Abstract
In investigating the cementation of pure iron and the decarburisation of carburised high carbon steels, a dilatometer, which is capable of varying freely the inner atmosphere, was employed. Thin tubular specimens 8mm in outer diameter, 0·75mm in wall thickness and 100mm in length taken as standard, were heated at certain constant temperatures for a long duration in a tubular heat resisting carburising box, in which solid carburising materials were placed or gas current applied. Since austenite increases remarkablely in volume as the cementation proceeds, an l contracts by the decarburisation, the stages of various changes accompanied with these phenomena were precisely traced under various conditions in the carburising box, by measuring the dilatation of the specimens.
The contents of the present paper are as follow:-
I Intro luction.
II Apparatus of experiment.
III Samples and experimental methods.
IV Preliminary experiments.
V Cementation of pure iron by solid carburising materials.
A Promoting action of BaCO3 upon cementation.
1 Effect of ratio of BaCO3 to charcoal
2 Heating time and cementation degree.
3 Cementation by repeated heating and cooling.
4 Cementation by various carbons.
5 Grain size of carburising materials and cementation power.
6 Cementation in vacuum and effect of air upon cementation.
7 Temperature and cementation effect.
B Promoting action of other carbonates upon cementation.
a Action of SrCO3.
b Action of Na2CO3.
c Action of CaCO3 and MgCO3.
C Moisture in the carburising materials and cementation power.
VI Saturated cementation of iron.
1 Implication of saturated cementation.
2 Quenching tests.
VII Decarburisation of carburised high carbon steels.
1 Decarburisation in solid carburising materials.
2 Decarburisation in gas current.
3 Cementation of the soft steel and decarburisation of the carburised steel.
VIII Summary.
IX References.
