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Research on the effect of temperature increase during flow forming without cooling on 6060 aluminum alloy

Gądek Tomasz, Majewski Marcin

Materials Science Poland

2023

Vol. 41, No. 3

74--84

This paper presents the results of flow forming tests for the 6060 aluminum alloy in the T5 heat treatment condition. The tests were conducted on a cylindrical mandrel using two forming rollers without the use of a cooling agent. The purpose of the study was to conduct two experiments. In both experiments, the final gap between the roller and the mandrel was designed to be the same. The impact of the deformation value on the change in the mechanical properties of the material with the simultaneous impact of the number of forming passes was determined. In addition, the effect of the elimination of a coolant on the process was analyzed. The material temperature rise caused by friction between a pair of working parts: the roller—and the workpiece—were examined with a thermal imaging camera. This paper presents the results of microhardness tests and analyzes the impact of the forming parameters on the strength properties of the alloy. Because the forming process was done without cooling, the impact of the temperature prevailing during the deformation process on the change in the strength of the alloy was studied and analyzed. The deformation zone in which intensive grain deformation took place was determined.

Ocena efektywności smarów plastycznych w aspekcie ich zastosowania w procesie głębokiego tłoczenia blach

Krawiec S., Krawiec M.

Tribologia

2005

nr 4

147-155

W artykule przedstawiono badania tribologiczne dwóch smarów plastycznych (smaru maszynowego i Litomosu EP-25) przeprowadzone pod kątem oceny ich zdolności do pełnienia funkcji smaru technologicznego. Badania efektywności tych smarów przeprowadzono w dwóch etapach. Etap pierwszy obejmował wyznaczenie wskaźników efektywności na podstawie testów wykonanych na aparacie czterokulowym z kulkami o twardości modelującej twardość matrycy i tłoczonej blachy. Jako kryteria efektywności przyjęto obciążenie zespawania, zużycie i wskaźnik granicznego obciążenia zużycia. W etapie drugim przeprowadzono testy na prasie w sztywnej matrycy używając stempla o średnicy = 190 mm. Tu kryterium efektywności smaru była głębokość i maksymalna siła tłoczenia.

A paper presents results of tribological tests of two plastic greases (a machine grease 2 and Litomas EP - 25) carried - out in order to estimate their ability to perform the function of the technological grease in the process of deep sheet - metal stamping. The tests of the greases effectiveness have been realized in two stages. The first stage comprised determination of the effectiveness factors basing on the tests conducted on four - balls apparatus with the balls of the hardness modeling the hardness of both the die and the metal sheet. The rotating ball was hardened to 62 HRC while stationary balls to 240 HB. The following factors were assumed as the effectiveness criteria: welding load FZ, wear rate of the stationary balls d and the indicator of the limiting wear load Goz. In the second stage the tests were carried - out by means of hydraulic press with the load of 2000 kN. The samples were in the form of rollers being stamped in the rigid die by the punch of diameter 190 mm. The samples were produced from the car body sheet E220BH with thickness of 0,75 mm. Here, the effectiveness criterion was depth and maximal stamping force as well as the surface outlook of the drawpiece. It has been found that the welding load FZ was equal to 450 daN and that it is by 120% bigger when compared to the force found for the machine grease. The similar differences occurred during the stamping trials. Destruction of the samples, in the presence of the machine grease, occurred on the depth of 24 mm, that is about 9 mm greater as without grease. It was easy to stamp the samples without the traces of destruction on the full depth of 69 mm at the presence of Litomas grease. The results to be found allow to conclude that the effectiveness of the plastic grease estimated on the four - balls apparatus with the balls modeling the die and metal sheet hardnesses does not differ essentially from that determined in the process of deep stamping. However, this statement necessitates, due to the small number of the greases as well as due to neglecting variation of p, v parameters, further tests.