Zheng Zhang, Yanbao Guo, Wanjun Li, Deguo Wang and Yongjie Zhou
The exploration of the polar regions is of immeasurable potential. It brings great challenges to tribology in the extreme environment. Moreover, the static friction force is an…
Abstract
Purpose
The exploration of the polar regions is of immeasurable potential. It brings great challenges to tribology in the extreme environment. Moreover, the static friction force is an essential index of the braking performance. The purpose of this paper is the static friction force between the rubber of marine pipe tensioner and the ice bead.
Design/methodology/approach
The frictional phenomena were studied for rubber-ice bead at different contact positions (front edge, front part and end part) by means of image processing and measuring. Also, the image sequences of the contact were combined with friction force and displacement data.
Findings
As rubber across the ice bead, the forces of rubber and ice bead at different contact positions determined the order of static friction force (front edge > front part > end part). Meanwhile, there were two different contact states in this process. In addition, under the low tangential load growth rate, the higher temperature can increase the static friction force by increasing the viscoelasticity and contact area of rubber.
Originality/value
The research on the static friction of rubber-ice bead leads to more controlled and higher friction levels during marine pipeline laying.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0526/
Details
Keywords
Yanbao Guo, Zhenyuan Liu, Hui Huang, Deguo Wang and Renyang He
The corrosion of buried steel pipelines is becoming more serious because of stress corrosion, stray current corrosion and other reasons. This paper aims to study the various…
Abstract
Purpose
The corrosion of buried steel pipelines is becoming more serious because of stress corrosion, stray current corrosion and other reasons. This paper aims to study the various alternating current (AC) interference densities on the stress corrosion cracking behaviors of X80 steel samples under cathodic protection (CP) in the simulated soil electrolyte environment by using an electrochemical method.
Design/methodology/approach
The change of corrosion rate and surface morphology of the X80 steel samples at various AC current densities from 0 to 150 A/m2 or CP potential between −750 and −1,200 mV in the soil-simulating environment was revealed by the electrochemical methods and slow strain rate testing methods.
Findings
The results revealed that with the increase of interference density, the corrosion potential of the X80 steel samples shifted to the negative side, and the corrosion pitting was observed on the surface of the sample, this may cause a danger of energy leak. Moreover, the corrosion rate was found to follow a corresponding change with the stress–strain curve. Besides, with the introduction of the CP system, the corrosion rate of the X80 steel working electrode decreased at a low cathodic potential, while showed an opposite behavior at high cathodic potential. In this study, the correlation between AC stray current, cathodic potential and stress was established, which is beneficial to the protection of oil and gas pipeline.
Originality/value
Investigation results are of benefit to provide a new CP strategy under the interference of AC stray current corrosion and stress corrosion to reduce the corrosion rate of buried pipelines and improve the safety of pipeline transportation.
Details
Keywords
Yanbao Guo, Hai Tan, Deguo Wang and Tao Meng
With the rapid development of rail transportation and energy-delivery systems, such as buried oil and gas pipelines and high-voltage transmission lines, the alternating current…
Abstract
Purpose
With the rapid development of rail transportation and energy-delivery systems, such as buried oil and gas pipelines and high-voltage transmission lines, the alternating current (AC) corrosion of buried steel pipelines is becoming more serious. This paper aims to study the corrosion behaviours of Q235 buried steel pipelines induced by the alternating stray current, with a set of indoor simulated experiment apparatuses.
Design/methodology/approach
The corrosion of the coating holidays of the buried steel pipelines at various AC current densities from 0 to 200 A/m2 in the soil-simulating environment was revealed by the electrochemical and weight-loss methods.
Findings
The results showed that the corrosion potential of the steel shifted negatively obviously and the corrosion rate of the steel increased with the increasing of AC current density. At a low AC current density, the negative deviation of the corrosion potential of the steel was small and the increase of corrosion rate was slight. However, the negative deviation of the corrosion potential was remarkable and the corrosion rate was greatly increased at a relative higher AC current density. The geometrical shape of the corrosion images indicated the corrosion forms changed from uniform corrosion to local corrosion due to the increase of AC interference.
Originality/value
Investigation results are of benefit to provide a new strategy to forecast and evaluate the AC-induced corrosion of the buried pipelines which could improve the safety of pipeline transportation.
Details
Keywords
Yanbao Guo, Hai Tan, Deguo Wang and Siwei Zhang
Ocean exploration is of importance and in great demand throughout the world. This results in a huge challenge in tribology in the marine environment. Moreover, polymeric materials…
Abstract
Purpose
Ocean exploration is of importance and in great demand throughout the world. This results in a huge challenge in tribology in the marine environment. Moreover, polymeric materials with large molecules or macromolecules play an important role in marine equipment.
Design/methodology/approach
The tribological performance of sea-water-eroded polyether polyurethane (PU) was systematically studied by using a multi-specimen test machine for different durations from 0 to 60 days. Surface characterization technologies, such as scanning electric microscopy energy dispersive spectroscopy, were used to analyze the PU samples.
Findings
It can be found that the COF measured against 316 steel increases with the testing load because of the change of contact areas for the original PU samples. The effect of hydrodynamic lubrication and heat resulted in the decline of the COF with the increase in testing speed. The COF of PU sample immersed for 20 days was the lowest compared with other samples. With the immersion time increased to 60 days, the COF increased first and then decreased. The reduced COF of PU resulted in improved anti-wear performance of the PU sample.
Originality/value
These results enhanced the comprehension of the tribological performances of PU immersed in sea-water.
Details
Keywords
Hai Tan, Yanbao Guo, Junqiang Wang, Deguo Wang and Yongjie Cui
The purpose of this study is to investigate the influence of additive particle size on the anti-corrosion behaviors of polyurethane (PU) coating.
Abstract
Purpose
The purpose of this study is to investigate the influence of additive particle size on the anti-corrosion behaviors of polyurethane (PU) coating.
Design/methodology/approach
The graphite (Gr) and poly-graphite (PGr) were used as large size additive and small size additive, respectively. The immersion test and electrochemical test were used to study the corrosion behaviors.
Findings
In the immersion test, the surface of the bare steel sample was corroded uniformly. However, for the steel samples with coatings, the surfaces were corroded locally. This phenomenon showed that the coating can isolate artificial sea-water and samples and then decreased the corrosion rate. Furthermore, the most severe corrosion was observed on the sample with the Gr/PU coating compared with other anti-corrosion coatings. The results of the electrochemical measurements indicated that the corrosion rate of the sample with PGr/PU coating was approximately two times lower than that of the sample with the Gr/PU coating and the sample with PGr/PU coating was hardest to be corroded.
Originality/value
To have a more objective and direct recognition of the particle size effect on the coating quality.
Hai Tan, Deguo Wang and Yanbao Guo
Abundant oil and gas reservoirs in the deep-water are the valuable non-renewable energy sources. However, sea-water could enhance the corrosion of marine equipment such as…
Abstract
Purpose
Abundant oil and gas reservoirs in the deep-water are the valuable non-renewable energy sources. However, sea-water could enhance the corrosion of marine equipment such as submarine pipe trees. Various coatings, for example, polyurethane (PU) coatings are sprayed on the steel surfaces to enhance the anti-corrosion performance. Thus, to improve the anti-corrosion behavior of PU coatings in sea-water is imperative.
Design/methodology/approach
In this paper, the corrosion behaviors of 4130 carbon steel with and without PU coatings were discussed by electrochemical mean in sea-water. And the graphene additive in different concentrations (0.1, 0.3, 0.6 and 0.9 per cent) were also studied. A series of characterized methods were introduced to identify the anti-corrosion performances of 4130 carbon steel with and without coatings, respectively.
Findings
The results showed that the anti-corrosion property of 4130 carbon steel can enhance obviously with the PU coatings. The graphene additive can further improve the anti-corrosion behaviour of PU coatings and in the concentration of 0.6 per cent the PU/graphene coatings worked best.
Originality/value
This is beneficial for enhancing the service life of marine equipment in an eco-friendly method.
Details
Keywords
Yanbao Guo, Shuhai Liu, Guibin Tan, Liu Yang and Deguo Wang
The wax deposition in oil wells and pipelines is very viciously negative to the petroleum extraction and crude oil transportation, and it even causes severe blockage accident…
Abstract
Purpose
The wax deposition in oil wells and pipelines is very viciously negative to the petroleum extraction and crude oil transportation, and it even causes severe blockage accident. This study aims to describe cleaning experiments performed on wax deposition of different deposition layer and experimental conditions to investigate the removal and tribological properties and chip formation.
Design/methodology/approach
An optical arrangement was used to visually record the cleaning process, whereas the friction forces were measured by a custom-built tribometer. Various measurements were performed with tool rake angles of 45° and −30° and cleaning depths from 1 to 5 mm.
Findings
Results from experiments and modeling suggest that the transition of chip was dependent on rake angle, wax performance and cleaning depth. While the cleaning depth increased, the friction and cleaning resistant force also increased. With the increase of cleaning depth, the wax layer cleaning quantity increased and the chip strengthened; hence, the curvature radius of chip was enhanced to form platy chip. The chip of wax–oil mixture was discontinuous units, and it was easy to adhere on the rake face with the increasing depth of cut. With an increase in cleaning depth, the friction and cleaning-resistant force also increased.
Originality/value
It is concluded that for effectively cleaning and stabilizing of pipeline cleaning machine, different cleaning parameters should be applied to accommodate wax layer or wax–oil mixture.