Diffusion of Hard Coatings on Ductile Cast Iron

2012 ◽  
Vol 1481 ◽  
pp. 105-112 ◽  
Author(s):  
N. López Perrusquia ◽  
M. Antonio Doñu Ruiz ◽  
E. Y. Vargas Oliva ◽  
V. Cortez Suarez

ABSTRACTThis work estimate the growth kinetics of Fe2B coatings created on surface nodular cast iron ASTM A-536 class 80-56-06. The Fe2B coatings were formed by power packaging boriding process, considering three temperatures and exposure times different treatment. The hard coatings were evaluated through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The model of diffusion employs the mass balance equation at the (Fe2B/substrate) interface to evaluate the boron diffusion coefficient in the Fe2B coating DFe2B, an expression of the parabolic growth constant, the instantaneous velocity of the Fe2B/substrate interface, and the weight gain in the boriding sample were establish as a function of the parameter ε(T) and η(T), dependents of boriding process in function of the temperature related and the time of boriding t0 (T), respectively in the Fe2B coating. Model validation was extended considering the treatment of 1273 and 1123 K for 10 h respectively, obtaining a good correlation with experimental data.

1977 ◽  
Vol 9 (12) ◽  
pp. 1462-1467
Author(s):  
I. S. Guz' ◽  
A. P. Lyubchenko ◽  
V. M. Matsevityi ◽  
S. L. Molodtsov ◽  
L. A. Smirnova

2017 ◽  
Vol 17 (4) ◽  
pp. 109-114 ◽  
Author(s):  
J. Meško ◽  
R. Nigrovič ◽  
A. Zrak

Abstract This article deals with the technology and principles of the laser cutting of ductile cast iron. The properties of the CO2 laser beam, input parameters of the laser cutting, assist gases, the interaction of cut material and the stability of cutting process are described. The commonly used material (nodular cast iron - share of about 25% of all castings on the market) and the method of the laser cutting of that material, including the technological parameters that influence the cutting edge, are characterized. Next, the application and use of this method in mechanical engineering practice is described, focusing on fixing and renovation of mechanical components such as removing the inflow gate from castings with the desired quality of the cut, without the further using of the chip machining technology. Experimental samples from the nodular cast iron were created by using different technological parameters of laser cutting. The heat affected zone (HAZ), its width, microstructure and roughness parameter Pt was monitored on the experimental samples (of thickness t = 13 mm). The technological parameters that were varied during the experiments included the type of assist gases (N2 and O2), to be more specific the ratio of gases, and the cutting speed, which ranged from 1.6 m/min to 0.32 m/min. Both parameters were changed until the desired properties were achieved.


2011 ◽  
Vol 328-330 ◽  
pp. 1297-1300
Author(s):  
Guang Si Luo

Austempered ductile cast iron is newly developed engineering material with a favorable combination of comprehensive mechanical properties. Its properties, such as good comprehensive mechanical properties, high fatigue strength, and good fiction and wear characteristics are included. The application of ADI at home and abroad was presented as well. In order to ensure and improve mechanical properties of ADI, it should ensure high rank nodularity in terms of nodular cast iron, improve graphite nodules, reduce segregation and properly cut down the content of silicon and manganese. While in terms of heat treatment, in order to achieve ideal austenite ferrites, stable and reliable heat treatment process as well as relevant equipment is required.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Marco Antonio Doñu Ruiz ◽  
David Sánchez Huitron ◽  
Ernesto David Garcia Bustos ◽  
Víctor Jorge Cortés Suárez ◽  
Noé López Perrusquia

The effect of boron powder on surface AISI W2 steel and growth kinetic of the boride layer is studied. Boron powder mixture was used in the powder pack boriding; this process was carried out in the temperature range from 1173 to 1273 K with exposure times ranging from 2 to 8 h. The presence of boride was confirmed by optical microscopy, X-ray diffraction, and the distribution of alloy elements in boride layers with energy-dispersive spectrometry using scanning electron microscopy. A mathematical model of the growth kinetics of the single layer was proposed and boron diffusion coefficient was determined by mass balance equation. The morphology of Fe2B layer was smooth and boron activation energy in W2 steel was estimated as 187.696 kJ·mol−1. The kinetic model was validated with two experimental conditions, a contour diagram describing the evolution of Fe2B layer as a function of time and temperature parameters for industrial application.


2020 ◽  
Vol 20 (4) ◽  
pp. 38-48
Author(s):  
N. Ucar ◽  
M. Yigit ◽  
A. Calik

AbstractBoriding of 34CrNiMo6 steel was performed in a solid medium consisting of Ekabor-II powders at 1123, 1173 and 1223 K for 2, 4 and 6 h. Morphological and kinetic examinations of the boride layers were carried out by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The thicknesses of the boride layers ranged from 22±2.3 to 145±4.1 depending on boriding temperature and time. The hardness of boride layer was about 1857 HV0.1 after boriding for 6 h at 1223 K, while the hardness of the substrate was only around 238 HV0.1. Growth rate constants were found to be between 1.2×10−13 – 9.8×10−13 m2/s depending on temperature. The activation energy for boron diffusion was estimated as 239.4±8.6 kJ mol−1. This value was comparable to the activation energies reported for medium carbon steels in the literature.


2020 ◽  
Vol 856 ◽  
pp. 92-98
Author(s):  
Janthira Chantarach ◽  
Rungsinee Canyook

The purpose of the study was to inspect microstructure, mechanical properties and impact toughness of ductile cast iron grade FCD450 produced by austempering process. The study focused on austempering parameter, which effected impact toughness of material at low temperature. The FCD450 was initially temperature austenized at 885°C (1625˚F) for 2 hours. Austempering was carried out at three different temperatures of 271°C (520˚F), 313°C (560˚F) and 357°C (675˚F). The austempering temperature were varied at 1.5, 2.5 and 3.5 hours. X-ray diffraction was showed that the austempered ductile cast iron (ADI) microstructure consists of austenite and ferrite. The results showed that when austempered at 357°C (675˚F) for 2.5 hours has highest hardness and impact energy at low temperature. The dimple ductile fracture of ADI fracture surfaces was revealed by scanning electron microscope (SEM).


2019 ◽  
Vol 70 (2) ◽  
pp. 506-511 ◽  
Author(s):  
Cristian Savin ◽  
Carmen Nejneru ◽  
Manuela Cristina Perju ◽  
Costica Bejinariu ◽  
Diana Burduhos-Nergis ◽  
...  

Waste water is an aggressive environment for transport pumps to treatment plants. The pumps used are generally, immersion pumps and are made of various elements like, rotor, stator, housing, screws, flanges, springs, seals, etc. The construction elements of the pumps are made of various metallic materials, such as nodular cast iron, gray cast iron, low alloy steel, stainless steel, aluminum, bronze, brass, copper, etc. When immersed in waste water, the metals form galvanic series. The paper presents the galvanic corrosion analysis of the above-mentioned metals in case the corrosive environment is waste water with various compositions.


Sign in / Sign up

Export Citation Format

Share Document