Tribological Properties of Connecting Rod High Strength Screws Improved by Surface Peening Treatments

Bolted joints are highly loaded components and serious issues may arise from improper fastening and in particular from too high or too low preload. Friction at the underhead plays an important role, as it significantly affects the achievable preload for fixed and controlled tightening torque. In addition, multiple tightening is usually performed on connecting rod screws, which may be a further source of friction increment. This study investigates the effect of two surface treatments, shot-peening and deep-rolling, on the tribological properties upon bolt fastening. This topic was tackled experimentally and the campaign involved MJ9 X 1 4 g grade 13.9 36 NiCrMo connecting rod screws, in both lubricated and dry conditions. The results, processed by statistical tools, indicate that deep-rolling does not affect friction, whereas shot-peening yields significant benefits. As an effect of the generation of dimples and multiple contacts, it is able to lower (up to 25%) the bearing frictional coefficient in lubricated conditions, also making the friction level independent of the number of re-tightenings. For a dry surface, an even higher friction decrease (up to 30%) is achieved. Without lubrication, the friction coefficient keeps increasing for the incremented number of tightenings, but the increase rate is lowered with respect to the untreated surface.

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Experimental Investigation on the Effect of Shot Peening and Deep Rolling on the Fatigue Response of High Strength Fasteners

Metals ◽

10.3390/met9101093 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1093 ◽

Cited By ~ 3

Author(s):

Reggiani

Keyword(s):

Fatigue Life ◽

Shot Peening ◽

High Strength Steels ◽

High Strength ◽

Experimental Tests ◽

Published Data ◽

Deep Rolling ◽

Beneficial Impact ◽

The Impact ◽

Fatigue Life Enhancement

Shot-peening and deep rolling are mechanical surface treatments that are commonly applied to enhance the fatigue performances of components, owing to their capacity to generate compressive residual stresses and induce work hardening. However, literature is still poor of published data concerning the application of these treatments to high strength steels fasteners, although these represent a class of components among the most widespread. In the present work, the impact of deep rolling and shot-peening performed in the underhead radius of two set of fasteners made of 36NiCrMo and 42CrMoV for fatigue life enhancement has been investigated. The experimental tests consisted of six combinations of shot-peening and deep rolling, including the non-treated state. Two test campaigns have been sequentially carried out with different process parameters and treatment sequences. The results always showed a beneficial impact of the deep rolling on fatigue, especially for the 42CrMoV steel. Conversely, the effect of the shot-peening strongly depended on the selected set of parameters, alternatively leading to an improvement or a worsening of the fatigue life in relation to the level of induced surface roughness.

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Preparation of PEEK/MWCNTs composites with excellent mechanical and tribological properties

High Performance Polymers ◽

10.1177/0954008317750726 ◽

2018 ◽

Vol 31 (1) ◽

pp. 43-50 ◽

Cited By ~ 10

Author(s):

Yingshuang Shang ◽

Xian Wu ◽

Yifan Liu ◽

Zilong Jiang ◽

Zhaoyang Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Tribological Properties ◽

Frictional Coefficient ◽

Crystallization Rate ◽

High Strength ◽

Multiwalled Carbon ◽

Structural Morphology ◽

Mechanical And Tribological Properties ◽

The Coefficient Of Friction ◽

Properties Of Composites

The high strength of multiwalled carbon nanotubes (MWCNTs) indicates promising properties for industry applications to reduce frictional coefficient and improve mechanical properties, yet few researches have referred to its structural morphology on the thermal, mechanical, and tribological properties of composites. In this work, three different lengths of MWCNTs were used to prepare polyether ether ketone (PEEK) composites and investigate the effect of structural morphology of MWCNTs on the thermal, mechanical, and tribological properties of composites. Different lengths of MWCNTs endowed PEEK composites with different thermal, mechanical, and tribological properties. On thermal and mechanical properties, the incorporation of 10–30 μm length of MWCNTs increased more the effectiveness on the crystallization rate, showing a higher crystallization temperature and the best mechanical properties of the PEEK composites. On tribological properties, approximately 50 μm MWCNTs can effectively decrease adhesive wear, which is a benefit of forming a thin transfer film, thereby effectively decreasing the coefficient of friction and improving the wear resistance.

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Effects of Surface Treatments on the Fatigue Response of High Strength Fasteners

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.813.352 ◽

2019 ◽

Vol 813 ◽

pp. 352-357 ◽

Cited By ~ 1

Author(s):

Barbara Reggiani ◽

Giorgio Olmi ◽

Leonardo Orazi ◽

Luca Tomesani ◽

Stefano Fini ◽

...

Keyword(s):

Fatigue Life ◽

Shot Peening ◽

Rolling Force ◽

High Strength ◽

Deep Rolling ◽

Experimental Campaign ◽

Life Enhancement ◽

The Impact ◽

Fatigue Life Enhancement ◽

Treated State

The aim of the present work was the assessment of the impact of deep-rolling and shot-peening performed in the underhead and in the unthreaded shank of two high strength screws (36 NiCrMo and 42 CrMoV) for fatigue life enhancement. The experimental campaign consisted of six combinations, including the non-treated state. The aforementioned treatments were evaluated alone or with shot-peening performed after deep-rolling in the underhead fillet of the screws. Deep rolling was carried out at the optimal rolling force, whereas two shot diameters were considered for shot-peening (Z100 and UFS70). The results have been evaluated in terms of fatigue limits and factor effects have been assessed by marginal mean plots.

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Increasing the fatigue strength of high-strength steel parts by repeated treatment with shot peening

10.36652/0042-4633-2020-8-79-82 ◽

2020 ◽

pp. 79-82

Author(s):

G.N. Kravchenko ◽

K.G. Kravchenko

Keyword(s):

Fatigue Strength ◽

Shot Peening ◽

High Strength Steel ◽

High Strength ◽

Resource Recovery ◽

Repeated Treatment ◽

Multiple Processing

The effectiveness of multiple hardening by shot peening of samples made of «30ХГСН2А» high-strength steel to increase their fatigue strength is experimentally established. Repeated hardenings allow not only to restore the original durability and even significantly increase it. Keywords fatigue strength, durability, resource recovery, multiple processing by shot peening, repeated hardening, high-strength steel. [email protected]

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Improving reliability of high‐strength steel designed against fatigue limit using surface crack nondamaging technology by shot peening

Fatigue & Fracture of Engineering Materials & Structures ◽

10.1111/ffe.13460 ◽

2021 ◽

Vol 44 (6) ◽

pp. 1602-1610

Author(s):

Ki‐Woo Nam ◽

Kotoji Ando ◽

Min‐Heon Kim ◽

Koji Takahashi

Keyword(s):

Fatigue Limit ◽

Surface Crack ◽

Shot Peening ◽

High Strength Steel ◽

High Strength

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Closure to “Surface Treatment of High-Strength Bolted Joints”

Journal of the Structural Division ◽

10.1061/jsdeag.0002340 ◽

1969 ◽

Vol 95 (8) ◽

pp. 1768-1769

Author(s):

Conrad P. Heins ◽

Charles T. G. Looney

Keyword(s):

Surface Treatment ◽

High Strength ◽

Bolted Joints

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Exploration of novel faying surface treatment for high-strength frictional bolted joints to enhance its after-slip performance

10.2749/ghent.2021.1684 ◽

2021 ◽

Author(s):

Hitoshi Moriyama ◽

Ryo Sakura ◽

Takashi Yamaguchi ◽

Takai Toshikazu ◽

Yuta Yamamoto

Keyword(s):

Surface Treatment ◽

Load Transfer ◽

High Strength ◽

Bolted Joints ◽

Deformation Capacity ◽

Slip Coefficient ◽

Faying Surface ◽

Treatment Concepts ◽

Local Slip

<p>Welded joints is adopted rather than bolted joints for megastructure’s connections because the former can carry large force. However, the former has several problems, such as quality control of welding in situ, which the latter can solve. By contrast, as the load transfer ratio of each bolt becomes uneven proportionally to the number of bolts, local slip around extreme bolts occurs before the whole slip. Extreme bolts to which a large shear force is applied will break before other bolts. For utilizing the strength of all bolts, the problem is solved by improving shear deformation capacity in faying surface with novel surface treatment. Here, the treatment concepts were explored, and the coating’s effectiveness was evaluated through friction tests. The deformation capacity can be twice or more than that of conventional treatment, and the slip coefficient doesn’t depend on contact pressure. These features have the advantage to give stable slip behaviour.</p>

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Tribological property of the cobalt—chromium femoral head with different regions of wear in total hip arthroplasty

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/09544119jeim709 ◽

2009 ◽

Vol 224 (4) ◽

pp. 541-549 ◽

Cited By ~ 9

Author(s):

C-T Duong ◽

J-S Nam ◽

E-M Seo ◽

B P Patro ◽

J-D Chang ◽

...

Keyword(s):

Surface Roughness ◽

Femoral Head ◽

Total Hip Arthroplasty ◽

Tribological Properties ◽

Hip Arthroplasty ◽

Frictional Coefficient ◽

Cobalt Chromium ◽

Bearing Materials ◽

Frictional Coefficients ◽

Wear Region

The tribological properties of engineering and biological materials have been investigated at microscale levels through the calculation of the surface roughness and frictional coefficient using atomic force microscopy (AFM). Although a number of previous studies have reported the frictional coefficients of diverse bearing materials in total hip arthroplasty (THA), the relationship between the surface roughness and frictional coefficient of bearing materials of THA have not been reported, and furthermore, the tribological properties for different wear regions of a cobalt-chromium (Co—Cr) femoral head have not been well identified. Therefore, the objective of this study is to investigate the relationships between the surface roughness, frictional coefficient, and hardness for both the main-wear and the least-wear regions of a Co—Cr femoral head 10 years after THA. The average Vickers hardness of the Co—Cr femoral head was 380.7 ± 11.3 HV. With the scanned area of 25 μm×25 μm through AFM, the frictional coefficients of the main-wear and the least-wear regions were 0.229 ± 0.054 and 0.243 ± 0.059, respectively, and showed no statistical differences between these two regions ( p = 0.449). However, differences in the surface roughness ( Rq) between the main-wear region ( Rq = 96.5 ± 26.2 nm) and the least-wear region ( Rq = 17.7 ± 4.2 nm) were statistically significant ( p<0.0001). The results of the current study suggest that the frictional property of the Co—Cr femoral head is not significantly correlated with its surface roughness, and also provide guidelines for improving the surface characteristics of metallic implant materials.

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