scholarly journals Effect of heat treatment residual stress on stress behavior of constant stress beam

2017 ◽  
Vol 5 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Si Young Kwak ◽  
Ho Young Hwang
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
External Load ◽  
Treatment Process ◽  
Constant Stress ◽  
Design Stage ◽  
Treatment Processes ◽  
Stress Behavior ◽  
Treatment Step ◽  
Heat Treatment Step

Abstract Although most casting and heat treatment processes generate significantly high residual stress in the products, this factor is generally not taken into account in the design stage of the product. In this study, experimental study and numerical analysis were conducted on a constant stress beam to examine effects of the residual stress generated during the heat treatment process on yielding behavior of the product in use. A constant stress beam of SUS 304 was designed in order to test the stress behavior related to residual stress. The residual stresses generated during quenching heat treatment of the beam were measured in advance by ESPI (Electronic Speckle-Pattern Interferometry) equipment, and then the external stresses generated while applying a simple external load on the beam were measured. Also, the residual stress distribution generated during the heat treatment process was computed using a numerical analysis program designed for analyzing heat treatment processes. Then, the stress distribution by a simple external load to the beam was combined with the calculated residual stress results of the previous heat treatment step. Finally, the results were compared with experimental ones. Simulation results were in good agreement with the experimental results. Consistency between experimental results and computational results prove that residual stress has significant effects on the stress behavior of mechanical parts. Therefore, the residual stress generated in the previous heat treatment step of casting must be taken into account in the stage of mechanical product design. Highlights The bigger compressive residual stress occurs, the closer surface. When the residual stress is close to plastic deformation, the stress by external load did not significantly change. The residual stress generated during the manufacturing process should be considered in the design stage.

EFFECT ON HARDNESS and MICRO STRUCTURAL BEHAVIOUR OF TOOL STEEL AFTER HEAT TREATMENT PROCESS

2017 ◽  
Vol 4 (24) ◽  
Author(s):  
Karanbir Singh ◽  
Aditya Chhabra ◽  
Vaibhav Kapoor ◽  
Vaibhav Kapoor
Keyword(s):  
Heat Treatment ◽  
Empirical Study ◽  
Tool Steel ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
Structural Behaviour ◽  
Treatment Processes ◽  
En 31

This study is conducted to analyze the effect on the Hardness and Micro Structural Behaviour of three Sample Grades of Tool Steel i.e. EN-31, EN-8, and D3 after Heat Treatment Processes Such As Annealing, Normalizing, and Hardening and Tempering. The purpose of Selecting Tool Steel is Because Tool Steel is Mostly Used in the Manufacturing Industry.This study is based upon the empirical study which means it is derived from experiment and observation rather than theory.

scholarly journals Mitigation of cylinder distortion in aluminum alloy engine blocks via heat treatment process optimization

2021 ◽  
Author(s):  
Anthony Lombardi
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Neutron Diffraction ◽  
Solution Heat Treatment ◽  
Treatment Process ◽  
Tensile Residual Stress ◽  
Engine Block ◽  
Engine Blocks ◽  
In Situ Neutron Diffraction

Lightweighting has become an important factor in the automotive industry due to stringent government regulations on fuel consumption and increased environmental awareness. Aluminum alloys are 65% lighter than cast iron enabling significant weight reduction. However, there are several significant challenges associated to the use of hypoeutectic Al-Si alloys in engine block applications. This dissertation investigated the factors influencing the susceptibility of in-service cylinder distortion as it is deleterious to engine operating efficiency, leading to environmental (increased carbon emissions) and economic (expensive recalls) repercussions. The initial segment of this dissertation sought to quantitatively confirm the cause of cylinder distortion by investigating distorted and undistorted service tested engine blocks. This analysis involved measurement of macro-distortion using a co-ordinate measuring machine, in-depth microstructural analysis, measurement of tensile properties, and residual stress mapping along the length of the cylinder bores (neutron diffraction). Upon determining the cause of distortion, the second phase of this project optimized the solution heat treatment parameters to mitigate future distortion in the engine blocks. This optimization was carried out by varying heat treatment parameters to maximize engine block strength. In addition, a pioneering application of in-situ neutron diffraction, along with a unique engine heating system, was used to develop a time-dependent correlation of residual stress relief during heat treatment, assisting in process optimization. The results indicate that the distorted engine block had high tensile residual stress, specifically at cylinder depths greater than 30 mm, while the undistorted block had mainly compressive stress. The maximum distortion occurred near the center portion of the cylinder (~60 mm), which had a combination of coarse microstructure (lower strength) and high tensile residual stress. As such,distortion can be prevented via maximization of strength and reduction in tensile residual stress. Lab scale castings and in-situ neutron diffraction were used to successfully develop an optimal heat treatment process to increase engine block integrity. These experiments found that solution heat treatment at 500 °C for 2 h increased tensile yield strength by 15-20% over engines produced using the current process. Furthermore, tensile residual stress was completely relieved by this heat treatment, reducing the susceptibility to in-service distortion. Solutionizing at temperatures above 500 °C was deemed unsuitable for engine block production due to incipient melting, which deteriorates strength.

Heat Treatment of Friction Surfaced Steel-Aluminum Couple

2015 ◽  
Vol 830-831 ◽  
pp. 135-138 ◽  
Author(s):  
K. Udaya Bhat ◽  
Nithin ◽  
Suma Bhat ◽  
Sudeendran
Keyword(s):  
Heat Treatment ◽  
Solid State ◽  
Mild Steel ◽  
Steel Surface ◽  
Aluminum Layer ◽  
Friction Surfacing ◽  
State Process ◽  
Aluminide Layer ◽  
Treatment Step ◽  
Heat Treatment Step

Friction surfacing is a solid state process and it is amenable for deposition of aluminum on steel. In this investigation, the mild steel surface was coated with a layer of aluminum using friction surfacing route. The aluminum thickness was in the range of 40-50 μm. It was followed by a heat treatment step to convert aluminum layer in to an aluminide layer. Heat treatment was done in open atmosphere at 700 °C for 2 hours. Microstuctural analysis showed that the aluminide layer is mainly made of Fe2Al5 and Fe4Al13, FeAl and Fe3Al are minor in fraction. Formation of Fe2Al5 is discussed. The aluminide layer also has some amount of porosities.

Research on Hot-Work Die Steel Used for Extrusion Wheel

2012 ◽  
Vol 482-484 ◽  
pp. 1611-1617
Author(s):  
Sheng Feng Wang ◽  
Hong Yu Liu ◽  
Peng Zhou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Fatigue ◽  
Treatment Process ◽  
Fatigue Tests ◽  
Heat Treatment Process ◽  
Die Steel ◽  
Die Steels ◽  
Treatment Processes ◽  
Hot Work Die

A set of new nitrogen-containing hot work die steels were designed. The best experimental steels and their heat treatment processes were optimized by microstructures, mechanical properties and thermal fatigue tests. The results show that the best compositions of V, Cr, N are 1.0 wt％, 3.75 wt％ and 0.01 wt％, respectively. The optimized heat treatment process is that quenching at 1080°C, first tempering at 550°C and second tempering at 530°C.

Numerical Simulation of Influences of Preheating and Postweld Heat Treatment in Welding

2012 ◽  
Vol 538-541 ◽  
pp. 1518-1521
Author(s):  
Qing Yang ◽  
Shu Jun Xie ◽  
Tian Bao Yu
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stress Distribution ◽  
Treatment Process ◽  
Postweld Heat Treatment ◽  
Element Model ◽  
Residual Stress Field ◽  
Pipe Welding ◽  
Postweld Heat ◽  
The Finite Element Model

In this paper, to investigative effects of preheating and postweld heat treatment on residual stress field in Q345 steel pipe welding, the finite element model was established. Preheating processes and postweld heat treatment process were simulated respectively. The results show that preheating can homogenize residual stress distribution of the weldment and decrease the residual stress. The heat treatment reduces the residual stress in inner and outer walls by 40% and 60% respectively and the stress distribution is more even and the stress concentration is reduced.

Reduction in transmission of hepatitis C after the introduction of a heat-treatment step in the production of C1-inhibitor concentrate

Transfusion ◽  
1995 ◽  
Vol 35 (3) ◽  
pp. 209-212 ◽  
Author(s):  
M. Cicardi ◽  
P. M. Mannucci ◽  
R. Castelli ◽  
M. G. Rumi ◽  
A. Agostoni
Keyword(s):  
Heat Treatment ◽  
Hepatitis C ◽  
C1 Inhibitor ◽  
Treatment Step ◽  
Heat Treatment Step

Microstructure and Tensile Ductility of a Ti-43Al-4Nb-1Mo-0.1B Alloy

2008 ◽  
Vol 1128 ◽  
Author(s):  
Laura M. Droessler ◽  
Thomas Schmoelzer ◽  
Wilfried Wallgram ◽  
Limei Cha ◽  
Gopal Das ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermodynamic Equilibrium ◽  
Room Temperature ◽  
Volume Fraction ◽  
Tensile Ductility ◽  
Heat Treatments ◽  
Air Cooling ◽  
B2 Phase ◽  
Treatment Step ◽  
Heat Treatment Step

AbstractThe microstructural development of a forged Ti-43Al-4Nb-1Mo-0.1B (in at%) alloy during two-step heat-treatments was investigated and its impact on the tensile ductility at room temperature was analyzed. The investigated material, a so-called TNM™ gamma alloy, solidifies via the β-route, exhibits an adjustable β/B2-phase volume fraction and can be forged under near conventional conditions. Post-forging heat-treatments can be applied to achieve moderate to near zero volume fractions of β/B2-phase allowing for a controlled adjustment of the mechanical properties. The first step of the heat-treatment minimizes the β/B2-phase and adjusts the size of the α-grains, which are a precursor to the lamellar γ/α2-colonies. However, due to air cooling after the first annealing step, the resulting microstructure is far from thermodynamic equilibrium. Therefore, a second heat-treatment step is conducted below the eutectoid temperature which brings the microstructural constituents closer to thermodynamic equilibrium. It was found that temperature and duration of the second heat-treatment step critically affect the solid-state phase transformations and, thus, control the plastic fracture strain at room temperature. Scanning and transmission electron microscopy studies as well as hardness tests have been conducted to characterize the multi-phase microstructure and to study its correlation to the observed room temperature ductility.

scholarly journals High Pressure Heat Treatment of AM Parts—Combining HIP and Heat Treatment

2019 ◽  
Author(s):  
Magnus Ahlfors
Keyword(s):  
Heat Treatment ◽  
Hot Isostatic Pressing ◽  
Vacuum Furnace ◽  
Creep Ductility ◽  
Post Process ◽  
Treatment Step ◽  
Hip Process ◽  
Heat Treatment Step ◽  
Defect Elimination ◽  
Metal Additive

Abstract Hot Isostatic Pressing (HIP) has been used for several decades within different industries for a wide variety of applications [1]. During the recent years HIP has become an important post process for metal additive manufacturing (AM) to secure material performance and quality. The HIP process uses a high isostatic pressure and elevated temperature to densify additively manufactured material by eliminating internal defects. The elimination of defects results in improved material properties such as fatigue, creep, ductility and fracture toughness [2-8]. HIP have historically been used only for densification and defect elimination and any modification and optimization of a material’s microstructure is usually performed after the HIP process in a separate heat treatment step in separate equipment e.g. a vacuum furnace. The main reason that these processes have been performed separately is that the achievable cooling rates in HIP systems have traditionally been relatively low, lower than what many materials require for heat treatment to for example create martensite or a super saturated condition.

scholarly journals Study of ALDH from Thermus thermophilus–Expression, Purification and Characterisation of the Non-Substrate Specific, Thermophilic Enzyme Displaying Both Dehydrogenase and Esterase Activity

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3535
Author(s):  
Kim Shortall ◽  
Edel Durack ◽  
Edmond Magner ◽  
Tewfik Soulimane
Keyword(s):  
Heat Treatment ◽  
Life Form ◽  
Thermus Thermophilus ◽  
Gel Filtration ◽  
Aldehyde Dehydrogenases ◽  
E Coli ◽  
Ability To Act ◽  
High Yields ◽  
Treatment Step ◽  
Heat Treatment Step

Aldehyde dehydrogenases (ALDH), found in all kingdoms of life, form a superfamily of enzymes that primarily catalyse the oxidation of aldehydes to form carboxylic acid products, while utilising the cofactor NAD(P)+. Some superfamily members can also act as esterases using p-nitrophenyl esters as substrates. The ALDHTt from Thermus thermophilus was recombinantly expressed in E. coli and purified to obtain high yields (approximately 15–20 mg/L) and purity utilising an efficient heat treatment step coupled with IMAC and gel filtration chromatography. The use of the heat treatment step proved critical, in its absence decreased yield of 40% was observed. Characterisation of the thermophilic ALDHTt led to optimum enzymatic working conditions of 50 °C, and a pH of 8. ALDHTt possesses dual enzymatic activity, with the ability to act as a dehydrogenase and an esterase. ALDHTt possesses broad substrate specificity, displaying activity for a range of aldehydes, most notably hexanal and the synthetic dialdehyde, terephthalaldehyde. Interestingly, para-substituted benzaldehydes could be processed efficiently, but ortho-substitution resulted in no catalytic activity. Similarly, ALDHTt displayed activity for two different esterase substrates, p-nitrophenyl acetate and p-nitrophenyl butyrate, but with activities of 22.9 and 8.9%, respectively, compared to the activity towards hexanal.

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