144 Proceedings of Indiana Academy of Science 



Small blocks were cut from a bar of ordinary commercial high 

 carbon steel of the following composition; carbon, 1.2; manganese, 

 0.30; phosphorus, 0.02; sulphur, 0.03; silicon, 0.20 per cent. 



The method of preparing these specimens was the same as previously 

 used in the study of inclusions in low carbon steel. This consisted in 

 drilling holes through the blocks. At the same time rods of several 

 alloys and special steels were turned on the' lathe to a diameter slightly 

 larger than the holes. After cleaning both rods and holes with an 

 alcohol ether mixture the rods were driven into the holes and hammered 

 until the contact between the two pieces was very intimate. 



The alloy or special steel insert now occupied the same relation to the 

 main body of high carbon steel as a natural inclusion might occupy 

 in the same position. 



The specimens so prepared were heated well above the transforma- 

 tion range of the steel for varying periods of time after which they 

 were allowed to cool slowly in the furnace. After this treatment a 

 section was cut from each specimen perpendicular to the axis of the 

 insert so that the zone about the contact between it and the main body 

 of the piece might be subjected to examination for evidence of cementite 

 segregation. 



In order to study in a more definite manner the effect upon carbon 

 distribution produced by the localization of a few of the more common 

 elements generally found in ordinary commercial steels inserts were 

 made of several specially prepared steels. 



Number 1 was a plain carbon steel containing about 0.5 per cent 

 carbon. The other seven were of identical composition except that to 

 each had been added some element in excessive amount. For example 

 to number 2 had been added silicon and to number 3 phosphorus, etc. 

 The amount of the added element found in each of the entire set follows: 



No. 1 Plain 0.5 per cent carbon steel. 



No. 2 Plain 0.5 per cent carbon steel plus 4.0 9^ silicon. 



No. 3 Plain 0.5 per cent carbon steel plus l.O&^r phosphorus. 



No. 4 Plain 0.5 per cent carbon steel plus 1.46% manganese. 



No. 5 Plain 0.5 per cent carbon steel plus 1.34'% copper. 



No. 6 Plain 0.5 per cent carbon steel plus 0.84 7r chromium. 



No. 7 Plain 0.5 per cent carbon steel plus titanium. 



No. 8 Plain 0.5 per cent carbon .steel plus 1.36% sulphur. 



Several non-ferrous alloys al.o vvere uced for insert.^. Among them 

 v\ere alumel, an alloy of aluminium and nickel; copel, an alloy of copper 

 and nickel; and chromel, an alloy of chromium and nickel. 



The specimen with the insert of plain carbon steel and which 

 contained no excessive amount of any element showed no tendency to 

 cause the separation of cementite. It was found however that the dif- 

 fusion from some of the other inserts into the adjacent steel had a 

 tendency to cause cementite to segregate in this region while with other 

 inserts containing other elements this tendency did not manifest itself 

 under the conditions of the experiment. A few photomicrographs will 

 show the nature of this effect. 



