STRENGTH OF INSERTS MADE OF HARD AND SUPERHARD MATERIALS UNDER WEDGE CLAMPING ACTION

Simulation of wedge clamping action on cutter bit inserts is carried out on a test bench for tool materials. In the tests, cutter bits were placed between tungsten carbide inserts simulating wedge clamping. The pressing device to initiate destruction of the test inserts is described. One half of a cutter bit is clamped under the pressing force in the range of 250–7500 kN while the other half of the bit is subjected to loading until failure. The critical stresses after static treatment are given in the tables. The strength of the inserts made of VK6 hard alloy, CBN and nanocomposites MBR6010 and MBR7010 is plotted versus the clamping pressure. The behavior of strength of the latter materials was studied poorly in view of their unavailability due to high cost. However, it is found that the CBN inserts exhibit low strength even under the clamping force below the standard value of reliable operation of the wedge clamp. The strength curve of the hard alloy inserts has the peak value at the clamping pressure of 200 MPa. Under the pressure up to 200 MPa, the strength grows with the increasing clamping pressure and failure takes place in the clamping zone. After the peak value, VK6V insert strength drops and, then, the strength curve flattens. This strength behavior of VK6V inserts under the varied clamping pressure is explained. The conclusion is drawn that the wedge clamping pressure for the non-operating parts of tungsten carbide inserts or two-layer inserts with tungsten carbide base should be not higher than 200 MPa.

Keywords

Strength, MBR6010 and MBR7010 nanocomposites, wedge clamping, inserts, hard allow, clamping pressure, detachable fixing.

Issue number: 12
Year: 2018
ISBN:
UDK: 622.23.051; 620.171.2:669.15
DOI: 10.25018/0236-1493-2018-12-0-142-150
Authors: Fedorov L. N., Ermakov S. A.

About authors: Fedorov L.N.,Researcher, e-mail: lnfedorov@mail.ru, Ermakov S.A., Candidate of Technical Sciences, Senior Researcher, Head of Laboratory Chersky Mining Institute of the North, Siberian Branch, Russian Academy of Sciences, 677018, Yakutsk, Republic of Sakha (Yakutia), Russia.

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