Initial Assessment of Abrasive Wear Resistance of Austempered Cast Iron with Vermicular Graphite

Abstract

The work compares the abrasive wear resistance of cast iron containing vermicular graphite, measured in the as-cast state and after austempering carried out at 290• C, 340• C, or 390• C. The examinations were performed by means of the T-01M tribological tester using the pin-on-disc configuration. Specimens used for examinations were taken from the end tabs of the tensile specimens, these being cut out of the test walls of the double-leg keel block test castings. Examinations proved that the austempering process increases the abrasive wear resistance of vermicular cast iron by several times as compared with the as-cast material. A tendency for a slight decrease in abrasive wear with an increase in austempering temperature can be stated. The coefficient of friction took a little higher values for cast iron after thermal treatment than for the as-cast material. The work was completed with roughness examination by means of electron scanning microscopy.Keywords: cast iron, vermicular graphite, austempering, abrasive wear resistance W pracy porównano odporność na ścieranie żeliwa z grafitem wermikularnym w stanie lanym oraz po hartowaniu izotermicznym przeprowadzonym w temperaturach 290• C, 340• C i 390 • C. Badania odporności na ścieranie przeprowadzono przy użyciu zestawu trybologicznego T-01M typu trzpień-tarcza. Próbki do badań pochodziły z próbek wytrzymałościowych wyciętych ze ścianek badawczych wlewków próbnych w kształcie odwróconej litery "U". Badania wykazały, że poddanie żeliwa wermikularnego hartowaniu izotermicznemu prowadzi do kilkukrotnego wzrostu odporności tworzywa na ścieranie w porównaniu z żeliwem w stanie lanym. Zaobserwowano niewielki spadek zużycia wraz ze wzrostem temperatury hartowania. Współczynnik tarcia dla żeliwa po obróbce cieplej przybrał nieco większe wartości aniżeli w przypadku żeliwa w stanie lanym. W ramach pracy wykonano także badania chropowatości z wykorzystaniem mikroskopii skaningowej.

Effect of Copper on the Crystallization Process, Microstructure and Selected Properties of CGI

“…Because of the very interesting complex of properties offered by this kind of cast iron it is the object of intensive research and numerous publications [1][2][3][4][5][6][7][8]. There is a fairly large group of publications describing the opportunity of various types of the acicular microstructure obtainment [9][10][11][12].…”

Approximation of Ausferrite Content in the Compacted Graphite Iron with the Use of Combined Techniques of Data Mining

“…By changing the chemical composition, it is possible to modify to a large extent the cast iron microstructure and consequently its properties. There are numerous publications describing the possibility of obtaining ausferrite in compacted graphite iron, to produce next AVI (Austempered Vermicular Iron) or CAVI (Carbidic Austempered Vermicular Iron) [5,6]. Ausferrite is a mixture of bainitic ferrite and carbon-saturated austenite.…”

Nickel in Compacted Graphite Iron

“…The potential of the cast iron still seems to be not fully exploited. It is demonstrated by the number and the exceedingly wide range of studies concerning different types of the cast iron [2][3][4][5][6][7][8]. A special position among all kinds of the cast iron occupies a compacted graphite iron (CGI).…”