Two-body abrasion and synergy in abrasion-corrosion of martensitic and complex phase steel

Offshore applications in general and suction pipes of dredgers, in particular, suffer perpetually in severe abrasive action of sand and corroding action of seawater. Therefore, the coupled damage tribocorrosion becomes of the essence which is the main focus of the current work. A customized two-body abrasion–corrosion test rig was designed and constructed in-house by coupling the pin abrasion tester (ASTM-G132) and a three-electrode electrochemical system. The synergy of the abrasion–corrosion system was successfully quantified for martensitic and complex phase steel in three different electrolytes: distilled water, 3.5 wt% NaCl and seawater from North sea. A significant influence of wear over corrosion was observed however, the influence of corrosion over wear was very negligible. In general, martensitic steel performed slightly better than dual phase steel in all the media except seawater. Additionally, abrasion was studied in terms of single asperity contact as well as multiple asperity contact. Within the tested load range, similar specific wear rate was observed in both the materials. Lastly, single asperity scratch was also modelled using finite-element method (ABAQUS 6.14). A stress-controlled parametric model was developed to study the influence of indenter geometry and scratch load on scratch geometry

Synergism in multi-asperity abrasion-corrosion of martensitic and dual phase steels in three aqueous electrolytes

Synergism is noted to expedite the material degradation kinetics in wear-corrosion systems. Over the years, many wear-corrosion contact configurations have been explored to grade materials in application oriented environments. Current investigation focuses on quantifying the synergy of abrasion-corrosion in a two-body abrasive wear configuration where abrasive particles interact with metal counter surface, conforming to ASTM G132. Two abrasion resistant steels, i.e., martensitic and dual phase steels, are exposed to tribo-electrochemical conditions in three different aqueous electrolytes, namely distilled water, aqueous salt solution (3.5 wt% NaCl) and seawater from the North Sea. The submerged metal pins are engaged with 1 N normal load and slid against a P180 SiC abrasive paper. In distilled water, both the materials exhibited slowest corrosion kinetics attributed to the absence of ions thus leading to lowest corrosion currents. Overall, martensitic steel displays a better global wear performance than dual phase steel in all media except seawater. Cathodic protection generates lowest specific wear rates in all the experiments except for martensitic steel in distilled water where the observed higher wear rates are suspected to occur due to hydrogen embrittlement. Generally, the influence of abrasive wear on corrosion was much higher than the effect of corrosion on abrasive wear

A multiscale experimental abrasion characteristics of cutting tool materials

Surface interaction in abrasion of multiphase materials such as cermets by hard abrasive particles is a complex phenomenon that requires in-depth understanding at a micro scale. The different characteristics of abrasive particles such as size, hardness and shape creates asymmetric surface topographies on the worn surface. The resultant wear mechanism from abrasive particle is a combination of brittle and ductile failure mode which is associated with different phases of the material. It is essential to understand the fundamental insight and the damage process that causes inconsistence in the scratch patterns in multi-asperity contact. Such interaction is easily mapped using a scale down laboratory studies for understanding the dominating variable (operational and material) and their associated damage mechanisms. In this background, the current investigation evaluates the response of two similarly hard WC-15.6Co (WC-Co) and NbC-12Ni-10Mo2C (NbC-Ni) multiphase cermets during three-body abrasive wear, which was experimentally simulated by a dry sand/rubber wheel test. The study has been performed according to ASTM G65 standard with different characteristics of abrasive particles such as size (67-245 $\mu$m), shape (round and angular) and hardness (Silica, Alumina and SiC). The rate of changes in the wear is explained based on the observed wear micro-mechanisms of the worn surface. The wear micro-mechanism and associated surface damage were characterized by SEM-EDS and 3D white-light interferometer. Special focus was made on characterizing the circularity and roundness factor to correlate the engagement and wear pattern made by the abrasive particles. The present study has developed new insight into the wear resistance property of cermets against different abrasive characteristics and provides a better understanding of the transition of wear micro-mechanisms during three-body abrasive wear

Abrasion test facilities: a review

Prediction of abrasion resistance with increased accuracy is essential to precisely estimate the operating life of a component. It has always been an intriguing challenge, as the wear results from laboratory testing and real time operations are widely mismatched, especially due to the dearth of suitable and reliable testers. There is a need to bridge this gap by developing apt testers with enhanced dependability and improved predictability. A concise review of over 100 papers was performed and testers based on the standards like ASTM G99, G132 or G65 were mostly used. The abrasion test facilities have been broadly classified into four categories based on the testing aspects viz., type of abrasion (two- / three body), contact kinematics (sliding/rolling/reciprocating/impact), contact medium (dry/wet/slurry), and customized abrasion testers. The noteworthy observations to be mentioned are; firstly the existence of a number of standard, non-standard as well as customized testers. Secondly, only few standards prescribe the relevance of test facility to a particular end-application. Lastly, there exists a lack of clear understanding of the interdependencies between the test facilities and even if it exists, is inconclusive. The vital reflection from the study is the existence of a missing link in connecting the laboratory test parameters to the real operating conditions or vice versa. The task of development of this vital link is the fundamental foundation for the future work

Wear mechanisms prevalent in agricultural tines

The wear of soil engaging tools is of high importance considering the required increase of agricultural produce to meet the growing population. Considering wear studies, the wear mechanism is the key factor to equate between wear parts and labscale coupon specimens. In the present investigation symmetrical skew wedge tines were considered for investigation. An in-field test was performed for the wear investigation. Subsequently, the tines were investigated for wear mechanism, linear dimensional change and mass loss. It is evident from the investigation that the mass loss of the tine follows a linear trend as a function of ploughing distance. The thickness reduction and also the tip length of the tine shows a running-in behaviour. One of the important finding is that the linear dimensional losses are larger than the thickness losses which indicate the priority to study the wear mechanisms prevalent on the cutting side. Furthermore, two different micro-mechanisms were prevalent in the cutting side (micro-cutting and micro-ploughing). An segment specific map based on the different micromechanism is drawn for the investigated tines