scholarly journals Impact of Molybdenum on Heat-Treatment and Microstructure of ADI

2018 ◽  
Vol 925 ◽  
pp. 188-195 ◽  
Author(s):  
Julius Alexander Gogolin ◽  
Babette Tonn

Austempered Ductile Iron (ADI) is characterized by high tensile strength with acceptable ductility. Steel, as a large competitor to ADI, also meets the tensile and yield strength. Nevertheless, the main advantages of ADI compared to steel are the lower density (7.2 g/cm3 to 7.85 7.87 g/cm3) for weight reduction and lower manufacturing costs because of less energy consumption during the production. One of the main problems of producing ADI is the quenching process during heat treatment of thick-walled castings. The inner part of a massive casting – in contrast to the outer part – cools down more slowly, resulting in a heterogeneous microstructure with parts of pearlite and ferrite embedded in austenite before reaching the isothermal transformation temperature. Molybdenum is, besides nickel, copper and manganese, one of the possible alloying elements that postpone the transition point of ferrite and/or pearlite. To investigate the influence of molybdenum in thick-walled castings experiments with different molybdenum contents were performed. In dependence on the molybdenum content, different austenisation and ausferritisation temperatures and times are examined in order to investigate the transformation points, fraction and morphology of different phases. The mechanism of molybdenum in ADI has been investigated by means of dilatometer tests, microstructure analysis and mechanical tests.

2005 ◽  
Vol 495-497 ◽  
pp. 907-912 ◽  
Author(s):  
Suk Hoon Kang ◽  
Hee Suk Jung ◽  
Woong Ho Bang ◽  
Jae Hyung Cho ◽  
Kyu Hwan Oh ◽  
...  

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.


2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Muideen Bodude ◽  
Oluwole D Adigun ◽  
Ahmed Ibrahim

AISI 1018 mild steels are widely used for engineering applications in machine components and for structural purposes. These materials suffer mechanical damages especially when used under critical conditions of extreme load. In this study, the effect of austempering heat-treatment on the hardness, tensile strength, impact energy and the microstructure of AISI 1018 steels were evaluated. The steel specimens were subjected to austempering heat-treatment by austenitizing at a temperature of 830°C, maintained at this temperature for a period of 1 hour 30 minutes, before rapidly cooled down in a NaNO3 salt bath maintained at 300°C for isothermal transformation for a further 50 minutes before finally cooled down to room temperature. Microstructural analysis using Scanning Electron Microscope (SEM) shows transformation from ferrite/pearlite to bainite microstructure. The tensile strengths of the specimen increased from 400 MPa to 500 Mpa; hardness increased from an average value of 140Rc to 162Rc; while impact energy increased from 15.6 Joule to 30.6 Joule by the austempering heat-treatment. Keywords—Austempering, hardness, tensile strength, impact energy, microstructure


2014 ◽  
Vol 622-623 ◽  
pp. 1075-1080 ◽  
Author(s):  
Kota Sakumoto ◽  
Kazuhiko Yamazaki ◽  
Takashi Kobayashi ◽  
Shinsuke Suzuki

We investigated punching properties (crack in punched surface and hole expansion ratio) of high tensile strength steel sheets with and without center segregation. High strength steel sheets were heat-treated to reduce center segregation. Tensile strength, shear surface ratio, depth of rollover and burr height were measured on heat-treated steel sheets to confirm the effect of heat-treatment on strength. The EPMA analysis showed that the center segregation of Mn was reduced by the diffusion during heat-treatment. Crack-formation frequency and hole expansion ratio were also measured. As a result, the center segregation of Mn in high tensile strength steel sheets decreased by the heat-treatment (600 oC for 100 h) with maintaining the tensile strength, the depth of rollover and the burr height. The crack-formation frequency of the steel sheets decreased through heat-treatments.


Making adobes with the best mechanical properties for the construction of earthen housings is the overall goal of this work. Specifically, we study the influence of rice straw on the physical and mechanical properties of these adobes. The physical and mechanical properties (compressive and flexural strength) of adobes (mixture of sandy clay and rice straw) have been studied with different proportions of straw in the mixture. It is a question of determining the quantity of stalks of rice straw making it possible to optimize the mechanical performances of the composite. Various compositions have been considered with mass concentrations of rice straw ranging from 0 to 40% relative to the volume of clay sand to make 4×4×16cm prismatic specimens. The results obtained during physical and mechanical tests were presented in the form of a graph. The analysis of these data shows that the optimal addition of rice straw in the clay matrix is 25% for a better compromise between the compressive and tensile strengths. The improvement of the physical and mechanical properties of adobes is related to the good adhesion between the rice straw and the clay matrix, to the high tensile strength of the rice straw and finally to a good distribution of cracks in the composites


Alloy Digest ◽  
2000 ◽  
Vol 49 (2) ◽  

Abstract Type 301 (UNS S30100) is an austenitic chromium-nickel stainless steel capable of attaining high tensile strength and ductility by cold working. It is not hardenable by heat treatment. Type 301 is essentially nonmagnetic in the annealed condition and becomes magnetic with cold deformation. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-775. Producer or source: J & L Specialty Steel Inc.


2018 ◽  
Vol 876 ◽  
pp. 36-40
Author(s):  
Yustiasih Purwaningrum ◽  
Dwi Darmawan ◽  
Panji Lukman Tirta Kusuma

Heat treatment of T-Joint’s steel arc welded are performed are investigated in this research. The heat treatment process that used were annealing and quenching. The microstructure was investigated by optical microscope. The mechanical behavior of the samples was investigated using universal tensile testing machine for tensile test and Microvickers hardness method for hardness testing. The microstructure of welding zone of welding metals with various heat treatments is grain boundary ferrite, Widmanstatten ferrite and acicular ferrite. The weld metal with quenching treatment has a highest tensile strength with tensile strength 197.97 Mpa. The quenching process increases the tensile strength by 49.58 %. The distortion value in weld metal without heat treatment, quenching and annealing is 0.11mm; 0.04 mm and 0.08 mm respectively. The hardness number of weld metals with quenching process have a highest number base metal, HAZ and weld metals. Results showed that the mechanical properties of T-joints steel arc welded can be improved by various heat treatments.


2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Abdullahi O Adebayo ◽  
Gabriel L Taiwo ◽  
Akinlabi Oyetunji

The effects of magnesium variation and austempering heat treatment on mechanical and microstructural properties of ductile iron produced using the rotary furnace were investigated. Varied quantity of magnesium-ferrosilicon in the range of 0.03 % to 0.06 % were used as nodulirizer to treat 4 kg mass of molten metal per ladle by sandwich process and poured into sand mould.  Mechanical test (tensile, hardness, fatigue, impact and wear) and micro-structural examinations were carried out on the four samples produced. Samples C and D of 0.056% and 0.061% magnesium showed an improvement in their micro-structural properties due to the presence of more graphite nodules. Hence, they were observed to have exhibited better tensile strength of 598.07MPa and 609.03MPa. The fatigue strength also increased to 501.91MPa and 509.27MPa respectively. These two samples were further subjected to austempering heat treatment by heating to 850ºC for austenitization and soaked for homogenization for one hour at the temperature before quickly transferred into a salt bath of 50 % NaNO3 : 50 % NaCl maintained at 3600C and quenched for transformation for 1 hour before finally air cooled. Mechanical tests and micro-structural examinations were thereafter carried out. Sample C had an outstanding increase in tensile strength, from 598.07MPa to 891.22MPa, while specimen D increased from 609.03MPa to 898.76MPa. The results of abrasion test indicated that samples C and D had abrasion resistance increase from 2.20×10¹¹m² and 2.39×10¹¹m² to 2.35×10¹¹m² and 2.68×10¹¹ m² respectively after austempering. There were also relative increase in fatigue resistance and impact toughness for the two samples but with relative reduction in hardness from 47.7 to 44.2 and 50.3 to 47.4.


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