Influence of plasma nitriding pre‐treatment on the corrosion and tribocorrosion behaviours of PVD CrN , TiN and AlTiN coated AISI 4140 steel in seawater

In the present article, samples made of AISI 4140 steel, pre-treated with plasma nitriding (PN), and coated with different coatings like Titanium Carbonitride (TiCN), Aluminium Chromium Nitride (AlCrN), using Physical Vapor Deposition (PVD) technique, were investigated in terms of their microhardness, surface roughness, and dry sliding wear behaviour. Wear tests were performed with a pin-on-disc machine. Coatings were deposited on plasma nitrided samples. The wear behaviour, and wear mechanisms of TiCN- and AlCrN-coated, PN treated AISI 4140 specimens were investigated using a field emission Scanning Electron Microscope (SEM), equipped with an Energy Dispersive X-ray (EDX) analyzer. An SEM was used to study the surface morphology of the worn surfaces. Also, adhesion tests were conducted to investigate the adhesion quality of the coated specimens. The results of the investigation showed improved wear properties. Furthermore, the compound layer formed during nitriding was found to act as an intermediate hard layer, leading to superior sliding wear properties.

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Experimental Investigation and Statistical Approach to Wear Characterization of Plasma Nitrided AISI 4140 Steel-A Case Study

Manufacturing and Industrial Engineering ◽

10.12776/mie.v15i1-2.804 ◽

2017 ◽

Vol 15 (1-2) ◽

Author(s):

Santosh V. Bhaskar ◽

Hari N. Kudal

Keyword(s):

Plasma Nitriding ◽

Interaction Effects ◽

Wear Volume ◽

Effective Parameters ◽

Operational Parameters ◽

Sliding Speed ◽

Aisi 4140 Steel ◽

Study Results ◽

Aisi 4140 ◽

The Impact

<p>Components of forming tool dies such as draw ring, ejector pin use AISI 4140 as material for their manufacturing. The integrity of the die cutting tools is essential to achieve adequate product quality. In present study, the influence of plasma nitriding (PN) on the wear behav-iour of AISI 4140 steel was investigated. Full factorial experimental design technique was used to study the main effects and the interaction effects between operational parameters and the response variable. The control factors at their two levels (-1 and +1) were: applied load (4.905N and 14.715N), sliding speed (3.14 m/s and 5.23 m/s), and sliding distance (500m and 1000m).The parameters were coded as A, B, and C, consecutively, and were investigated at two levels (-1 and +1). Response selected was Wear Volume Loss (WVL). The effects of in-dividual variables and their interaction effects for dependent variables, namely, WVL were determined. The process of selecting significant factors, based on statistical tools, is illustrat-ed. Analysis of Variance (ANOVA) was performed to know the impact of individual factors on the WVL. Untreated and PN treated AISI 4140 specimens were investigated using field emission Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX) analyzer. Finally diagnostics tools were used to check adequacy of the model in terms of assumptions of ANOVA. ‘Design Expert-7’ and ‘Minitab 17’ softwares were used in the study. Results of statistical analysis indicate that the most effective parameters in the WVL were load and sliding speed. The interaction between load and sliding speed was the most influencing interaction. Results of regression analysis indicate regression coefficient (R2) to be above 90% which suggests good predictability of the model. ‘Predicted-R2’ and ‘Adjusted-R2’, found to be in good agreement with R2, for both the materials under investigation. More-over, results of SEM microscopy suggest PN to be an effective technique to reduce wear.</p>

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