Investigation of Influence of Quenching and Annealing on the Plane Fracture Toughness and Brittle to Ductile Transition Temperature of the Zinc Coated Structural Steel Materials

2017 ◽  
Vol 5 (2) ◽  
pp. 33-42
Author(s):  
M. Ramesh ◽  
Rajnish Garg ◽  
Garimella V. Subrahmanyam
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Transition Temperature ◽  
Structural Steel ◽  
Water Quenching ◽  
Time Interval ◽  
Brittle To Ductile Transition ◽  
Treatment Processes ◽  
Specific Temperature

This article discusses that the variation in fracture toughness is exclusively due to the influence of coating on the surface of the material, depending upon the time interval that the specimen is immersed in the coating tub under a specific temperature. Parameters during the process of coating have shown their own influence on heat treatment, which has shown its own significance of the fracture toughness of coated and uncoated materials. Hence, to estimate this effect, EN 18 and AISI 1020 steels have been tested under different heat treatment processes, like annealing, oil-quenching and water-quenching. The results obtained under these conditions have clearly shown that the influence of heat treatment is significant on the fracture toughness of the materials. Compared to untreated materials, the annealed and quenched materials have shown much variation in fracture toughness.

scholarly journals A New Method for Determining the Brittle-to-Ductile Transition Temperature of a TiAl Intermetallic

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1550
Author(s):  
Sarper Nizamoglu ◽  
Karl-Heinz Lang ◽  
Stefan Guth ◽  
Martin Heilmaier
Keyword(s):  
Transition Temperature ◽  
Charpy Impact ◽  
Plastic Strain Amplitude ◽  
Bending Tests ◽  
Brittle To Ductile Transition ◽  
Intermetallic Materials ◽  
Different Temperatures ◽  
Specific Temperature ◽  
Increasing Temperature ◽  
Fully Lamellar

Intermetallic materials typically change their deformation behavior from brittle to ductile at a certain temperature called the Brittle-to-Ductile Transition Temperature (BDTT). This specific temperature can be determined by the Charpy impact, tensile or bending tests conducted at different temperatures and strain rates, which usually requires a large number of specimens. In order to reduce the number of necessary specimens for finding the BDTT, a new methodology comprising cyclic loadings as the crucial step was studied on a fully lamellar TiAl alloy with composition Ti-48Al-2Nb-0.7Cr-0.3Si. The loading blocks are applied isothermally under strain control and repeated on the same specimen at different temperatures. The development of plastic strain amplitude with increasing temperature is analyzed to determine the BDTT of the specimen. The BDTTs found with the described method agree well with literature data derived with conventional methods. With the loading strategy presented in this study, the BDTT and additionally the effect of strain rate on it can be found by using a single specimen.

Variables Affecting Fracture Toughness of Welds in T-K-Y Connections

2014 ◽  
Author(s):  
Radhika Panday ◽  
Shenjia Zhang ◽  
Jon Ogborn ◽  
Badri K. Narayanan
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Transition Temperature ◽  
Weld Metal ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Factors Affecting ◽  
Brittle Transition ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition

Fracture toughness of tubular welded joints is one of the critical factors affecting the structural integrity and reliability of offshore structures, such as platforms and subsea pipelines. The factors affecting the design fracture toughness of these structures are related to, both, the welding process as well as the chemical composition of the weld metal. The welding process in this application typically comprises of depositing weld metal in the tubular joints of varying thicknesses through series of weld passes. The number of weld passes required for welding these joints subjects the weld metal to repetitive cycles of heating and cooling. The effect of the thermal cycling introduces significant heterogeneity in the microstructure. This is further exacerbated by the presence of micro-alloying elements such as Niobium (Nb) and Vanadium (V) that form complex carbides, nitrides and carbo-nitrides during post weld heat treatment (PWHT). The focus of this work is to evaluate the effect of micro-alloying elements on the ductile to brittle transition temperature and the mode of fracture at temperatures relevant to offshore applications. A threshold Nb and V level has been determined for achieving acceptable weld metal toughness. The improvement in the fracture toughness using this approach has been quantified by Charpy V-Notch (CVN) and Crack Tip Opening Displacement (CTOD) measurements. The Ductile to Brittle Transition Temperature (DBTT) has been shown to be shifted to lower temperatures by 25 °C after post weld heat treatment in the welds where the total amount of Nb and V are controlled to less than 40 ppm. A wet precipitate extraction technique was used to extract precipitates from the welds to establish the presence of fine Nb rich precipitates in the welds with the higher DBTT. The weld deposited with controlled levels of Nb and V was further tested in different joint configurations and base plate thickness. The fracture toughness was evaluated by CTOD testing of the weld in two different thicknesses (50 mm and 70 mm). Increased specimen thickness resulted in lower CTOD values.

Application of Master Curve Method to Fracture Toughness Estimation of the Transport and Storage Cask Material

2008 ◽  
Author(s):  
Kiminobu Hojo ◽  
Kentaro Yoshimoto ◽  
Ryuichi Yamamoto ◽  
Toshihiro Matsuoka ◽  
Uwe Mayer
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Alloy Steel ◽  
Master Curve ◽  
Structural Integrity ◽  
Scale Model ◽  
Low Alloy Steel ◽  
Brittle To Ductile Transition ◽  
Data Scatter ◽  
And Storage

The transportation and storage casks have to be designed by considering transport and handling accidents. IAEA safety standard [1] requires drop test using a scale model and demonstration of structural integrity of the cask container vessel from the view point of leakage and instable fracture. For the fracture evaluation, it has to be verified that brittle fracture does not occur at the lowest temperature −40degC. MHI has developed the MSF-57BG cask whose body is made of forged low alloy steel LF3-m. It is well known that low alloy steel has the brittle-to-ductile transition temperature range of fracture toughness and large scatter of toughness value in this region. For the cask’s integrity evaluation, it is needed to obtain the fracture toughness dependent on temperature of this material by considering data scatter. The Master curve procedure [2] was proposed for estimation of fracture toughness of the pressure vessel on the basis of statistical procedure by using relatively small number of specimens. This paper examined the determination method of fracture toughness considering dynamic loading effect and data scatter in the brittle-to-ductile transition temperature by using the Master curve procedure.

Effects of Hot Working and Heat Treatment on Properties of Ti-62A Alloy Plate

2012 ◽  
Vol 567 ◽  
pp. 112-115
Author(s):  
Rui Liu ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Yang Yu ◽  
Yan Yan Fu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Titanium Alloy ◽  
Large Range ◽  
Alloy Plate ◽  
Thick Plates ◽  
Treatment Processes ◽  
Comprehensive Properties ◽  
Heat Treated ◽  
Final Rolling

A titanium alloy with the composition of Ti-Al-Sn-Zr-Mo-V-Si-Cr, named Ti-62A alloy, were rolled into thick plates by four different routes, followed by solution heat treated and aging treated. Effects of various rolling routes and heat treatment processes on tensile properties, fracture toughness and resistance to fatigue crack growth were investigated. The results reveal that a rolling heats above β-transus before final rolling pass is helpful to improve comprehensive properties. The properties of Ti-62A alloy can be adjusted in a large range depending on heat treatment.

High Temperature Fracture Toughness in Silicon Nitride and Sialon

1993 ◽  
Vol 115 (3) ◽  
pp. 268-272 ◽  
Author(s):  
Y. Mutoh ◽  
N. Miyahara ◽  
K. Yamaishi ◽  
T. Oikawa
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Transition Temperature ◽  
Silicon Nitride ◽  
Glass Phase ◽  
Temperature Transition ◽  
Brittle To Ductile Transition ◽  
Temperature Fracture ◽  
Increasing Temperature ◽  
Sintered Silicon

Fracture Toughness of HIP-sintered silicon nitride decreased with increasing temperature up to 1200°C. The brittle-to-ductile transition was observed in the temperature range from 1200°C to 1275°C: the fracture toughness rapidly increased in the transition region. Above the transition temperature, the fracture toughness decreased with increasing temperature. Fracture toughness of sialon increased with increasing temperature. Transition of fracture mechanism was observed in sialon around 1300°C. The differences of temperature dependence of fracture toughness between two materials are interpreted in terms of the effects of grain-boundary glass phase on fracture.

Effect of Prestraining on the Brittle-To-Ductile Transition of NiAl Single Crystals

1996 ◽  
Vol 460 ◽  
Author(s):  
S. Shrivastava ◽  
F. Ebrahimi
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Crack Initiation ◽  
Single Crystals ◽  
Low Temperatures ◽  
Crack Initiation And Propagation ◽  
Brittle To Ductile Transition ◽  
Initiation And Propagation ◽  
Toughness Testing ◽  
Dislocation Sources

ABSTRACTThe brittle-to-ductile transition (BDT) has been established for NiAl single crystals as evaluated by fracture toughness testing and also the effects of prestraining on the brittle-to-ductile transition temperature (BDTT) have been investigated. Specimens were prestrained to a 10% plastic strain level at 200°C under tension prior to toughness testing. The BDT of the prestrained specimens was compared to that of the as homogenized specimens. The results have revealed the occurrence of two competing effects upon prestraining: (1) an increase in dislocation sources causing a difficulty in micro-crack initiation and resulting in an increase in toughness at low temperatures, and (2) an increase in the flow stress resulting in an increase in BDT temperature. The crack initiation and propagation mechanisms were also analyzed and have been discussed.

Microstructural and Mechanical Development of As-Cast and Heat-Treated 935AgCu Alloys

2017 ◽  
Vol 891 ◽  
pp. 389-394
Author(s):  
Siriwan Sakultanchareonchai ◽  
Torranin Chairuangsri ◽  
S. Imurai ◽  
Ekasit Nisaratanaporn
Keyword(s):  
Heat Treatment ◽  
Aging Treatment ◽  
Water Quenching ◽  
Homogenization Treatment ◽  
Copper Addition ◽  
Treatment Processes ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Modulus Of Resilience ◽  
20 Nm

Microstructural and mechanical development of the various heat-treated 935 Ag-Cu alloys were explored. The heat-treatment processes were applied viz. holding before quenching for 2 and 15 min, homogenization at 750 °C for 60 min followed by water quenching, and aging at 350 °C for 15 to 60 min followed by water quench. It was found that the specimens with copper addition gave a high resiliency in all heat treatment conditions however the effect of homogenization with aging treatment fostered deep blemish or fire scale on its surface. The amplifications of resiliency of 935 heat-treated AgCuSn and AgCuBe alloy were increased but elongation values were slightly reduced. The 935 AgCuBeSn specimens produced adequate resiliency and elongation after aging at 350 °C for 15 to 60 min followed by water quenching. Partial dissolution and spheroidization of eutectic phase were occurred by homogenization treatment at 750 °C. Aging treatment promoted precipitation of 3-20 nm fcc (Cu,Sn)–rich precipitates and engendered an improvement of hardness, yield strength and the modulus of resilience or resiliency.

Simulation of the Heat Treatment of an Automotive Cast Part

2010 ◽  
Author(s):  
Patrice Lasne ◽  
Mickael Barbelet ◽  
Olivier Jaouen ◽  
Frederic Costes ◽  
Ihab Ragai ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Distribution ◽  
Isothermal Transformation ◽  
Shrinkage Porosity ◽  
Hot Tearing ◽  
Water Quenching ◽  
Dump Truck ◽  
Cast Part ◽  
Treatment Processes ◽  
Isothermal Transformation Diagram

In this paper, simulation of the casting and heat treatment processes of front spindle of a rigid dump truck are presented. The objectives are to present how the different operations can be simulated in order to predict the local phases in the different areas of the part. To reach these objectives, two software packages are used in sequenced. The first one, Thercast, is used to simulate the casting operation. The second one, Forge, is applied to the water-quenching simulation. The general formulations used are shortly presented in this paper. The aim of casting simulation is to compute the metal behavior from the liquid state at the pouring stage to the solid state during cooling into the mold. Filling and cooling phases simulations, taking into account the air gap, ensure that no internal defects like shrinkage, porosity, micro porosity or hot tearing are taking place into the part. Forge software allows the water quenching stage simulation. A model is used to deduct the IT diagram (Isothermal Transformation diagram) from the material composition. The initial grain size influences the transformation kinetics. Another main phenomenon is the efficiency of the cooling bath. The results of the simulation (phase distribution, distortion, residual stresses) strongly depend on these input conditions. Thus, the effect of input data variations on final results must be studied. The modeling approach is validated by comparisons with micrographic observations. Another solution to determine the reliability of the models is to observe the local properties in the quenched part. The prediction of the local micro hardness can be used to evaluate the accuracy of the quenching models.

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