Mechanical and Metallurgical Properties of Grade X70 Steel Linepipe Produced by Non-conventional Heat Treatment

This article describes the concept of uphill quenching process applied in the heat treatment of aluminum alloys. Uphill quenching is interesting since residual stress reductions of up to 80% has been reported. In addition, substantial improvements in dimensional stability have been achieved for several types of aluminum parts. Often, uphill quenching is applied after quenching and before aging during the heat treatment of aluminum alloys. The uphill quenching process consists of the immersion of the part in a cryogenic environment, and after homogenization of the temperature, the part is transferred to the hot steam chamber to obtain a temperature gradient that will maintain the mechanical properties gained with this process. The results obtained are lower residual stress and better dimensional stability. The aim of this article is to provide a review of this process and to compare it with conventional heat treatment.

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Physical and Numerical Simulations of Closed Die Hot Forging and Heat Treatment of Forged Parts

Materials ◽

10.3390/ma14010015 ◽

2020 ◽

Vol 14 (1) ◽

pp. 15

Author(s):

Łukasz Poloczek ◽

Łukasz Rauch ◽

Marek Wilkus ◽

Daniel Bachniak ◽

Władysław Zalecki ◽

...

Keyword(s):

Heat Treatment ◽

Grain Size ◽

Numerical Simulations ◽

Phase Transformations ◽

Hot Forging ◽

Transformation Model ◽

Controlled Cooling ◽

Austenite Grain Size ◽

Austenite Grain ◽

Conventional Heat Treatment

The paper describes physical and numerical simulations of a manufacturing process composed of hot forging and controlled cooling, which replace the conventional heat treatment technology. The objective was to investigate possibilities and limitations of the heat treatment with the use of the heat of forging. Three steels used to manufacture automotive parts were investigated. Experiments were composed of two sets of tests. The first were isothermal (TTT) and constant cooling rate (CCT) dilatometric tests, which supplied data for the identification of the numerical phase transformation model. The second was a physical simulation of the sequence forging-cooling on Gleeble 3800, which supplied data for the validation of the models. In the numerical part, a finite element (FE) thermal-mechanical code was combined with metallurgical models describing recrystallization and grain growth during forging and phase transformations during cooling. The FE model predicted distributions of the temperature and the austenite grain size in the forging, which were input data for further simulations of phase transformations during cooling. A modified JMAK equation was used to calculate the kinetics of transformation and volume fraction of microstructural constituents after cooling. Since the dilatometric tests were performed for various austenitization temperatures before cooling, it was possible to include austenite grain size as a variable in the model. An inverse algorithm developed by the authors was applied in the identification procedure. The model with optimal material parameters was used for simulations of hot forging and controlled cooling in one of the forging shops in Poland. Distributions of microstructural constituents in the forging after cooling were calculated. As a consequence, various cooling sequences during heat treatment could be analyzed and compared.

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Carbonitration of a Tool for Pressing Stainless Steel Pipes

Journal of Engineering Sciences ◽

10.21272/jes.2020.7(2).c3 ◽

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.

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Intense pulsed UV light treatment to design functional optical films from perhydropolysilazane: an alternative to conventional heat treatment processes

Journal of Materials Science ◽

10.1007/s10853-021-06598-3 ◽

2022 ◽

Author(s):

Jeong Ju Baek ◽

Sung Man Park ◽

Yeong Rang Kim ◽

Ki Cheol Chang ◽

Youn-Jung Heo ◽

...

Keyword(s):

Heat Treatment ◽

Uv Light ◽

Light Treatment ◽

Treatment Processes ◽

Conventional Heat Treatment ◽

Optical Films ◽

Pulsed Uv Light

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THE NEW HEAT TREATMENT TECHNOLOGY OF A356 ALUMINIUM ALLOY PREPARED BY PTC

International Journal of Modern Physics B ◽

10.1142/s0217979209060221 ◽

2009 ◽

Vol 23 (06n07) ◽

pp. 906-913 ◽

Cited By ~ 1

Author(s):

LIANYONG ZHANG ◽

YANHUA JIANG ◽

ZHUANG MA ◽

WENKUI WANG

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Heat Treatment ◽

Tensile Strength ◽

Treatment Process ◽

A356 Alloy ◽

Heat Treatment Process ◽

X Rays ◽

Treatment Technology ◽

Conventional Heat Treatment

Phase Transition Cooling (PTC), using the absorbed latent heat during the melting of phase transition cooling medium to cool and solidify alloys in the process of casting, is a new casting technology. Specimens of A356 casting aluminum alloy were prepared by this method in the paper. The new heat treatment process (cast and then aging directly without solid solution) of A356 alloy was performed. For comparison, the conventional T6 heat treatment (solution and then aging treatment) was performed too. The mechanical properties of A356 alloy with different heat treatments were measured by tensile strength testing methods and microstructures of the alloy with different heat treatment process were investigated by optical microscopy (OM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-rays diffraction (XRD) and transmission electron microscopy (TEM) too. The results show that ultimate tensile strength (UTS) of A356 alloy with the new heat treatment process is much higher than that with conventional heat treatment while the elongations with the two heat treatment processes are very close. This is due to the grain refinement obtained after PTC processing.

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Machine Design for Multiscale Nitinol Annealment Process and End Product Performance Analysis

ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems ◽

10.1115/smasis2020-2290 ◽

2020 ◽

Author(s):

Amanda Skalitzky ◽

Stuart Coats ◽

Ramsis Farag ◽

Austin Gurley ◽

David Beale

Keyword(s):

Heat Treatment ◽

Treatment Process ◽

Heat Treating ◽

Experimental Results ◽

Heat Treatment Process ◽

Scanning Calorimetry ◽

Niti Wire ◽

Annealing Temperatures ◽

Conventional Heat Treatment ◽

Post Production

Abstract The functional properties of Nitinol (NiTi) are set by composition, production process, and post-production heat treatment and cold working. Post-production heat treating is dependent on two main parameters: anneal temperature and aging time. Most heat-treating processes performed by researchers generally consist of simple temperature soaks at specified aging times. However, there are drawbacks to this method. More complex heat treatments can result in performance improvements, but they are difficult to implement and often proprietary to manufacturers and therefore not widely used by researchers. By designing a Continuously-Fed heat treatment System (CFS), this work demystifies this complex heat-treatment process by rapidly heat-treating NiTi wire samples across a range of annealing temperatures, soak times, and tensions with little human intervention. This automated process ensures samples are created in a consistent manner and results in a much more consistent end-product when compared to conventional heat-treating methods. Using the CFS, a gamut of samples with varying annealing temperatures (400–550°C) and aging times (1–3 minutes) were created with 0.25mm diameter high-temperature actuator wire initially in the ‘as-drawn’ condition. Differential Scanning Calorimetry (DSC) analysis was performed to determine how the transition temperature(s) change with the various heat-treating parameters and the mechanical properties of the wire were determined utilizing a tensile test. The experimental results demonstrate the benefits of the CFS and are compared to those of a more conventional heat treatment process. Experimental results show that high-performance Nitinol actuator behavior can consistently be achieved using the CFS. Optimal heat treatment processes can be determined quickly experimentally.

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