The Embrittlement of Blackheart Malleable Iron
1981 Volume 67 Issue 2 Pages 391-398
Details
1981 Volume 67 Issue 2 Pages 391-398
An investigation has been made of the effect of cooling rate from both 450 and 650°C and also the effect of treatments consisting of various combination of heating rate, holding temperature and cooling rate on the shift of transition temperature of blackheart malleable iron by impact test. IMA analysis has been also carried out on the fracture surface of specimens cooled from 450°C under the various cooling conditions.
The results obtained are as follows:
(1) Holding at 650°C or slow cooling from 450°C shifts the transition temperature to lower temperatures.
(2) Q uenching from 450°C increases the tendency of embrittlement.
(3) Any heat treatment have no effect no the transition temperature when cooled from 650°C after 0.5 h. holding.
(4) The influence of cooling fate from 650°C to room temperature on the embrittlement of blackheart malleable iron is almost the same as that in the temperature range from 650°C to 450°C.
(5) IMA analysis on the fracture surface of blackheart malleable iron cooled from 450°C with various cooling rate shows that the larger the cooling rate is, the higher the phosphorus concentration on the fracture surface becomes.
