Failure Analysis and Study on Heat Treatment Process of Grate Bars Used in Sintering Trolley

2014 ◽  
Vol 1061-1062 ◽  
pp. 454-459
Author(s):  
An Min Li ◽  
Ding Ma ◽  
Qi Feng Zheng ◽  
Ruo Huai Chen ◽  
Qiang Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Residual Austenite ◽  
Shrinkage Porosity ◽  
Heat Treatment Process ◽  
Fracture Characteristics ◽  
Heat Treated ◽  
Primary Means ◽  
Optimum Heat ◽  
Optimum Heat Treatment

The as-cast grate bar structure used in sintering trolley is primarily comprised of austenite and eutectic (eutectic austenite and eutectic carbide).The austenite is dendrite, while the carbides are reticular and chrysanthemum-like. The failed grate bar structure primarily consists of ferrite, carbide, martensite and residual austenite; cavity shrinkage and shrinkage porosity exist in the structure, and the fracture exhibits typical cleavage fracture characteristics. The primary means of failure are abrasion and fracture. The secondary carbides precipitated in the sample (quenching (1050°C+2.5h)+ tempering (390°C+2.5h)) and the other one (quenching (1050°C+2.5h)+ tempering (420°C+2.5h) ) are dispersed and refined. Compared with the as-cast one, their relative abrasion resistance performances respectively are 0.8645 and 0.8752.The values of hardness and impact toughness of the samples heat-treated are greater than those of the as-cast grate bar. The optimum heat treatment process is as follows: quenching (1050°C,2.5h) + tempering (390°C~420°C,2.5h)

scholarly journals Effect of Heat Treatments on Microstructural Evolution and Tensile Properties of 15Cr12MoVWN Ferritic/Martensitic Steel

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1271
Author(s):  
Tingwei Ma ◽  
Xianchao Hao ◽  
Ping Wang
Keyword(s):  
Heat Treatment ◽  
Tensile Properties ◽  
Room Temperature ◽  
Treatment Process ◽  
Martensitic Steel ◽  
Heat Treatment Process ◽  
Lath Width ◽  
Optimum Heat ◽  
Martensitic Lath ◽  
Optimum Heat Treatment

In this study, the phase transformation temperature of 15Cr12MoVWN ferritic/martensitic steel was determined by differential scanning calorimetry to provide a theoretical basis for the design of a heat treatment process. An orthogonal design experiment was performed to investigate the relationship between microstructure and heat treatment parameters, i.e., normalizing temperature, cooling method and tempering temperature by evaluating the room-temperature and elevated-temperature tensile properties, and the optimum heat treatment parameters were determined. It is shown that the optimized heat treatment process was composed of normalizing at 1050 °C followed by air cooling to room temperature and tempering at 700 °C. Under the optimum heat treatment condition, the room-temperature tensile properties were 1014 MPa (UTS), 810.5 MPa (YS) and 18.8% (elongation), while the values are 577.5 MPa (UTS), 469 MPa (YS) and 39.8% (elongation) tested at 550 °C. The microstructural examination shows that the strengthening contributions from microstructural factors were the martensitic lath width, dislocations, M23C6, MX and grain boundaries of prior austenite grain (PAG) in a descending order. The main factors influencing the tensile strength of 15Cr12MoVWN steel were the martensitic lath width and dislocations.

scholarly journals Hardness and Conductivity of Die Forged ZYK530 Magnesium Alloy

2021 ◽  
Author(s):  
Fenghong CAO ◽  
Yaohui XU ◽  
Chang CHEN ◽  
Zhaohui QIN ◽  
Chi DENG
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Treatment Process ◽  
Mg Alloy ◽  
Heat Treatment Process ◽  
Optimum Heat ◽  
The Relationship ◽  
Optimum Heat Treatment ◽  
Good Agreement ◽  
Peak Value

The relationship among the microstructure, hardness and electrical conductivity of the as-forged ZYK530 Mg alloy after heat treatment was analyzed and studied using a microscope, X-Ray Diffractometer, eddy current conductivity meter, and Vickers microhardness tester, to explore optimum heat treatment process of ZYK530 Mg alloy. The results show that: with the prolongation of holding time, the electrical conductivity and microhardness show the same change trend, both of which show an oscillatory upward trend, and then decrease in an oscillatory downward trend after reaching the  peak value. There is a linear positive correlation between the conductivity and the hardness, and the fitting results of the conductivity and hardness are in good agreement with the measured results; combined with the actual production, when the heat-treatment is 480 ℃ × 8 h + 220 ℃ × 3 h, the highest hardness is 79.2 HV, the electroconductivity is 36.2%IACS, and the comprehensive performance is the best, which is the best heat treatment process.

Numerical Simulation of the H-Beam during Cooling Process

2013 ◽  
Vol 310 ◽  
pp. 145-149 ◽  
Author(s):  
Jian Liu ◽  
Fu Zeng Hou ◽  
Xiao Guang Yu
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Heat Treatment ◽  
Theoretical Basis ◽  
Treatment Process ◽  
Residual Austenite ◽  
Heat Treatment Process ◽  
Cooling Process ◽  
Controlled Cooling ◽  
H Beam

In order to improve the comprehensive mechanical properties of the steel, the heat treatment software COSMAP is used to simulate the rolling and controlled cooling of H-beam. The numerical simulation shows that the mechanical properties of controlled cooling can be obviously improved, when the cooling rate is controlled at 10°C/s around. Strength and hardness can be improved under the condition of ductility and toughness ensured. Meanwhile the amount of residual austenite can be reduced significantly. It provides a theoretical basis for further optimization of the heat treatment process.

High Tensile Strength of Drawn Gold

2005 ◽  
Vol 495-497 ◽  
pp. 907-912 ◽  
Author(s):  
Suk Hoon Kang ◽  
Hee Suk Jung ◽  
Woong Ho Bang ◽  
Jae Hyung Cho ◽  
Kyu Hwan Oh ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Treatment Process ◽  
Gold Wire ◽  
Equivalent Strain ◽  
Heat Treatment Process ◽  
High Tensile Strength ◽  
Heat Treated ◽  
Gold Wires

This paper studies the microstructure of drawn gold wires to equivalent strain of 10 and to equivalent strain of 8.5 then heat-treated. The texture of gold wire drawn to strain of 10 is mainly composed of <100> and <111> fibers. Tensile strength of the gold wire increases with <111> fiber fraction, while the grain size does not appear to affect the tensile property. With an exception at heat treatment at 600oC, the texture of gold wire drawn the strain of 8.5 is replaced with <100> fiber component by heat treatment process at 400~700oC. Heat treatment at 600oC produces <110> fiber or <112> fiber, depending upon annealing time.

Casting and Heat Treatment of Turbocharger Impellers Thixocast from Alloy 201

2012 ◽  
Vol 192-193 ◽  
pp. 556-561 ◽  
Author(s):  
Qiang Zhu ◽  
Stephen Midson ◽  
Chang Wei Ming ◽  
Helen V. Atkinson
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
Heat Treatment Condition ◽  
Hot Tearing ◽  
Alloy Casting ◽  
Heat Treated ◽  
Before And After ◽  
Optimum Heat ◽  
Semi Solid ◽  
Optimum Heat Treatment

Commercial semi-solid cast impellers are produced from Al-Si-Cu alloys heat treated to the T6 temper. The study described in this paper involved the identification of casting and heat treatment parameters to produce semi-solid processed turbocharger impellers from a silicon-free, higher strength 201 alloy. Casting parameters were identified which minimized hot tearing in the alloy 201 impellers. A series of heat treatment studies were performed to determine optimum heat treatment parameters. The T71 temper was identified as the preferred heat treatment condition to produce high strength as well as superior elongation. The results from mechanical property measurements conducted on the T71 heat treated impellers are reported. Optical and scanning electron microscopy (SEM) were also used to characterize the microstructure of alloy 201 impellers before and after heat treatment, and representative microstructures are presented.

Microstructure of Silicon Nitride Fibers at Elevated Temperatures

2017 ◽  
Vol 898 ◽  
pp. 1705-1711 ◽  
Author(s):  
Jun Zhe Li ◽  
Xun Sun ◽  
Hai Tao Liu ◽  
Hai Feng Cheng ◽  
Xiao Shan Zhang
Keyword(s):  
Heat Treatment ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Treatment Process ◽  
Elevated Temperatures ◽  
Heat Treatment Process ◽  
Amorphous Silicon Nitride ◽  
Heat Treated ◽  
Strength Retention ◽  
Heat Treated Temperature

The composition and microstructure of silicon nitride fibers after heat-treatment at elevated temperatures were investigated by XRD, NMR, XPS, SEM and TEM analyses. The results show that as-received fibers consisted of amorphous silicon nitride, and a little Si-C-O structure. During heat-treatment process, α-Si3N4 and β-Si3N4 formed resulting from the crystallization of amorphous silicon nitride, and the formation of β-SiC derived from the decomposition of Si-C-O structure. As heat-treated temperature increased from 1400oC to 1600oC, the above phenomenon become obvious, indicating that the fiber would possess high serving life with serving temperature lower than 1400oC. The tensile strength of fibers stays stable when heat-treated temperature was below 1200oC, while the strength retention of fibers sharply decreased to 50% after heat-treatment at 1400°C.

scholarly journals Optimisation of Heat Treatment Process for Damping Properties of Mg-13Gd-4Y-2Zn-0.5Zr Magnesium Alloy Using Box–Behnken Design Method

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 157 ◽  
Author(s):  
Jun Zhang ◽  
Ziming Kou ◽  
Yaqin Yang ◽  
Baocheng Li ◽  
Xiaowen Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Treatment Process ◽  
High Strength ◽  
Damping Capacity ◽  
Heat Treatment Process ◽  
Damping Properties ◽  
Heat Treated ◽  
Second Phases ◽  
Imagej Software

High damping magnesium alloys have poor mechanical properties, so it is necessary to investigate the damping properties of high-strength wrought magnesium alloys to effectively reduce vibration and noise in mechanical engineering. The aim of this work is to improve the mechanical damping performance of a novel high-strength Mg-13Gd-4Y-2Zn-0.5Zr magnesium alloy by optimising the heat treatment process. The mechanical damping coefficient, considering not only damping capacity but also the yield strength, is selected as one of the evaluation indexes. The other evaluation index is the tensile strength. The solid solution and ageing treatment were optimised by Box-Behnken method, an efficient experimental design technique. Heat treatment experiments based on the optimal parameters verified that the best process is a solution at 520 °C for 10 h followed by ageing at 239 °C for 22 h. The damping coefficient reaches 0.296, which is 73.1% higher than that before heat treatment. There was a good agreement between the experimental and Box-Behnken predicted results. The microstructure, morphology and composition of the second phases after heat treatment were analysed by SEM, XRD and EDS. Due to the high content of alloying elements in Mg-13Gd-4Y-2Zn-0.5Zr alloy, there are a large number of second phases after heat treated. They mainly include layer, short rod-shaped, bulk long period stacking order (LPSO) Mg12YZn and granular Mg5Gd phases. It was found that the area fraction of the second phases has an extreme effect on the damping capacity and short rod-shaped LPSO can effectively improve the damping capacity of heat-treated Mg-13Gd-4Y-2Zn-0.5Zr alloy. The volume fraction of the second phases was analysed by ImageJ software. It was concluded that the smaller the area occupied by the second phases, the better the mobility of the dislocation, and the better the damping performance of the alloy. The statistical analysis results obtained using ImageJ software are consistent with the experimental results damping capacity.

Numerical Simulation of the I-Beam during Cooling Process

2013 ◽  
Vol 712-715 ◽  
pp. 1634-1637
Author(s):  
Jian Liu ◽  
Fu Zeng Hou ◽  
Xiao Guang Yu
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Heat Treatment ◽  
Cooling Rate ◽  
Theoretical Basis ◽  
Treatment Process ◽  
Residual Austenite ◽  
Heat Treatment Process ◽  
Cooling Process ◽  
Controlled Cooling

In order to improve the comprehensive mechanical properties of the steel, the heat treatment software COSMAP is used to simulate the rolling and controlled cooling of I-beam. The numerical simulation shows that: when the cooling rate is controlled at 10 °C/s around, the mechanical properties of controlled cooling can be obviously improved. The strength and hardness can be improved on the condition of ductility and toughness ensured, while the amount of residual austenite can be reduced significantly, which provide a theoretical basis for further optimization of the heat treatment process.

scholarly journals Effect of Heat Treatment on Microstructure and Mechanical Properties of a Selective Laser Melting Processed Ni-Based Superalloy GTD222

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3668
Author(s):  
Tian Xia ◽  
Rui Wang ◽  
Zhongnan Bi ◽  
Guoliang Zhu ◽  
Qingbiao Tan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
Laser Melting ◽  
Microstructure Characteristics ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated

Additive manufacturing (AM) of nickel-based superalloys is of high interest for application in complex hot end parts. However, it has been widely suggested that the microstructure-properties of the additive manufacturing processed superalloys are not yet fully clear. In this study, the GTD222, an important superalloy for high-temperature hot-end part, were prepared using selective laser melting and then subjected to heat treatment. The microstructure evolution of the GTD222 was investigated and the mechanical properties of heat treated GTD222 were tested. The results have shown that the grain size of the heat treated GTD222 was close to its as-built counterparts. Meanwhile, a large amount of γ’ and nano-scaled carbides were precipitated in the heat treated GTD222. The microstructure characteristics implied that the higher strength of the heat treated GTD222 can be attributed to the γ’ and nano-scaled carbides. This study provides essential microstructure and mechanical properties information for optimizing the heat treatment process of the AM processed GTD222.

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