Ledeburite

Ledeburite designated certain eutectic structure of the iron -carbon alloys. It was named after its discoverer, the metallurgist Karl Heinrich Adolf Ledebur (1837-1906), named.

Ledeburite occurs with a carbon content between 2.06 percent and 6.67 percent ( line ECF in the iron -carbon diagram). The carbon content of the eutectic mixture is 4.3 percent, the melting temperature is 1147 ° C ( eutectic point C). In this carbon concentration is present 100 percent ledeburite in the microstructure.

Ledeburite is not a phase, it is a phase mixture consisting of ( crumbled ) austenite and cementite. A distinction is made between ledeburite I and II ledeburite. While it is ( just below 1147 ° C) is a microstructure of austenite and cementite at ledeburite I, the ledeburite consists II (room temperature) of cementite with ankristallisiertem secondary cementite ( from the austenite with decreasing temperature excreted ) and ( with slow cooling ) of perlite. The pearlite is formed by the eutectoid decomposition of austenite from the ledeburite I at 723 ° C. For more rapid cooling may be in place of perlite and bainite or martensite at very rapid cooling.

• Materials Science