The significant impact of introducing nanosize precipitates and decreased effective grain size on retention of high toughness of simulated heat affected zone (HAZ)

2020 ◽  
pp. 140484
Author(s):  
J. Wang ◽  
Y.F. Shen ◽  
W.Y. Xue ◽  
N. Jia ◽  
R.D.K. Misra
Keyword(s):  
Grain Size ◽  
Heat Affected Zone ◽  
High Toughness ◽  
Effective Grain Size ◽  
Nanosize Precipitates

scholarly journals Effective grain size and charpy impact properties of high-toughness X70 pipeline steels

2005 ◽  
Vol 36 (8) ◽  
pp. 2107-2114 ◽  
Author(s):  
Byoungchul Hwang ◽  
Yang Gon Kim ◽  
Sunghak Lee ◽  
Young Min Kim ◽  
Nack J. Kim ◽  
...  
Keyword(s):  
Grain Size ◽  
Charpy Impact ◽  
Pipeline Steels ◽  
Impact Properties ◽  
High Toughness ◽  
Effective Grain Size

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

Effect of Post Weld Heat Treatment on Fusion and Heat Affected Zone Microstructure and Mechanical Properties of Inconel X-750 Welds

2011 ◽  
Vol 214 ◽  
pp. 108-112 ◽  
Author(s):  
Prachya Peasura ◽  
Bovornchok Poopat
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Weld Metal ◽  
Heat Affected Zone ◽  
Aging Temperature ◽  
Post Weld Heat Treatment ◽  
High Aging Temperature ◽  
Zone Microstructure

The Inconel X-750 indicates good hot corrosion resistance, high stability and strength at high temperatures and for this reason the alloy is used in manufacturing of gas turbine hot components. The objective of this research was study the effect of post weld heat treatment (PWHT) on fusion zone and heat affected zone microstructure and mechanical properties of Inconel X-750 weld. After welding, samples were solutionized at 1500 0C. Various aging temperature and times were studied. The results show that aging temperature and time during PWHT can greatly affect microstructure and hardness in fusion zone and heat affected zone. As high aging temperature was used, the grain size also increased and M23C6 at the grain boundary decreased. This can result in decreased of hardness. Moreover excessive aging temperature can result in increasing MC carbide intensity in parent phase (austenite). It can also be observed that M23C6 at the grain boundary decreased due to high aging temperature. This resulted in decreasing of hardness of weld metal and heat affected zone. Experimental results showed that the aging temperature 705 0C aging time of 24 hours provided smaller grain size, suitable size and intensity of MC carbide resulting in higher hardness both in weld metal and HAZ.

scholarly journals Influence of Welding Parameters On Grain Size, Haz and Degree of Dilution in 6063-t5 Alloy. Optimisation Through the Taguchi Method of the Gmaw Welding Process.

2022 ◽  
Author(s):  
Jose Luis Meseguer Valdenebro ◽  
Eusebio José Martínez Conesa ◽  
Antonio Portoles
Keyword(s):  
Grain Size ◽  
Taguchi Method ◽  
Heat Affected Zone ◽  
Welding Process ◽  
Welding Parameter ◽  
Welding Parameters ◽  
Taguchi’S Method ◽  
Gmaw Welding ◽  
Made In

Abstract The aim of this work is to carry out the design of experiments that determine the influence of the welding parameters using Taguchi’s method on the grain size, HAZ, and the degree of dilution in 6063-T5 alloy. The welding process used is GMAW and the welding parameters are power, welding speed and bevel spacing. The study of the influence of the welding parameters on the measurements made in the welding (which are the size of heat affected zone, the degree of dilution, and the grain size) allows one to determine the quality of the joint . In addition, the welding parameter most influential in minimising the three measurements will be determined.

scholarly journals The Effect of Lath Martensite Microstructures on the Strength of Medium-Carbon Low-Alloy Steel

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 232 ◽  
Author(s):  
Chen Sun ◽  
Paixian Fu ◽  
Hongwei Liu ◽  
Hanghang Liu ◽  
Ningyu Du ◽  
...  
Keyword(s):  
Grain Size ◽  
Carbon Content ◽  
Lath Martensite ◽  
Block Size ◽  
Martensitic Steels ◽  
Austenite Grain Size ◽  
Medium Carbon ◽  
Transmission Electron ◽  
Lath Width ◽  
Effective Grain Size

Different austenitizing temperatures were used to obtain medium-carbon low-alloy (MCLA) martensitic steels with different lath martensite microstructures. The hierarchical microstructures of lath martensite were investigated by optical microscopy (OM), electron backscattering diffraction (EBSD), and transmission electron microscopy (TEM). The results show that with increasing the austenitizing temperature, the prior austenite grain size and block size increased, while the lath width decreased. Further, the yield strength and tensile strength increased due to the enhancement of the grain boundary strengthening. The fitting results reveal that only the relationship between lath width and strength followed the Hall–Petch formula of. Hence, we propose that lath width acts as the effective grain size (EGS) of strength in MCLA steel. In addition, the carbon content had a significant effect on the EGS of martensitic strength. In steels with lower carbon content, block size acted as the EGS, while, in steels with higher carbon content, the EGS changed to lath width. The effect of the Cottrell atmosphere around boundaries may be responsible for this change.

Dissipation Pattern of Excess Pore Pressure After Liquefaction in Saturated Sand Deposits

2003 ◽  
Vol 1821 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Ik Soo Ha ◽  
Young Ho Park ◽  
Myoung Mo Kim
Keyword(s):  
Grain Size ◽  
Pore Pressure ◽  
Dynamic Loading ◽  
Time History ◽  
Excess Pore Pressure ◽  
Pore Pressures ◽  
Dissipation Pattern ◽  
Effective Grain Size ◽  
Coefficient Of Uniformity ◽  
Excess Pore

In liquefied areas, the amount of damage to a structure is mainly affected by the postliquefaction behavior of the liquefied ground. Understanding postliquefaction behavior requires understanding the dissipation pattern of excess pore pressure after liquefaction. It is difficult to measure pore pressures generated and dissipated during an earthquake because of the more-or-less randomness of earthquake events. Researchers have artificially generated liquefaction with sand samples in the laboratory and have simulated curves for the time history dissipation of excess pore pressure. To estimate variation in permeability during dynamic loading, which should be known for settlement predictions of the ground undergoing liquefaction, 1-g shaking table tests were carried out on five kinds of sands, all with high liquefaction potentials. During tests, excess pore pressures at various depths and surface settlements were measured. The measured curve of the excess pore pressure dissipation was simulated using the solidification theory. From analysis of the velocity of dissipation, the dissipation pattern of excess pore pressure after liquefaction was examined. Permeability during dissipation was calculated using the measured settlement and dissipation velocity, also used for estimating permeability during dynamic loading. The dissipation velocity of excess pore pressure after liquefaction had a linear correlation with the effective grain size divided by the coefficient of uniformity. The increase in the ground’s initial relative density played a role in shifting this correlation curve toward increased dissipation velocity. Permeability during liquefaction increased 1.4 to 5 times compared with the permeability of the original ground, the increase becoming greater as the effective grain size of the test sand increased and the coefficient of uniformity decreased.

The Effect of the Erbium Content on the Microstructure and Mechanical Property of 6061 Aluminum Alloys

2017 ◽  
Vol 898 ◽  
pp. 35-40 ◽  
Author(s):  
Wen Jian Lv ◽  
Bo Long Li ◽  
Peng Qi ◽  
Zuo Ren Nie
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloys ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Size Refinement ◽  
Effective Grain Size ◽  
Different Content ◽  
Microstructure And Mechanical Property

The 6061 aluminum alloys with different content of erbium were prepared. The erbium content was optimized by measurement of grain refining effects and tensile strength. After solid solution treatment of the alloy with optimized erbium content at 505 °C ~ 595 °C for 4 h. and then ageing at –160 °C ~ 200 °C for 3 h., the grain size decreased with the content of erbium, achieving the most effective grain size refinement at the erbium content of 0.15wt.%. The tensile strength of as-cast alloy could reach up to 243 MPa at the erbium content of 0.15%. -Combined with the microstructures and mechanical properties, the erbium content of 0.15% was the optimized content, and heat treatments of ageing at 180 °C for 3 h. followed by solid solution at 565 °C for 4 h were suggested.

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