scholarly journals Development of New Cobalt-Free Maraging Steel with Superior Mechanical Properties via Electro-Pulsing Technology

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1299
Author(s):  
Dong Pan ◽  
Yuguang Zhao ◽  
Yitong Wang ◽  
Xiaofeng Xu ◽  
Xueying Chong
Keyword(s):  
Mechanical Properties ◽  
Maraging Steel ◽  
Aging Treatment ◽  
High Energy ◽  
Cooling Condition ◽  
Air Cooling ◽  
Water Cooling ◽  
Initial State ◽  
Reverted Austenite ◽  
Superior Mechanical Properties

The ductility of cobalt-free maraging steel is unsatisfactory because of the high content of Ti. Traditional heat treatment can not effectively improve the ductility of this kind steel. In this contribution, high-energy electro-pulsing is adopted in a T250 steel to solve this problem efficiently. It is found that the EPS treatment (electro-pulsing treatment under water-cooling condition) can accelerate the formation of retained austenite and nano stacking faults. Meanwhile, the microstructure is also refined by EPS treatment. Then, taking the EPS sample as the initial state, nano-reverted austenite combined with finer η-Ni3Ti precipitates are formed during EPA treatment (electro-pulsing treatment under air-cooling condition), compared with TA (traditional aging) treatment. The results of mechanical properties indicate that the strength and elongation are both enhanced by electro-pulsing treatment. Consequently, the electro-pulsing treatment can be a promising technology to devise cobalt-free maraging steel with better properties.

scholarly journals Effects of solution and aging treatment parameters on the microstructure evolution of Ti–10V–2Fe–3Al alloy

2020 ◽  
Vol 39 (1) ◽  
pp. 501-509
Author(s):  
Wan-Liang Zhang ◽  
Wen-Tao Hao ◽  
Wei Xiong ◽  
Guo-Zheng Quan ◽  
Jiang Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aging Temperature ◽  
Treatment Process ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Solution Temperature ◽  
Air Cooling ◽  
Water Cooling ◽  
Β Phase ◽  
Aging Conditions

AbstractThe solution-aging treatment parameters, including solution temperature, cooling rate and aging temperature, have significant influences on the microstructures and comprehensive mechanical properties of titanium alloy. In this work, the detailed microevolution behaviors of Ti–10V–2Fe–3Al alloy under different solution and aging conditions have been investigated through a series of heat-treatment experiments. The results of solution-treatment experiments reveal that the content of αp-phase is reduced to zero as the solution temperature is raised to a certain α → β critical transformation point. Recrystallized β-grains can be observed at the solution temperature of 820°C. In addition, the cooling way (air cooling or water cooling) has little influence on the microevolution behaviors for this alloy during the solution-treatment process. As for the solution-aging-treatment experiments, the results reveal that αs-phases are precipitated from the supersaturated β-phase, and the fraction of αs-phase increases with increasing aging temperature. However, the precipitated α-grains intend to coalesce and coarsen as the aging temperature raises above 510°C. Therefore, the advocated solution-aging-treatment program is solution treatment at 820°C with air cooling followed by aging treatment at 510°C with air cooling.

Study on Metallography Test of the Steel SPV490 for Atmospheric Storage Tank After Fire

2016 ◽  
Author(s):  
Zhou Fang ◽  
Weiwei Hu ◽  
Deyu Liu ◽  
Guanghai Li ◽  
Zhe Wang
Keyword(s):  
Mechanical Properties ◽  
Working Conditions ◽  
Storage Tank ◽  
High Strength ◽  
Air Cooling ◽  
Microscopic Structure ◽  
Water Cooling ◽  
Storage Tanks ◽  
Fire Temperature ◽  
Optical Microstructure

The fire process was simulated by the heat treatment to the Steel SPV490 of atmospheric storage tank, thereby obtaining the metal specimens in different fire temperature, holding time, and cooling modes. And as the temperature increases, the microscopic structure of Steel SPV490 changes under different working conditions, which could be shown in optical microstructure pictures after doing the interception, inlay, polishing, finishing to the specimens. The result shows that, the mechanical properties of the Steel SPV490 for storage tank changes as the temperature rising from the microscopic view. Nodulizing of the cementite in pearlite occurs, and the strength decreases when the high strength steel SPV490 of large atmospheric storage tanks under air cooling condition below 700 °C, however, it equivalents to the normalizing process, as the sorbite occurs in the steel, and the strength increases a bit when the temperature is above 900 °C. The water-cooling of steel SPV490 above 900 °C equivalents to the process of quenching. The occurrence of martensitic substantially increases the strength and the brittleness, and the elongation decreases rapidly.

Effect of Cooling Condition on Microstructure and Mechanical Properties in Large Line Energy Welded Joints of Ultra-Fine Grained Steel

2011 ◽  
Vol 189-193 ◽  
pp. 3345-3350 ◽  
Author(s):  
Hong Yun Zhao ◽  
Li Zhou ◽  
Bo Chen ◽  
Guo Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Cooling Condition ◽  
Water Cooling ◽  
Line Energy ◽  
Fine Grained ◽  
Heavy Plate ◽  
Microstructure And Mechanical Properties

The medium and heavy plate of 800 MPa grade ultra-fine grained steel was welded by CO2 gas shielded welding using large line energy. The effect of cooling condition on microstructure and mechanical properties of welded joints was investigated. The results showed that the cases about significant grain size increasing and strength decreasing do exist in the heat affected zone of large line energy welded joints of 800 MPa grade ultra-fine grained steel. Grain growth and softening in the heat affected zone could be suppressed effectively by water cooling in the course of welding. The mechanical properties of welded joints could be significantly increased by water cooling, and the process of CO2 gas shielded welding under water cooling is practical for joining ultra-fine grained steel using large line energy.

scholarly journals Nanocrystalline Materials: Synthesis, Characterization, Properties, and Applications

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1317
Author(s):  
Amanendra K. Kushwaha ◽  
Merbin John ◽  
Manoranjan Misra ◽  
Pradeep L. Menezes
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Chemical Vapor ◽  
Chemical Precipitation ◽  
High Energy ◽  
Synthesis Methods ◽  
Materials Synthesis ◽  
Current State ◽  
Superior Mechanical Properties ◽  
Energy Ball

Nanostructuring is a commonly employed method of obtaining superior mechanical properties in metals and alloys. Compared to conventional polycrystalline counterparts, nanostructuring can provide remarkable improvements in yield strength, toughness, fatigue life, corrosion resistance, and hardness, which is attributed to the nano grain size. In this review paper, the current state-of-the-art of synthesis methods of nanocrystalline (NC) materials such as rapid solidification, chemical precipitation, chemical vapor deposition, and mechanical alloying, including high-energy ball milling (HEBM) and cryomilling was elucidated. More specifically, the effect of various process parameters on mechanical properties and microstructural features were explained for a broad range of engineering materials. This study also explains the mechanism of grain strengthening using the Hall-Petch relation and illustrates the effects of post-processing on the grain size and subsequently their properties. This review also reports the applications, challenges, and future scope for the NC materials.

scholarly journals Effect of high temperature and type of cooling on some mechanical properties of cement mortar

2018 ◽  
Vol 162 ◽  
pp. 02010
Author(s):  
Faisal Abdulhussei ◽  
Waleed Abbas ◽  
Qais Frayyeh
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Construction Materials ◽  
Air Cooling ◽  
Water Cooling ◽  
Crushed Brick

Mortar of cement as construction materials subjected sometimes to high temperature. Some of properties of this mortar being studied after this effect. The effect of high temperature 100, 200, 400 and 700°C (exposed for two hrs.) on some mechanical properties (compressive and flexural strength) of two groups of cement mortar samples (with and without the addition of crushed bricks and superplasticizer as modifying materials) has been studied. Two methods of cooling samples by air and by water for 1/2 hr. was used, then tested after 3, 7 and 28 days. The results showed that the compressive and flexural strength for reference mix exposed to 700°C and water cooling decreased by 65.3 % and 64.7%, respectively, compared with their reference mix tested at 20°C in 28 days. While mixes containing 100% of crushed brick as an additive and air cooling decreases by 12.3% and 9% of their compressive and flexural strength, respectively compared with the mixes tested at 20°C in 28 days. Also showed that the decreases in flexural strength for no sand mixes containing 100% of crushed brick and 4% of superplasticizer exposed to 700°C and then water cooling was 28.2% compared to those for reference mixes tested at 20°C.

The Effect of Heat Treatment on Microstructure and Mechanical Properties of Ti-8.5Nb-4.5Ta-13Zr Alloy

2017 ◽  
Vol 899 ◽  
pp. 389-394
Author(s):  
Narayanna Marques Ferreira Mendes ◽  
Marcio W.D. Mendes ◽  
Ana Helena de Almeida Bressiani ◽  
Hidetoshi Takiishi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Vacuum ◽  
Beta Phase ◽  
High Energy ◽  
Alpha Phase ◽  
Phase Region ◽  
Planetary Mill ◽  
Air Cooling ◽  
13Zr Alloy

The effects of the heat treatment on the phase transformations, microstructures and mechanical properties of Ti-8.5Nb-4.5Ta-13Zr alloy were studies in this work. Some of the starting powder were obtained by hydrogenation method and homogenized with metallic tantalum in a high-energy planetary mill. The samples were compacted in a uniaxial and cold isostatic presses and then, sintered at 1150 °C for 10 hours under high vacuum. The heat treatments were carried out at the same sintering temperature, above the α / β transus, at different cooling rates such as furnace cooling, air cooling and water quenching. The sintered samples were characterized using the Archimedes density method, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microhardness was measured using the Vickers indentation (ASTM E384-11 Standard). It was shown that the microstructure of Ti-8.5Nb-4.5Ta-13Zr alloy consists of beta-phase matrix and alpha-phase region of two structures: equiaxed and needle-like grains also known as Widmanstätten structure. The precipitation of the alpha-phase in the beta-phase matrix led to an increase in Vickers microhardness of the alloy which was furnace cooled. Moreover, a few remaining pores were still found and density above 98% was achieved.

Microstructure and Mechanical Properties of 22MnB5 Steel with Different Cooling Method

2013 ◽  
Vol 331 ◽  
pp. 555-558 ◽  
Author(s):  
Hong Wei Liu ◽  
Jing Bo Yu ◽  
Hong Yun Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Volume Fraction ◽  
Air Cooling ◽  
Water Cooling ◽  
Cooling Method ◽  
22Mnb5 Steel ◽  
Microstructure And Mechanical Properties ◽  
Result Show ◽  
Cooling Speed

Microstructure and mechanical properties of 22MnB5 Steel were analysis with different cooling method. The result show that the volume fraction of martensite in 22MnB5 is increased with the rising of cooling speed, the microstructure with air cooling is composed of ferrite and pealite, and the quenched microstructure is 100% martensite with metal die cooling and water cooling, tensile strength increased with the rising of cooling speed. The highest tensile strength is 1569.60MPa with elongation only 2.13% with water cooling method.

Effect of 0.06%Nb on the Microstructure and Mechanical Properties of Mn-Series Low Carbon Air-Cooling Bainitic Steels

2011 ◽  
Vol 284-286 ◽  
pp. 1191-1195
Author(s):  
Chun Feng ◽  
Bing Zhe Bai ◽  
Yan Kang Zheng
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Granular Bainite ◽  
Air Cooling ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties ◽  
Bainitic Steels ◽  
Superior Mechanical Properties ◽  
Allotriomorphic Ferrite ◽  
Strength Improvement

The effect of 0.06%Nb on the microstructure and mechanical properties of grain boundary allotriomorphic ferrite (FGBA) / granular bainite (Bg) air-cooling bainitic steels has been investigated in this paper. The results indicate that the steel acquires superior mechanical properties by adding 0.06%Nb. Compared with Non-Nb steel, the addition of 0.06%Nb increases the tensile strength and yield strength about 37.1% (From 780MPa to 1070MPa)and 26.6%(From 557MPa to 705MPa) respectively, remaining 18.3% elongation and 97J toughness. The addition of 0.06%Nb not only promotes the nucleation of intragranular ferrite but also refines the allotriomorphic ferrite grain , both of which in turn contribute to the refinement of granular bainite cluster including its ferrite platelets and M-A islands. Under the synthetic roles of the microstructure refinement and precipitation strengthening, 148MPa yield strength improvement has been acquired in the low carbon air-cooling bainitic steel by the adding of 0.06%Nb.

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