Marius BĂRĂIAN Gabriel BATIN

34-40 PRODUCEREA BILELOR MICI

Această intrare a fost publicată în 2018 Volumul 34 și etichetată George ARGHIR Ioan TĂUT Liviu BRÂNDUŞAN Marius BĂRĂIAN Gabriel BATIN Nicu Marian TRANDAFIR la de

MAKING SMALL SPHERES
The mill for the production of small balls, of hard and semi hard material contains as a main part a ring covered with the abrasive material (glued) on the abrasion surface. The ring has the vertical axis. The abrasive surface is made by gluing with glue that softens by heating. The moving of spherical material is made with compressed air, rotating in the grinding space, motion imprinted on the diffuser air. Compressed air comes through the center of the mill through a circuit with minimal aerodynamic resistances. Air pressure: 1 – 2 bar. Ball size: 1 mm. The grinding space has a 7 (horizontal) x 6 (vertical) mm section with an (average) length of 162 mm. The used raw material has cubic shape with a 30 % greater edge than the ball diameter.
Keywords: small spheres, technology, hard and half hard materials
Cuvinte cheie: sfere mici, tehnologie, materiale dure și semidure

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32-37 CONTACTE ELECTRICE CU DENSITATE RIDICATĂ PENTRU CURENŢI INTENŞI PRODUSE PRIN METALURGIA PULBERILOR

Această intrare a fost publicată în 2017 Volumul 32 și etichetată Adrian ARDUSĂTAN Alina Georgeta JUMOLEA George ARGHIR Ioan PETEAN Liviu BRÂNDUŞAN Marius BĂRĂIAN Gabriel BATIN Nicu Marian TRANDAFIR la de

ELECTRICAL CONTACTS WITH HIGH DENSITY FOR STRONG CURRENTS, MADE BY POWDER METALLURGY

 

Electrical contacts for strong currents by infiltration after sintering, was not satisfactory because the final density is much higher (11,100 kg/m3) and porosity is much lower (10.85 %). The infiltration after sintering contains: powder mixture preparation (W – 52 mass %, Ni – 2 %, Cu – 46 %, zinc stearate – 0,7 %  – 7 g), homogenization, pressing (4,5 MPa), sintering (730 and 780 oC). The green density is almost constant, with an identical porosity of the first after the end of the process (14,28 %). By infiltration the density increased drastically (10,832 kg/m3), its variations were increased also and porosity decreased (at 10.85 %). The attained density is not sufficient for electrical contacts work (11,100 kg/m3), but it is closer. Way to improve density: pressing, sintering, and repressing (10,700 kg/m3).

 

Keywords: sintered electrical contacts, W-Cu

Cuvinte cheie: contacte electrice sinterizate, W-Cu

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