scholarly journals Hardness Profile Prediction for a 4340 Steel Spline Shaft Heat Treated by Laser Using a 3D Modeling and Experimental Validation

2016 ◽  
Vol 04 (04) ◽  
pp. 9-19
Author(s):  
Mahdi Hadhri ◽  
Abderazzak El Ouafi ◽  
Noureddine Barka
Keyword(s):  
3D Modeling ◽  
Experimental Validation ◽  
Hardness Profile ◽  
4340 Steel ◽  
Heat Treated ◽  
Spline Shaft

Prediction of Hardness Profile of 4340 Steel Plate Heat Treated by Laser Using 3D Model and Experimental Validation

2014 ◽  
Author(s):  
G. Billaud ◽  
N. Barka ◽  
A. El Ouafi ◽  
A. Chebak ◽  
J. Brousseau
Keyword(s):  
3D Model ◽  
Steel Plate ◽  
Beam Power ◽  
Hardness Profile ◽  
Nonlinear Behaviour ◽  
Good Precision ◽  
Laser Technique ◽  
Plate Heat ◽  
4340 Steel ◽  
Heat Treated

The paper presents a study of hardness profile of 4340 steel plate heat treated by scanning laser technique using 3D model. The proposed approach is carried out in three distinguished steps. First, a commercial software 3D model was developed using an adequate formulation and taking into account the nonlinear behaviour of the material. Second, the hardness curve is approximated from the temperature distribution using metallurgical assumptions related to the kinetic transformation and the temperature-time transformation diagram. Then, the case depth is analyzed quantitatively versus the beam power density and scanning speed. Finally, the developed approach is validated using experimental tests. The gap between simulation and experience results is determined. The obtained results allow predicting of the hardness profile with a fairly good precision.

scholarly journals Experimental Investigation of Laser Surface Transformation Hardening of 4340 Steel Spur Gears

2019 ◽  
Vol 3 (3) ◽  
pp. 72 ◽  
Author(s):  
Borki ◽  
El Ouafi ◽  
Chebak
Keyword(s):  
Experimental Investigation ◽  
Process Parameters ◽  
Laser Power ◽  
Laser Surface ◽  
Hardness Profile ◽  
Spur Gears ◽  
Depth Variation ◽  
Profile Shape ◽  
4340 Steel ◽  
Surface Transformation

This paper presents an experimental investigation of laser surface transformation hardening (LSTH) of 4340 steel spur gears using regression analysis. The experimental work is focused on the effects of various LSTH parameters on the hardness profile shape and the hardened depth variation. The investigations are based on a structured design of experiments and improved statistical analysis tools. The experimentations are carried out on AISI 4340 steel spur gears using a commercial 3 kW Nd:YAG laser system. Laser power, scanning speed, and rotation speed are used as process parameters to evaluate the variation of the hardened depth and to identify the possible relationship between the process parameters and the hardened zone physical and geometrical characteristics. Based on the experimental data and analysis of variance, the direct and interactive contributions of the process parameters on the variation of the hardness profile shape and the hardened depth are analyzed. The main effects and the interaction effects are also evaluated. The results reveal that all the process parameters are relevant. The cumulative contribution of the three parameters in the hardened depth variation represents more than 80% with a clear predominance of laser power. The contribution of the interactions between the parameters represents 12% to 16%. The resulting hardness values are relatively similar for all the experimental tests with about 60 HRC. The evaluation of the produced regression models for hardened depth prediction shows limited performance suggesting that the predictive modeling process can be improved.

Polarization of Strained AISI 4340 Steel in Oxygenated NaCl Solutions

CORROSION ◽  
1966 ◽  
Vol 22 (8) ◽  
pp. 229-237 ◽  
Author(s):  
S. M. TOY
Keyword(s):  
Tensile Load ◽  
Corrosion Current ◽  
Cell System ◽  
Cathodic Polarization Curve ◽  
Aisi 4340 Steel ◽  
Sodium Chloride Solutions ◽  
4340 Steel ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
Aisi 4340

Abstract Electrode reactions involved in the stress corrosion of AISI 4340 steel in sodium chloride solutions were studied by pulse galvanostatic and potentiostatic experiments. The redox cell system involves two principal cathodic reactions and one anodic reaction. These electrochemical reactions are affected by the application of stress, by change in pH, by oxygen content and the heat-treated condition of the materials. The effect of stress is to shift the cathodic polarization curve in an electropositive direction with increasing tensile load. It is equivalent to cathodic control for the conditions investigated and is described by the electrochemical interpretation, based on the coupling of the redox branches which produce the largest corrosion current.

Microstructural Changes of FSX-414 Superalloy during TLP Bonding

2011 ◽  
Vol 312-315 ◽  
pp. 399-404 ◽  
Author(s):  
R. Bakhtiari ◽  
A. Ekrami
Keyword(s):  
Aging Treatment ◽  
Eutectic Structure ◽  
Isothermal Solidification ◽  
Heat Treatment Condition ◽  
Hardness Profile ◽  
Solution Treated ◽  
Tlp Bonding ◽  
Heat Treated ◽  
M23c6 Type ◽  
Bond Region

The as-cast FSX-414 Co-based superalloy samples were solution treated at 1150oC for 4h and then aged at 980oC for 4h. Specimens for joining were cut from the as-cast ingot and TLP bonding carried out at the same conditions as for the solution and solution+aging treatment, using MBF-30 interlayer. Microstructures were studied for as-cast, heat treated and TLP bonded specimens. These studies showed that the ununiform distributed carbides of MC type in the as-cast specimens replaced by M23C6 type carbides with uniform distribution in the heat treated microstructure. Due to complete isothermal solidification, no eutectic structure in the bond region were wasobserved, but some intermetallics in the diffusion affected zone (DAZ) were observed. Microhardness tests were used to compare the hardness of age hardened specimens with bonded specimens at the same heat treatment condition. Hardness profile also showed a peak in DAZ region in spite of complete isothermal solidification.

scholarly journals The effect of protective atmosphere on decarburisation of the heat-treated surface of steel

2017 ◽  
Vol 64 (4) ◽  
pp. 199-204
Author(s):  
Marica Prijanovič Tonkovič ◽  
Miha Knez
Keyword(s):  
Surface Layer ◽  
Heat Treating ◽  
Protective Atmosphere ◽  
Hardness Profile ◽  
Heat Treated ◽  
Protective Atmospheres ◽  
Different Types ◽  
Mixed Microstructure

AbstractIn heat-treating furnaces, many different types of protective atmospheres are used. This article researches the effect of protective atmospheres on the quality of the surface layer of bolts during the process of heating to reach the temperature of hardening. For this research, we produced specimens that were annealed in the furnace with two different types of protective atmosphere, i.e. in atmospheres of endothermic gas and nitrogen. After hardening and tempering, we measured the hardness of the specimens and investigated the microstructure. We measured the hardness profile from the surface to the inside of the product. We found that the hardness of the surface of the tested product was lower while using protective atmosphere of nitrogen due to the occurrence of ferrite. The depth of the decarburised layer in this atmosphere reached up to 70 mm, where predominantly there was a microstructure of ferrite on the surface, and then, with depth, an increasingly mixed microstructure of ferrite and martensite was found. The depth of the decarburised layer for sample treated in endothermic gas was minimal (i.e. 10 mm) on the surface.

Plasma Nitriding of Hard Chromium Electroplated Low Alloy AISI 4340 Steel in Pure Nitrogen Gas Atmosphere

2020 ◽  
Vol 65 ◽  
pp. 135-144
Author(s):  
Soheib Mokhtara ◽  
Mosbah Zidani ◽  
Mohamed Mounis Alim ◽  
Said Mechachti
Keyword(s):  
Plasma Nitriding ◽  
Morphological Properties ◽  
Nanoindentation Test ◽  
Hardness Profile ◽  
Nitrogen Gas ◽  
Pure Nitrogen ◽  
Aisi 4340 Steel ◽  
Hard Chromium ◽  
4340 Steel ◽  
Aisi 4340

Duplex treatments are surface modification techniques used to enhance the surface properties of steels. In this study, hard chromium electroplated AISI 4340 steel was plasma nitrided in pure nitrogen gas at 600°C for 90 min. The structural and morphological properties were analysed by an X-ray diffractometer and a scanning electron microscope (SEM), respectively. The hardness profile was obtained by a multicycle nanoindentation test and the tribological properties by a ball-on-disk test at room temperature. The results showed that the duplex layer was composed mainly of Cr2N and it had a rough surface morphology with a network of micro-cracks. The highest values of hardness were registered in the nitrogen diffusion layer beneath the outer porous thin layer. The friction coefficient and the specific wear rate after plasma nitriding were reduced by 3 and 5 factors, respectively.

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