Evaluation of boron mobility on the phases FeB, Fe 2 B and diffusion zone in AISI 1045 and M2 steels

2007 ◽  
Vol 253 (7) ◽  
pp. 3469-3475 ◽  
Author(s):  
I. Campos ◽  
G. Ramírez ◽  
U. Figueroa ◽  
J. Martínez ◽  
O. Morales
Keyword(s):  
Diffusion Zone ◽  
Aisi 1045 ◽  
And Diffusion ◽  
Boron Mobility

scholarly journals The influence of laser re-melting on microstructure and hardness of gas-nitrided steel

2016 ◽  
Vol 36 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Dominika Panfil ◽  
Piotr Wach ◽  
Michał Kulka ◽  
Jerzy Michalski
Keyword(s):  
Laser Beam ◽  
Laser Treatment ◽  
Diffusion Zone ◽  
Nitrided Layer ◽  
Nitriding Process ◽  
Beam Power ◽  
Gas Nitriding ◽  
Nitrided Steel ◽  
Laser Beam Power ◽  
And Diffusion

Abstract In this paper, modification of nitrided layer by laser re-melting was presented. The nitriding process has many advantageous properties. Controlled gas nitriding was carried out on 42CrMo4 steel. As a consequence of this process, ε+γ’ compound zone and diffusion zone were produced at the surface. Next, the nitrided layer was laser remelted using TRUMPF TLF 2600 Turbo CO2 laser. Laser tracks were arranged as single tracks with the use of various laser beam powers (P), ranging from 0.39 to 1.04 kW. The effects of laser beam power on the microstructure, dimensions of laser tracks and hardness profiles were analyzed. Laser treatment caused the decomposition of continuous compound zone at the surface and an increase in hardness of previously nitrided layer because of the appearance of martensite in re-melted and heat-affected zones

Corrosion Properties of Welded Ferritic-Martensitic Steels in Liquid Lead-Bismuth at 600C

2010 ◽  
Author(s):  
Asril Pramutadi Andi Mustari ◽  
Minoru Takahashi
Keyword(s):  
Oxide Layer ◽  
Fusion Zone ◽  
Base Metal ◽  
Diffusion Zone ◽  
Corrosion Test ◽  
Electron Beam Welding ◽  
Electrical Conductance ◽  
Grain Structure ◽  
Liquid Lead ◽  
And Diffusion

A static corrosion test for ferritic-martensitic steel HCM12A with three types of welding in lead-bismuth eutectic (LBE) was conducted at 600°C for 500 h. The specifications of TIG welding, YAG laser welding and electron beam welding were 40A/12V of electrical conductance, 278W/14.3J of heat input and 5.0 mA of beam electric current, respectively. Oxygen concentration was controlled to be about 4.7×10−6wt% by injecting Ar-H2-H2O gas mixture into LBE. After corrosion test, cross sections of the specimens were analyzed by using optical microscope and SEM/EDX. Toughness profiles of fusion zone and base metal were determined by using Vickers hardness tool. The results show coarse grain structure in fusion zone (FZ) and typical ferritic-martensitic grain structure in base metal (BM). It was found that those Cr-rich spinel oxide layer and diffusion zone were formed on the surface. The total thickness of oxide layer and diffusion zone on and in the fusion zone was about 18–30μm. It was much thicker than 10–15μm on BM. The hardness was higher in the fusion zone than in the BM.

scholarly journals Fatigue behavior of Ti-6Al-4V alloy modified by plasma immersion ion implantation: temperature effect.

2018 ◽  
Vol 165 ◽  
pp. 14001
Author(s):  
Verônica Velloso ◽  
Leonardo Nozaki ◽  
Diego Tapia ◽  
Maria Odila Cioffi ◽  
Rogério Oliveira ◽  
...  
Keyword(s):  
Diffusion Zone ◽  
Fatigue Behavior ◽  
Nitrogen Addition ◽  
Nitride Layer ◽  
Fatigue Tests ◽  
Implantation Temperature ◽  
Lattice Strains ◽  
Sample Heating ◽  
Plasma Immersion Ion Implantation ◽  
And Diffusion

This research studied Ti-6Al-4V alloy behavior with two (2) different microstructure subjected to nitrogen addition by PIII treatment, with and without sample heating, under cyclic load. PIII conditions, at 390 °C, were DC voltage of 9.5 kV, frequency of 1.5 kHz and pulse of 40 μs. PIII conditions, with sample heating at 800 °C, were 7 kV, 0.4 kHz and 30 μs. Axial fatigue tests were performed on untreated and treated samples for resistance to fatigue comparison. The untreated Ti-6Al-4V had an annealed microstructure, PIII treatment at 390 °C resulted in a microstructure that has no nitride layer or diffusion zone. In the PIII treatment at 800 °C, the microstructure presented nitride layer and diffusion zone. Resistance to fatigue decreased with PIII treatments in both temperatures. At 390 °C, the treatment created deformation regions and cracks on surface due to nitrogen implantation that formed solid solution with titanium and imposed lattice strains on the crystal lattice. At 800 °C, bulk ductility decrease, increasing of αTi proportion in microstructure due to α case formation and the presence of a ceramic layer dropped fatigue resistance of Ti-6A-4V alloy.

Formation and kinetics of FeB/Fe2B layers and diffusion zone at the surface of AISI 316 borided steels

2010 ◽  
Vol 205 (2) ◽  
pp. 403-412 ◽  
Author(s):  
I. Campos-Silva ◽  
M. Ortiz-Domínguez ◽  
O. Bravo-Bárcenas ◽  
M.A. Doñu-Ruiz ◽  
D. Bravo-Bárcenas ◽  
...  
Keyword(s):  
Diffusion Zone ◽  
Aisi 316 ◽  
Kinetics Of ◽  
And Diffusion

Application of integral method for investigating the boriding kinetics of AISI 316 steel

2020 ◽  
Vol 117 (2) ◽  
pp. 202
Author(s):  
Chaima Zouzou ◽  
Mourad Keddam
Keyword(s):  
Diffusion Model ◽  
Diffusion Zone ◽  
Integral Method ◽  
Differential Algebraic System ◽  
Kinetics Of Formation ◽  
Particular Solution ◽  
Aisi 316 ◽  
Good Concordance ◽  
Kinetics Of ◽  
And Diffusion

The present work is dealing with the modelling of boriding kinetics of AISI 316 steel in the temperature range 1123–1273 K. A diffusion model based on the integral method was used in order to investigate the kinetics of formation of FeB and Fe2B layers and that of diffusion zone formed on AISI 316 steel by considering the presence of boride incubation times. By using a particular solution of the resulting differential algebraic system, the diffusion coefficients in FeB, Fe2B and diffusion zone (DZ) were estimated as well as the corresponding values of activation energies. Finally, this present diffusion model has been experimentally validated for two additional boriding conditions (1243 K for 3 and 5 h of treatment). A good concordance was observed between the experimental and the simulated results in terms of layers’ thicknesses.

Effect of Hot-Dip Silicon-Aluminizing on the Anti-Carburization Behavior of High-Temperature-Resistant Steel HK40

2006 ◽  
Vol 118 ◽  
pp. 173-178 ◽  
Author(s):  
Fei Xie ◽  
John Morral
Keyword(s):  
High Temperature ◽  
Diffusion Zone ◽  
Molten Aluminum ◽  
Energy Dispersive Spectrum ◽  
Resistant Steel ◽  
X Ray Diffraction ◽  
Silicon Alloys ◽  
X Ray ◽  
Excellent Property ◽  
And Diffusion

High-temperature-resistant (HTR) austenitic steel HK40 is employed for being silicon-aluminized by being hot-dipped in molten aluminum and silicon alloys and diffused subsequently at 1200°C. The phases, microstructures and concentration for elements of interest in the treated case are investigated by x-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrum of x-ray (EDS). The case composes of three main zones: the former hot-dipped coating zone, inter-diffusion zone, and diffusion zone of Al and Si, all of which contain quite higher contents of aluminum and silicon than substrate. Pack-carburization is used for assessing the anti-carburization behavior of the treated case. The treated case shows excellent property in hindering the inward-diffusion of carbon, even if the former hot-dipped coating zone spalls off with only diffusion zone left. High contents of aluminum, silicon and oxygen are still detected on surface of the silicon-aluminized specimen after carburization. Good anti-carburization ability of the silicon-aluminized specimen is believed mainly to be the result of the dense and stable Al2O3 and SiO2 films formed on the surface.

scholarly journals The Effect of Temperature Distribution during Laser Heat Treatment of Gas-Nitrided 42CrMo4 Steel on the Microstructure and Mechanical Properties

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 824
Author(s):  
Dominika Panfil-Pryka ◽  
Michal Kulka ◽  
Natalia Makuch ◽  
Jerzy Michalski ◽  
Piotr Dziarski
Keyword(s):  
Heat Treatment ◽  
Young’S Modulus ◽  
Diffusion Zone ◽  
Young's Modulus ◽  
Nitrided Layer ◽  
Laser Heat Treatment ◽  
Laser Track ◽  
Fine Grained ◽  
Laser Heat ◽  
And Diffusion

A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable nitriding potential in order to limit the thickness of a brittle ε zone. The microstructure consisted of the compound ε + (ε + γ’) zone and diffusion zone (nitric sorbite with γ’ precipitates). Such a layer was subjected to laser heat treatment with or without remelting. The single laser tracks were formed using various laser beam powers (in the range of 0.234–0.624 kW) and scanning rates (in the range of 2.24–3.84 m·min−1) and the same laser beam diameter (2 mm). The microstructure of laser-modified nitrided layer usually consisted of re-melted zone (MZ) with coarse-grained nitric martensite Feα’ and possible ε precipitates, heat-affected zone (HAZ) with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. Sometimes, the compound zone was partially re-melted and an amount of iron nitrides remained in the MZ. Only one laser track was characterized by the different microstructure, consisting of the compound ε + (ε + γ’) zone, HAZ with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. This laser track was formed without visible effects of remelting. The effect of temperature distribution during laser heat treatment of gas-nitrided 42CrMo4 steel on the microstructure and mechanical properties was studied. The equations developed by Ashby and Esterling were used in order to determine the temperature distribution along the axis of each laser track. Taking into account the temperature profiles, it was possible to calculate the depths of MZ and HAZ. These predicted values were compared to those-measured based on the microstructure observations, obtaining good compatibility. The microstructure of the produced surface layers influenced the mechanical properties such as hardness and Young’s modulus. The hardness of MZ was higher than that of ε zone and lower than that of ε + γ’ zone when compared to nitrided layer. Whereas Young’s modulus of MZ was significantly higher than those characteristic of the compound zone in gas-nitrided layer (both ε and ε + γ’ zone) and similar to that of HAZ. The laser heat treatment (LHT) without remelting resulted in the similar hardness and slightly higher Young’s modulus of ε zone in comparison with the nitrided layer. Simultaneously, such a treatment of the nitrided layer did not influence the hardness and the Young’s modulus of ε + γ’ zone considerably. The hardness of HAZ was higher than that of MZ and that of the same area of diffusion zone in the nitrided layer because of the presence of fine-grained nitric martensite with γ’ precipitates after laser quenching.

Optimum Bifurcating-Tube Tree for Gas Transport

2005 ◽  
Vol 127 (3) ◽  
pp. 550-553 ◽  
Author(s):  
Tianshu Liu
Keyword(s):  
Diffusion Zone ◽  
Convection Zone ◽  
Gas Transport ◽  
Mass Transfer Rate ◽  
Length Distribution ◽  
Diameter Distribution ◽  
Optimality Principle ◽  
Optimality Principles ◽  
Diffusion Mass ◽  
And Diffusion

This paper describes optimality principles for the design of an engineering bifurcating-tube tree consisting of the convection and diffusion zones to attain the most effective gas transport. An optimality principle is formulated for the diffusion zone to maximize the total diffusion mass-transfer rate of gas across tube walls under a constant total-volume constraint. This optimality principle produces a new diameter distribution for the diffusion zone in contrast to the classical distribution for the convection zone. In addition. this paper gives a length distribution for an engineering tree based on an optimality principle for minimizing the total weight of the tree under constraints of a finite surface and elastic criteria for structural stability. Furthermore, the optimum branching angles are evaluated based on local optimality principles for a single bifurcating-tube branch.

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