micrograin boundaries in ferrite. A further increase in strength is observed when needle-shaped cementite precipitates form during water quenching within elongated micrograins. Pure martensite islands on the elongated micrograin boundaries lead to a decreased ductility. The implications for thick section plate processing are discussed based on the findings of the present work.

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