Failure Analysis of Wire Ropes Used in Multi-Wire Machines for Cutting Blocks of Stone

ABSTRACT: This paper reports the analyses carried out with the company Pedrini SpA ad unico socio, located in Carobbio degli Angeli, Bergamo (IT). Wire ropes with diamond beads, used as cutting tools in multi-wire machines for cutting blocks of stone, were considered and a failure analysis of the wire ropes was carried out. The aim of the paper is to highlight the damage mechanisms of the wire ropes to increase service life of these cutting tools. Microscope observations and the penetrating liquids method were used to analyze the damaged wire ropes. Fatigue, corrosion and contact fatigue problems were observed and the effect of the centering of the beads on the wire rope was studied.

Application prospect of impregnating compounds for maintenance of suspension components of road machines under different temperature conditions

The application possibility of impregnating compounds for maintenance of rubber components of a pneumatic suspension of road machines under different temperature conditions has been assessed. Solid oil (the cheapest general-purpose plastic grease) and anaerobic material of AN-1U grade (richer impregnating compound) were used as impregnating compounds. It was found out that the use of impregnating compounds for maintenance of rubber components of a pneumatic suspension of road machines made possible to increase their resistance to the effect of negative temperatures, to minimize material cracking and as a result to increase service life of the suspension.

New Evidences which Support Existence of the Forced Heat Exchange Phenomenon

In the paper the forced heat exchange phenomenon is validated based on experimental data shown by different authors in different countries and published in respected scientific journals. Software IQLab and regular thermal condition theory were used for solving inverse problems. The data of silver and copper spherical probes quenching in electrolytes were used. As in previous publication, it was established in the paper that heat transfer coefficients (HTCs) increase versus time during quenching of silver and copper probes in electrolytes. As noted early, all of this contradicts the theory of transient nucleate boiling processes. The problem is solved by periodical replacement of film boiling by shock boiling with the high frequency that takes place during quenching. The new idea can be used in practice for designing new and original quenching technology to save materials, increase service life of machine components and also provide an environmentally friendly solution. The importance of new technologies is widely discussed in the paper.

Some Comments on Fatigue Life Tests of Aircraft Cable Control Systems

Cable control systems are widely used in aircraft and gliders. This paper deals with the problem of collecting real loads acting cable control systems and cable tests preparation (load spectrum) and performance. The author proposes a method for defining real loads acting on control systems, preparing and carrying out fatigue tests of cables revealing symptoms of fretting. The fatigue tests results can be used to predict service life, to plan and prepare periodic and details inspections. This method could be used to increase service life of aircraft control cables and could help to replace the commonly used Time-Based Maintenance (TBM) strategy with the Damage Tolerance (DT).

Achievements and Prospects of Functional Pavement: Materials and Structures

In order to further promote the development of functional pavement technology, a Special Issue of “Achievements and Prospects of Functional Pavement” has been proposed by a group of guest editors. To reach this objective, articles included in this Special Issue are related to different aspects of functional pavement, including green roads to decrease carbon emission, noise, and pollution, safety pavement to increase skid resistance by water drainage and snow removal, intelligent roads for monitoring, power generation, temperature control and management, and durable roads to increase service life with new theory, new design methods, and prediction models, as highlighted in this editorial.

IMPROVING WORK RESOURCE OF SAFETY EQUIPMENT FOR EUTECTIC COATING

Today, in Ukraine, fire-fighting and rescue units in the event of fires and emergencies of a natural and anthropo-genic nature are often forced to operate emergency life-saving tools and equipment that are partially worn or outdated. It is extremely costly to completely replace the equipment of all fire and rescue units. Therefore, the development of methods for the restoration of worn or partially worn parts of fire and rescue equipment, as well as increasing their service life and interrepair interval, is an urgent task for today.The proposed work is devoted to the application of eutectic coatings based on the Fe-Mn-C-B-Si alloy Cr system for the restoration of partially wornout steel parts of firefighting equipment and rescue equipment, as well as to increase the service life (lifetime) of these parts. The essence of the experimental study was to compare the wear of the cutting elements of hydraulic emergency rescue scissors "Hydrum H-32" series production and scissors with a protective eutectic coating. The work life of the eutectic coatings of Fe-Mn-C-B-Si doped Cr working bodies of emergency rescue scissors in 1.8 times greater than that of working bodies of serial production, so it is advisable to repair such worn parts of the rescue and fire tool. Due to the relatively low cost of eutectic alloys based on iron, this method is economically viable as an alternative to replacing parts with new ones. This type of coating can also be applied to other steel parts of fire-fighting and rescue equipment to restore worn parts and increase service life and overhaul intervals. The use of durable eutectic iron based coatings is economically feasible given their relatively low cost.

Hartwalzen von Lagerringen zur Lebensdauersteigerung/Hard rolling of bearing rings to increase service life

Zur Steigerung der Lagerlebensdauer von Hybridwälzlagern hat das Fraunhofer Institut für Produktionstechnologie IPT gemeinsam mit Cerobear GmbH, Hegenscheidt-MFD (A Member of the NSH-Group) und Schmitz-Metallographie GmbH an der Qualifizierung und Implementierung des Verfahrens Hartwalzen in die Prozesskette zur Herstellung von Hybridwälzlagern gearbeitet. Durch die Induzierung von Druckeigenspannungen in die Lagerlauffläche konnte die Lebensdauer nachweislich erhöht werden. Die Arbeiten wurden im Rahmen des geförderten Forschungsvorhabens „Hartwalzen von Lagerringen“ durchgeführt, das aus Mitteln des europäischen Fonds für regionale Entwicklung (EFRE) gefördert wurde.   To increase the service life of hybrid rolling bearings, the Fraunhofer Institute for Production Technology IPT together with Cerobear GmbH, Hegenscheidt-MFD (A Member of the NSH Group) and Schmitz-Metallographie GmbH successfully qualified and implemented the hard rolling process in the process chain for manufacturing hybrid rolling bearings. By inducing residual compressive stresses in the bearing running surface, the service life has been demonstrably increased. The work was carried out as part of the funded research project „Hard Rolling of Bearing Rings“, which was supported by the European Regional Development Fund (EFRE).

FORCE CONDITIONS OF TRANSITION TO ONE-ZONE PROCESS OF BACKWARD SLIP DURING COLD ROLLING OF STRIPS

Results of analytical researches of power parameters of cold rolling of thin and average steel strips with a back tension are presented. Considerable decrease in average relative tension on a surface of contact with rolling rolls upon transition is established from two-zonal to one-zonal rolling of lag. It allows to increase service life of rolling rolls.