scholarly journals Age Hardening in COR-Ten Steel

2019 ◽  
Vol 9 (2) ◽  
pp. 3001-3004
Keyword(s):  
Atmospheric Corrosion ◽  
Solution Treatment ◽  
Protective Layer ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Age Hardening ◽  
Accelerated Cooling ◽  
Ice Fog ◽  
Corrosive Effect ◽  
Quenched Steel

Weathering steels developed under the name COR-TEN steels, established themselves as a promising material to meet the demand for atmospheric corrosion resistance and eliminate the need for painting. COR-TEN steel is resistant to corrosive effect of weather such as rain, snow, ice, fog, etc. A coating of dark brown oxidation is developed over the metal surface, when it comes in contact with the environment thereby inhibiting the deeper penetration and negating the need for painting and reducing the rust-prevention cost over the years. Thus the steel is allowed to rust which forms a protective layer and slows down the rate of corrosion. The present study emphasizes the age hardening behavior of COR-TEN steel. The steel was subjected to solution treatment at 1000°C following accelerated cooling with water, oil and air. The oil quenched steel was then subjected to aging treatment at 400°C and 500°C for various times ranging from 5 min to 1500 min followed by water quenching. In order to ascertain the response to aging hardness measurement were conducted by employing a load of 20 Kgf. Metallographic examinations were also conducted to study the resulting structural transformations in various stages of investigations.

scholarly journals Effect of Ti Addition to Age Hardening Response of Al-10Zn-6MgxTi Alloy Produced by Squeeze Casting

2018 ◽  
Vol 186 ◽  
pp. 02009
Author(s):  
Dwi Ayu Nurcahyaningsih ◽  
Risly Wijanarko ◽  
Irene Angela ◽  
Bondan Tiara Sofyan
Keyword(s):  
Squeeze Casting ◽  
Solution Treatment ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hardness Measurement ◽  
Impact Testing ◽  
Age Hardening ◽  
Peak Hardness ◽  
7Xxx Alloy ◽  
Ti Addition

This research focused on investigating the effects of Ti addition on the age hardening response of Al 7xxx alloy for Organic Rankine Cycle (ORC) turbine impeller application in power plant generators. Al-10Zn-6Mg wt. % alloys were produced by squeeze casting with 0.02, 0.05, and 0.25 wt. % Ti addition. As-cast samples were homogenized at 400 °C for 4 h. Solution treatment was conducted at 440 °C for 1 h, followed by quenching and ageing at 130 °C for 200 h. Age hardening result was observed using Rockwell B hardness measurement. Other characterizations included impact testing, STA, optical microscopy, and SEM-EDS. Results showed that the addition of Ti in all content variations increased the as-cast hardness due to the diminution of secondary dendrite arm spacing (SDAS) values of the alloy. Ageing at 130 °C strengthened the alloys, however the addition of Ti was not found to affect neither peak hardness nor impact values of the alloy. Identities of second phases formed during solidification were found to be T (Mg32(Al,Zn)49), β (Al8Mg5), and TiAl3, while precipitates produced during ageing were GP Zone, η′, and η (MgZn2).

Age-Hardening Characteristics of Cu-3Ag-0.5Zr Alloy

2012 ◽  
Vol 710 ◽  
pp. 563-568 ◽  
Author(s):  
S. Chenna Krishna ◽  
K. Thomas Tharian ◽  
Bhanu Pant ◽  
Ravi S. Kottada
Keyword(s):  
Electrical Conductivity ◽  
Rocket Engine ◽  
Copper Alloys ◽  
Solution Treatment ◽  
Aging Treatment ◽  
High Strength ◽  
Average Diameter ◽  
Age Hardening ◽  
Liquid Rocket

Among the copper alloys, the Cu-3Ag-0.5Zr alloy is one of the potential candidates for combustion chamber of liquid rocket engine because of its optimum combination of high strength with thermal conductivity. The present study is a detailed characterization of microstructure, strength, and electrical conductivity during the aging treatment. The aging cycle for Cu-3Ag-0.5Zr alloy after the solution treatment (ST) was optimized to obtain higher hardness without compromising on electrical conductivity. The precipitates responsible for strengthening in aged samples are identified as nanocrystalline Ag precipitates with an average diameter of 9.0±2.0 nm.

Microstructure and Aging Behavior in AM60 Magnesium Alloy Cast into Sand and Permanent Molds

2010 ◽  
Vol 654-656 ◽  
pp. 679-682 ◽  
Author(s):  
Hiroshi Yamada ◽  
Mitsuaki Furui ◽  
Susumu Ikeno ◽  
Yukio Sanpei ◽  
Katsuya Sakakibara ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Aging Temperature ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Age Hardening ◽  
Cellular Precipitation ◽  
Lower Aging Temperature ◽  
Peak Aging ◽  
Alloy Castings ◽  
Hardening Curve

AM60 magnesium alloy castings gave the solution treatment at 688K for 86.4ks. After that, aging treatment was carried out at three temperatures of 473, 498 and 523K. The age hardening curve obtained, hardness of all the specimens in the condition of peak aging was increased by decreasing the aging temperature. In the condition of long aging time, a cellular precipitation grows up from grain boundary to crystal grain. Fine cellular precipitation and intergranular precipitation obviously occurs at the lower aging temperature.

Aging Behavior of Al-Li-Cu-Mg Alloy Processed by High-Pressure Torsion

2010 ◽  
Vol 654-656 ◽  
pp. 1243-1246 ◽  
Author(s):  
Seung Won Lee ◽  
Daichi Akama ◽  
Z. Horita ◽  
Tetsuya Masuda ◽  
Shoichi Hirosawa ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Rolling Process ◽  
Mg Alloy ◽  
Age Hardening ◽  
Subsequent Aging ◽  
Solid Solution Treatment ◽  
Conventional Rolling

This study presents an application of high-pressure torsion (HPT) to an Al-Li-Cu-Mg alloy (2091). The alloy was subjected to solid solution treatment at 505oC for 30 minutes and was processed by HPT under 6 GPa for 5 revolutions at room temperature. The hardness increased with straining and saturated to a constant level at 225 Hv. Aging was undertaken on the HPT-processed alloy at 100, 150 and 190oC for the total periods up to 9.3 days. The aging treatment led to a further increase in the hardness to ~275 Hv. It is shown that the simultaneous strengthening of the alloy due to grain refinement and age hardening was successfully achieved by application of HPT and subsequent aging treatment. The enhancement of the strength is prominent when compared with the application of a conventional rolling process.

Influence of Yttrium and Heat Treatment on Microstructure and Mechanical Properties of AM60 Alloy

2011 ◽  
Vol 194-196 ◽  
pp. 1319-1325
Author(s):  
Zheng Tian ◽  
Zhan Yi Cao ◽  
Jian Meng
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Yield Strength ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
X Ray ◽  
Solid Solution Treatment ◽  
Yttrium Addition

The effect of yttrium addition and heat treatment on the mechanical properties and microstructure of AM60 magnesium alloy have been investigated using X-ray phase analysis, microstructure investigation, tensile test, hardness measurement and fracture surfaces analysis. The results showed that the mechanical properties of the alloys were obviously improved with the addition of yttrium no more than 1.0%. The reinforcement of the alloys resulted from the appearance of Al2Y phase. After solid-solution treatment (T4), the Mg17Al12 phase almost dissolved in Mg matrix, but the rare earth compounds Al2Y phase was rather stable. The ultimate tensile strength σb was improved, but the yield strength σ0.2 and elongation δ were only slightly changed. After solid-solution + aging treatment (T6), the Mg17Al12 phase precipitated again and their morphology was changed. The yield strength σ0.2 was improved.

Analyzing Si Precipitation on Age Hardening of an Al-Si-Mg Cast Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 1685-1689
Author(s):  
Gui Qing Wang ◽  
Yan Liu ◽  
Guo Cheng Ren ◽  
Zhong Kui Zhao
Keyword(s):  
Cast Alloy ◽  
Solution Treatment ◽  
Hardness Measurement ◽  
Mg Alloy ◽  
Age Hardening ◽  
Micro Hardness ◽  
Tem Analysis ◽  
Cast Sample ◽  
Transmission Electron ◽  
Cast Condition

The correlation of age hardening behavior and Si precipitation in α(Al) of Al-8wt%Si-0.35wt%Mg alloy has been investigated by micro hardness measurement, electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) analysis. The EPMA results show that Si concentration in the center of α (Al) dendrites is higher than that in the edge and the main concentration is about 1.5wt% for Al-8wt%Si-0.35wt%Mg alloy in as cast condition. After solution treatment at 530 °C for 8 h followed by water quenching (T4 treatment), hardness value decreases 9 HV, which is accompanied by the decrease of Si concentration in α (Al). Aging the as-cast sample and T4 treatment sample at 150 °C for 20 h, the main concentration of Mg and Si in α (Al) changes little. Hardness value after as-cast aging is only 3 HV lower than that after T6 treatment. Nanometer Si particles and β″ and/or β′ phases are found in aged samples. The higher hardness value for as-cast aging samples should contribute to the nanometer Si particles in α (Al).

Two-Step Aging Behaviour of Solution Treated A356 System Alloy

2018 ◽  
Vol 941 ◽  
pp. 1083-1087
Author(s):  
Masahiko Iijima ◽  
Tomoya Ozasa ◽  
Susumu Ikeno ◽  
Kenji Matsuda ◽  
Seiji Saikawa
Keyword(s):  
Solution Treatment ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Mg Alloy ◽  
Peak Hardness ◽  
System Alloy ◽  
Solution Treated ◽  
Heat Treated ◽  
Final Aging ◽  
Positive Effect

Al-7mass%Si-0.3mass%Mg alloy is widely applied to the automotive components, such as road wheel or suspension frame because of having higher ductility and corrosion resistance. Two-step aging behavior of solution treated Al-7mass%Si-0.3mass%Mg system alloy A356 cast into permanent mold and solution treated was investigated by micro-vickers hardness measurement, optical microscopy (OM) and transmission electron microscopy (TEM). The microstructure of as-cast state was consist of primary crystallized α-Al and secondary crystallized eutectic phases. Al-7mass%Si-0.3mass%Mg alloy after casting, the test specimens were heat treated for different pre-aging temperatures at 273K, 348K and 423K for various times after solution treatment at 813K for 36ks. After pre-aging treatment, the test specimens were heat treated for artificial aging at 523K for various times. The peak hardness increased almost the same value when the pre-aging temperature was 273K. On the other hands, positive effect of the final-aging was occurred after pre-aging at 348K and 423K with significantly increasing hardness in the under-aging region. The fine precipitates were observed in the specimen which was final aging at 523K after pre-aging at 348K and 423K.Such a positive effect is considered due to the influence of precipitated phase mainly such as clusters and /or G.P.zone.The present study aims to investigate the effect of pre-aged temperature on final-aged behavior in A356 system alloy.

Analyzing Age Hardening Behaviors of an Al-Si-Mg Cast Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 3945-3948
Author(s):  
Ying Zhou ◽  
Gui Qing Wang
Keyword(s):  
Cast Alloy ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Age Hardening ◽  
Permanent Mold ◽  
Scanning Calorimetry ◽  
Electron Probe Micro Analyzer ◽  
Transmission Electron ◽  
Measurement Results ◽  
Dsc Analyses

The age hardening process for permanent mold samples of Al-7Si-0.3Mg cast alloy has been investigated by hardness measurement, differential scanning calorimetry (DSC), transmission electron microscope (TEM) and electron probe micro analyzer (EPMA). Age hardening results show that the age hardening response of Al-7Si-0.3Mg alloy is independent on cooling rate. There is a hardness value decrease about 10 HV after T4 treatment. Hardness value after as-cast aging at 150 °C for 20 h is just a little smaller than that after T6 treatment for permanent mold samples. The precipitation behaviors during T6 treatment and as cast aging treatment have been analyzed by DSC analyses. The hardness measurement results have been discussed by analyzing the precipitation behaviors and the Mg and Si concentration in α (Al).

Microstructure and Properties of Cu-3.2Ni-0.75Si-0.3Zn Alloy for Lead Frame

2007 ◽  
Vol 26-28 ◽  
pp. 569-572 ◽  
Author(s):  
Yi Zhang ◽  
Ping Liu ◽  
Bao Hong Tian ◽  
D.M. Zhao ◽  
Shu Guo Jia ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Age Hardening ◽  
Lead Frame ◽  
Transformation Kinetics ◽  
Transmission Electron ◽  
Resistance Variation ◽  
Electrical Resistance Variation ◽  
Means Of Transmission

The effect of aging temperature and aging time on properties of Cu-3.2Ni-0.75Si-0.3Zn alloy were studied. The alloys were isochronally or isothermally aged after solution treatment. The cold rolling prior to the aging treatment was used to increase the precipitation rate .The microstructure of the alloy was studied by means of transmission electron microscope (TEM). The results show that the fine and dispersed precipitates are fully coherent with the Cu matrix and make the alloy possesses higher hardness and conductivity after the alloy was solution at 1173K and then aged at different time. The precipitates responsible for the age-hardening effect was Ni2Si.The transformation kinetics were studied by analyzing the electrical resistance variation of the solution Cu-3.2Ni-0.75Si-0.3Zn alloy in the process of aging.

Intragranular and Grain Boundary Precipitations with Aging Treatment in Mg-Al System Alloys Poured into Gravity Mold

2012 ◽  
Vol 706-709 ◽  
pp. 1140-1145
Author(s):  
Mitsuaki Furui ◽  
Susumu Ikeno ◽  
Seiji Saikawa
Keyword(s):  
Aluminum Content ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Age Hardening ◽  
Precipitation Reaction ◽  
Az91 Magnesium Alloy ◽  
Continuous Precipitation ◽  
Microstructure Observation ◽  
Transmission Electron ◽  
Az91 Magnesium

It is well-known that age hardening occurs in Mg-Al system alloys, when the alloy containing aluminum exceeds 6mass%. This precipitation reaction depends on aluminum content and aging temperature. The aging behavior in AZ91 magnesium alloy was investigated and it is the subject of this paper. However, for the Mg-Al system alloys, the influence of aluminum content on aging hardening characteristics has not been researched in detail so far. In this study, continuous and discontinuous precipitations during aging in Mg-Al system alloys cast into sand and iron molds were investigated by means of hardness measurement and microstructure observation with optical microscopy and transmission electron microscopy. Variation of hardness with aging was found to be caused mainly by the discontinuous precipitation along the grain boundaries from the composite rule in hardness. In iron mold castings, It was found that the variation of hardness with aging was found to be caused mainly by the continuous precipitation inside the crystal grain.

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