Precipitation Behavior of a Maraging Stainless Steel

2012 ◽  
Vol 567 ◽  
pp. 92-95 ◽  
Author(s):  
Yue Jiang ◽  
Ying Ying Ai ◽  
Qi Ting Wang

The changes of precipitation phases and matrix structures in Fe-13Cr-7Ni-4Mo-4Co-2W maraging stainless steel at different temperature were studied by using the Thermo-Calc software. The research was on the microstructures and precipitation behaviors of the maraging stainless steel, the performance is investigated through solution and aging treatment by TEMand SADP. The calculation results were in good agreement with the experiments, which demonstrated that when maraging stainless steel was treated in high temperature, the Laves-Fe2Mo precipitates became totally dissolved as the temperature was above 1050°C, and about 8% of R phase was found during aging. The calculation provides a guiding significant to the establishment of reasonable heat treatment process and the development of new materials.

2012 ◽  
Vol 507 ◽  
pp. 127-133 ◽  
Author(s):  
Sigrid Seuss ◽  
Tayyab Subhani ◽  
Min Yi Kang ◽  
Kenji Okudaira ◽  
Isaac E. Aguilar Ventura ◽  
...  

Electrophoretic deposition (EPD) has been successfully used to deposit composite coatings composed of polyetheretherketone (PEEK) and titanium dioxide (TiO2) nanoparticles on 316L stainless steel substrates. The suspensions of TiO2 nanoparticles and PEEK microparticles for EPD were prepared in ethanol. PEEK-TiO2 composite coatings were optimized using suspensions containing 6wt% PEEK-TiO2 in ethanol with a 3:1 ratio of PEEK to TiO2 in weight and by applying a potential difference of 30 V for 1 minute. A heat-treatment process of the optimized PEEK-TiO2 composite coatings was performed at 335°C for 30 minutes with a heating rate of 10°Cminto densify the deposits. The EPD coatings were microstructurally evaluated by scanning electron microscopy (SEM). It was demonstrated that EPD is a convenient and rapid method to fabricate PEEK/TiO2 coatings on stainless steel which are interesting for biomedical applications.


2013 ◽  
Vol 845 ◽  
pp. 408-411
Author(s):  
M.S. Adenan ◽  
M.N. Berhan ◽  
E. Haruman

An approach has been made in developing hybrid heat treatment process for improvement of surface properties of duplex stainless steel (DSS). The process was performed using horizontal tube furnace at temperature of 450° C at holding time of 4, 8, 16 and 30 hours. Carbon and nitrogen elements were simultaneously introduced onto the surface of DSS with a ratio of 5% CH4 + 25% NH3 + 70% N2. The microstructure, phase analysis, surface hardness and hardness profile were systematically assessed. Hybrid heat treatment process managed to produce diffusional layer, where longer holding time had increased the thickness of the layer and improved the surface hardness. Expanded austenite phase has been formed at specimens 8, 16 and 30 hours. Longer holding time however gradually diffused Cr2N at the ferrite grains at the substrates. From the process, it can be concluded that low temperature hybrid heat treatment be able to improve the surface hardness of DSS however concern on holding time must be highly considered.


2012 ◽  
Vol 706-709 ◽  
pp. 1580-1585
Author(s):  
Hai Liang Yu ◽  
Jin Wu Kang ◽  
Tian You Huang

Blades are key part of hydro turbines, which often distorts during heat treatment process for their special structures. In this paper, thermal fluid finite element simulation of the forced air cooling process of a blade casting was carried out under a variety of distances between fans and blades, air speeds, groups of fans and circumstance temperatures. The temperature fields of blade castings were obtained. A novel parameter, temperature difference between surfaces of castings along thickness direction, was proposed to analyze the distortion of blade castings. The distortion behavior of blade castings with martensitic stainless steel were discussed, which is in good agreement with distortion regularity of the experimental ones. The temperature differences between blade casting surfaces are always greater than zero, resulting in distortion which could be divided into three stages. Finally, we focused on discussing the control methods of distortion behavior of blade castings which could be operated in actual production.


2021 ◽  
Author(s):  
Fenghong CAO ◽  
Yaohui XU ◽  
Chang CHEN ◽  
Zhaohui QIN ◽  
Chi DENG

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.


2013 ◽  
Vol 820 ◽  
pp. 15-19
Author(s):  
Xiao Dong Du ◽  
Zi Li Song ◽  
Yi Qing Chen ◽  
Jia Qing Wang ◽  
Guang Fu Liu ◽  
...  

This paper describes the influence of heat treatment process on the microstructure and properties of a new martensitic stainless steel, which contains 0.7% carbon, 17% chromium and 1% molybdenum and can be used as kitchen knives and scissors. The microstructure and properties of the tested alloys after quenching at 980 - 1100 °C and low tempering were investigated by means of optical microscope (OM), scanning electron microscope (SEM), Rockwell hardness tester and impact tester. The results show that the microstructure consists of acicular martensite, carbides and a litter retained austenite after quenching and tempering. The carbides are mainly (Fe,Cr)23C6. The content of retained austenite increases with the increase of the quenching temperature. The solubility of carbon in martensite changes similarly. The martensite gets coarser as the quenching temperature increasing. The maximum value of hardness is 59 HRC, when the quenching temperature is 1060 °C. The impact toughness increases when the quenching temperature increases from 980 °C to 1080 °C and then decreases. The suitable heat treatment process for this alloy is quenching at 1060 °C~1080 °C for 30 min and then tempering at 200°C.


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