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1

Conical Picks for Undeground Mining

Bołoz Łukasz

New Trends in Production Engineering

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2020

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Vol. 3, Iss. 1

221--230

EN

Mechanical cutting in underground mining faces increasingly difficult challenges. Deteriorating working conditions result in the development of automation and robotization, and the insufficient durability of cutting tools remains a serious problem. In addition to drilling, the technology of cutting provides a huge market for tools. Currently, mainly conical picks are used in the process of cutting. The cutterheads of shearers are equipped with at least several dozen conical picks, which, due to their workability and abrasiveness, sometimes work for merely a few hours. Hence the interest of users and manufacturers in the development of tools with increased durability. The article briefly presents the applied solutions of conical picks, their construction, dimensions and materials used. Attention was paid to the issues related to the protection applied and its marking. A review and analysis of commonly known construction solutions for picks and holders have also been carried out, and proprietary patent pending solutions for the pick and holder have been presented.

2

Sposoby zwiększania trwałości noży styczno-obrotowych

Bołoz Łukasz

Przegląd Górniczy

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2019

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T. 75, nr 9

28--34

PL

Noże styczno-obrotowe są to narzędzia skrawające stosowane w wielu branżach, zwłaszcza górniczej, drogowej i budowlanej. Kontakt z urabianą calizną powoduje ich ciągłe zużycie. W artykule omówiono rozwiązania konstrukcyjne noży styczno-obrotowych, ich budowę, wymiary oraz stosowane materiały. Opisano zabiegi techniczne stosowane w celu zwiększenie ich trwałości, jak również regeneracji. Omówiono również autorskie, objęte zgłoszeniem o patent na wynalazek, sposoby wydłużenia czasu pracy noży w trudnych warunkach. Pierwsze z tych rozwiązań dotyczy zapewnienia niezakłóconego ruchu obrotowego noża w uchwycie. Zastrzeżenia patentowe obejmują nowatorskie łożyskowanie obrotowe dodatkowej tulei zintegrowanej z uchwytem, która umożliwia ciągły obrót noża. Uchwyt przeznaczony jest do mocowania klasycznych noży handlowych. Wymiana noża odbywa się bez ingerencji w węzeł łożyskowy. Drugie rozwiązanie dotyczy sposobu zabezpieczenia części roboczej noża za pomocą specjalnego elementu z materiału trudnościeralnego. Element ten stanowi ostrze noża o geometrii odbiegającej od standardowo stosowanych słupków z węglików spiekanych. W rozwiązaniu tym ostrze ma kształt odpowiadający formie zużycia noża styczno-obrotowego, przez co jego stalowy korpus nie zużywa się.

EN

Conical picks are cutting tools used in many branches, in particular in the mining, road construction and building branch. Contact with the excavated face causes their constant wear, which is an unfavourable but unavoidable process. In the article various solutions of conical picks, their construction, dimensions and materials used have been discussed. Technical procedures applied to increase the durability of conical picks and their regeneration as well as methods of extending the life of picks working in difficult conditions have been presented. Two author’s methods of extending the life of picks working in difficult conditions, covered by a patent application, have also been presented. The first solution involves ensuring an uninterrupted rotational movement of the pick in the holder. Patent claims include an innovative method of equipping the additional sleeve integrated with the holder with a rotational bearing, which enables a continuous rotation of the commercial pick. The pick replacement does not require interfering with the bearing assembly. The second solution concerns the manner of protecting the working part of the pick by means of a special element made of an abrasion resisting material. This element is the pick tip, the geometry of which varies from the commonly applied posts made of sintered carbide. In this solution, the tip has a shape corresponding to the form of conical pick’s wear, which causes that its steel body does not wear.

3

Directions for increasing conical picks’ durability

Bołoz Łukasz

New Trends in Production Engineering

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2019

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Vol. 2, Iss. 1

277--286

EN

Conical picks are cutting tools used in many branches, in particular in the mining, road construction and building branch. Contact with the excavated face causes their constant wear, which is an unfavorable but unavoidable process. Milling heads of working machines are equipped with several dozen conical picks, and mining in abrasive or hardly accessible rocks can reduce their life to a few hours. It is in the interest of both users and producers to increase their durability, as tools replacement, apart from purchase and logistic costs, results in machine downtimes. In the article various solutions of conical picks, their construction, dimensions and materials used have been discussed. Technical procedures applied to increase the durability of conical picks and their regeneration as well as methods of extending the life of picks working in difficult conditions have been presented. Two author’s methods of extending the life of picks working in difficult conditions, covered by a patent application, have also been presented. The first solution involves ensuring an uninterrupted rotational movement of the pick in the holder. Patent claims include an innovative method of equipping the additional sleeve integrated with the holder with a rotational bearing, which enables a continuous rotation of the pick. The tool equipped with a bearing generates much lower movement resistance than the standard mounting. The holder is designed to mount classic commercial picks. What is important, the pick replacement does not require interfering with the bearing assembly. The second solution concerns the manner of protecting the working part of the pick by means of a special element made of an abrasion resisting material. This element is the pick tip, the geometry of which varies from the commonly applied posts made of sintered carbide. In this solution, the tip has a shape corresponding to the form of conical pick’s wear, which causes that its steel body does not wear. Moreover, there is a possibility of applying a mobile, rotational mounting of the tip to the body.

4

The Use of 3D Scanning Methods to Evaluate the Hybrid Layer Used in Forging Tools in Order to Improve their Durability

Gronostajski Z., Hawryluk M., Kaszuba M., Widomski P., Ziemba J., Smolik J.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 3

1549--1558

EN

This study is focused on tools used in the industrial process of hot forging of a front wheel forging (gear wheel) manufactured for the automotive industry. Five different variants were applied for the tools: 3 die inserts were coated with three different hybrid layers (PN + PVD type), i.e. AlCrTiN, AlCrTiSiN and CrN, one insert was only nitrided, and one was pad welded, to improve tool durability. The tool wear was analysed and represented by the material degradation on the working surface, based on the 3D scanning and the material growth of the periodically collected forgings. Additionally, the scanned tools were divided into two areas, in which it was found, based on the analysis, that various degradation mechanisms are predominant. Microstructural tests and hardness measurements of the analyzed tools were also performed. Based on the results, it was found that, in the central part of the die insert, thermo-mechanical fatigue, abrasive wear and plastic deformation occurred, while in the area of the bridge insert, only abrasive wear could be observed. For these areas, the loss of material was determined separately. It was established that the use of the GN+CrN and GN+AlCrTiN hybrid layers on forging tools improves their durability, while the best results in the central area were observed on the tool with the GN+CrN layer, which is the most resistant to thermo-mechanical fatigue. In the second analyzed area, good wear resistance occurred on GN+CrN, GN+AlCrTiN and pad welded inserts, for which, together with the increase of the forging number, a proportional, slight growth of the loss of material occurred.

5

Chemical-heat treatment of materials used for fabrication of tools and effects of this treatment to durability of tools

Němec J., Fajt J.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 62, nr 2

88--92

EN

Purpose: The aim of the presented researches is development and design of fluid bed mixed by hot gas. The fluid bed is designed to the chemical-heat treatment with thermo-active powders. This treatment is used for tools and mechanical parts. Design/methodology/approach: Contribution is focused on increasing of the cutting property of tools made from high speed steel by chemical-heat treatment. Precisely nitrocarburizing at a fluid mixture of a thermo-active powder was used. Possibilities of this method of nitrocarburizing are described in the contribution, especially advantages, disadvantages and effects on the durability of the tools and mechanical parts. Findings: The material test have showed that the surface layer made by fluid process have better properties than layers made by classical method. But the verification test of the tools with nitrocarburizing did not show increasing of durability. Research limitations/implications: Layer of nitrocarburizing was evaluated by material tests as nanoindentation and scratch-test. Moreover working test of the tools and parts was made for detection of the effect of the fluid-nitrocarburizing to the durability of the tools and properties of the parts. Originality/value: The chemical-heat treatment with fluid bed extends durability of thermo-active powders against treatments without fluidization. Other advantage of the treatment with fluidization is reducing of the energy consumption of the technological process.

6

Zastosowanie warstw hybrydowych na narzędziach do kucia na gorąco odkuwki koła czołowego

Gronostajski Z., Kaszuba M., Hawryluk M., Będza T., Włodarczyk W., Smolik J.

Prace Naukowe Politechniki Warszawskiej. Mechanika

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2013

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z. 253

101--106

PL

W pracy przedstawiono opis zjawisk zachodzących na powierzchni matryc do kucia na gorąco odkuwki koła czołowego, gdzie w celu poprawy ich trwałości zastosowano warstwy hybrydowe. Analizie poddano narzędzia wykonane ze stali WCLV stosowane w drugiej operacji kucia. Oceniono skuteczność zastosowanych warstw hybrydowych w zwiększaniu trwałości analizowanych narzędzi. Przeprowadzone badania wykazały, że modyfikowanie właściwości warstwy wierzchniej przez zastosowanie technik hybrydowych typu warstwa azotowana i powłoka PVD daje możliwość efektywnego zwiększenia trwałości narzędzi kuźniczych w analizowanym procesie.

EN

The article presents a description of the phenomena occurring on the surface of dies with hybrid layer for hot forging of front wheel. Analysis was carried out on the tools made of steel WCLV used in the second operations. The effectiveness of the hybrid layer for improving the durability of analyzed tools has been evaluated.

7

About possibility of improving durability of metal forming tools by ion implantation

Tarkowski P., Łukasik K., Budzyński P., Liśkiewicz J.

Nukleonika

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1999

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Vol. 44, nr 2

247-252

EN

In this paper the authors have shown the results of comparative industrial research on the durability of punches used to pierce nuts produced in the standard way, through ion implantation or after complex treatment. Nitrogen ions with the energy of 120 KeV at a dose of 2x1017 ions/cm2 were used. A relative increase in the durability of the N+ implanted nuts was observed, which was about 1.5 in comparison to the other types of punches.

PL

W pracy przestawiono rezultaty przemysłowych badań porównawczych trwałości stempli do przebijania otworów w nakrętkach, w wykonaniu standardowym, implantowanych jonowo i po obróbce kompleksowej. Do implantacji wykorzystano jony azotu o energii 120 keV i dawce 2x1017 jonów/cm2. Stwierdzono względny wzrost trwałości stempli implantowanych jonowo wynoszący około 1.5 w stosunku do stempli pozostałych rodzajów.