Únavové vlastnosti ADI v závislosti na době izotermické prodlevy

Fatigue Properties of ADI in Dependence on Isothermal Transformation Dwell

článek v časopise - ostatní, Jost

en

As a result of excellent both mechanical and technological properties, austempered ductile iron (ADI) is ranked with very perspective sturcutral materials. Recently it has been aplied even to castings for dynamically loaded components and a considerable part of ADI production is applied also in military industry. The structure of ADI matrix, mostly created by the micture of bainite and stabilized austenite strongly depends on transformation conditions, i.e. temperature and the length of isothermal transformation dwell. An ADI transformed at 380°C during a temporal range from 2 minutes to 9 hours was studied in details, with emphasis on structural composition and fatigue properties The highest level of fatigue properties was obtained for the transformation dwell of 60 min. when the maximum portion of austenite was found in ADI structure.

Díky svým výborným mechanickým i technologickým vlastnostem se ADI řadí mezi velmi perspektivní strukturní materiály. Nedávno začala být používána pro dynamicky namáhané součásti také ve zbrojním průmyslu. Struktura ADI sestává z bainitu a zbytkového austenitu a velice závisí na podmínkách izotermické transformace t.j. teplota a doba. V tomto příspěvku byla studována ADi transformovaná při teplotě 380°C dobou izotermické prodlevy v rozsahu od 2 min do 9 hodin. Byl studován vliv délky izotermické prodlevy na složení strukturní směsi a únavové vlastnosti. Nejvyší hodnota meze únavy byla dosažena po 60 min izotermické transformace kdyz byl ve struktuře zjištěn maximální obsah stabilizovaného austenitu.

As a result of excellent both mechanical and technological properties, austempered ductile iron (ADI) is ranked with very perspective sturcutral materials. Recently it has been aplied even to castings for dynamically loaded components and a considerable part of ADI production is applied also in military industry. The structure of ADI matrix, mostly created by the micture of bainite and stabilized austenite strongly depends on transformation conditions, i.e. temperature and the length of isothermal transformation dwell. An ADI transformed at 380°C during a temporal range from 2 minutes to 9 hours was studied in details, with emphasis on structural composition and fatigue properties The highest level of fatigue properties was obtained for the transformation dwell of 60 min. when the maximum portion of austenite was found in ADI structure.

fatigue properties, ADI, isothermal transformation, transformation dwell.

01.02.2004

1335-4205

Communications

2004

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