US 2039165 A
Description (OCR text may contain errors)
April 28, 1936. HAYAKAWA 2,039,165
METHOD OF TREATING ALUMINIUM OR ALUMINIUM ALLOY Filed Jan. 17, 1935 IN VEN TOR.
KAZUMA HAVA KAWA BMMQLZ A TTORNEYS.
Patented first. 28, 1936 PATIENT I OFFICE METHOD or TREATING ALUMINIUM on ALUMINIUM ALLOY 1 K'azuma Hayakawa, Hodogaya-ku,
Yokohama, Japan App ication January 17, 1935, Serial No. 2,171 2 Clalm's. (CI. 75-68) The present invention relates to a method of treating aluminium or aluminium alloy which is based on the knowledge that when the gas contained in aluminium or aluminium alloy is liberated by heating them in vacuum, it reacts with aluminium and iron and produces various compounds having high hardness and that said compounds are turned into fine particles by ageing and distributed all over the aluminium or aluminium alloy, thus producing "aluminium or aluminium alloy having high hardness as a whole, characterized by the fact that molten aluminium or aluminium alloy is put into an iron vessel and heated in vacuum for thirty to sixty minutes at a temperature above 900 C., after which the heating temperature is lowered to 500 to 700 C. and hydrocarbon gas is filled in the vessel up to more than 1 atm. and then the material is cooled rapidly.
The object of this invention is to obtain aluminium or aluminium alloy having high hardness simply by considerably increasing the hardness of aluminium or aluminium alloy easily and effectively.
Generally, aluminium solution possesses the property of absorbing a gas very much, so it is made to be able to absorb in a molten state a gas having the volume and at the higher temperature it can absorb the bigger quantity. According to Gwyer (Trans.
Faraday Soc. 1919,-vol. 14, p. 173), the following ases were absorbed:--
Percent Carbon dioxide 3 8 Carbon monoxide 0 9.5
Hydrogen -81 Methane 1 -24.5
Nitrogen 5 -11 Oxy 1.5- 4.5
When the free carbon thus produced comes into contact with aluminium in vacuum, it will produce crystals of A140: at 650 C. On the other 55 hand, aluminium has iron melted thereinto at a high temperature in the presence of hydrogen and produces FeAls. Consequently, hard compounds, namely,FeAla, A140: and A: are dis stributed in aluminium or aluminium alloy at a high temperature and are present therein in a I saturated condition. However, if cooled rapidly, they take an oversaturated condition at the ordinary temperature and then, with the lapse of time, are turned into a fine state and separated from the solid solution. Thus, it is possible to ob- I. tain aluminium or aluminium alloy having high hardness.
Referring to the appended drawing,
Fig. l is a longitudinal elevation of an apparatus employed for carrying out this invention into practice;
Fig. 2, a section cut off along the line II-II of Fig. 1 and Fig. 3, a section showing the condition in which fine crystals of FeAla, AhCa and A: have been distributed in aluminium metal and hardened very high.
I To explain the present method with reference to the accompanying drawing,
In Figure 1, I is an ingot of aluminium or aluminium alloy; 2, an iron vessel, for example, an iron pot; 3, an electric resistance furnace and 4, the part where two flat surfaces are connected together by friction, 8 is a porcelain tube for supporting the lead wire I of said electric resistance furnace 3, said lead wire I being cemented to said tube 6 at its end with Dekotinsky cement.
8 is a water jacket; and 9, an empty chamber to be rendered vacuous or cooled as is necessary. If air is exhausted from tubes l4 and is, closing cocks III, II and i2 and opening a cock i3 and operating an air pump (not shown), the above empty chamber 9 will be rendered vacuous. Reversely, if water is introduced into said chamber 9 from a conduit l6, closing the cock l3 and opening the cooks l0 and I l, and then the filling water is discharged from an exhaust pipe i1 through the cock Ii, it is possible to cool the chamber. I8 is a heat resisting steel plate adapted for preventing the deformation of the furnace wall by reflecting heat. I9 is a heat reflecting'plate consisting of a round heat resisting steel plate having apertures 20 and a heat resisting steel plate of the smaller diameter, combined to form an I-shaped section. It is engaged with the projections 2| of the upa per part of the inner wall of the furnace and is suspended over the iron pot 2. The exhaust of the air in the furnace is effected from a tube I! through the apertures 20 of the heat reflecting plate It by means of an air pump (not shown).
Also, to fill hydrocarbon gas in the furnace, it is introduced into the latter from the tube I! through a tube 22 and the cock i2.
The following is the manner of performing this invention by employing the above apparatus:-
Firstly, closing the cocks III, II and I2 and opening the cock is, exhaust air from both the furnace and empty chamber 9 by an air pump till they become partially vacuous, when the interior of the furnace is heated by the electric resistance furnace 3, and as the empty chamber 9 is at this time in a vacuous state, it prevents the escape of heat from the electric furnace 3. Thus, after melting aluminium or aluminium alloy by heating it in the iron pot 2 for thirty to sixty mihutes by said electric furnace, lower the temperature to 500-700 C. by regulating the voltage of the electric furnace. Then, fill hydrocarbon gas in the furnace up to over 1 atm. through the tube I. from the tube 22 by opening the cock l2. Soon after, opening the cocks l0 and Ii and closing the cocks l2 and i3, introduce cooling water into the empty chamber 9 from the tube II and discharge it from the tube i1, thus cooling said molten aluminium or aluminium alloy rapidly.
The aluminium or aluminium alloy thus obtained having fine crystals of FeAla, AliC: and
aosaios A120: distributed all over them as shown in Figure 3, possesses very high hardness.
In Figure 3, 23 is the outer cylindrical part of an iron vessel having the hardness l0.2 accord ing to Rockwell scale. 20 is the aluminium metal manufactured according to the present invention, the hardness of the diflerent parts of which, when measured with Rockwell scale, has the values as shown in Fig. 3.
1. Method of treating aluminium or aluminium alloy, which consists in heating molten aluminium or aluminium alloy in vacuum in an iron vessel for thirty to sixty minutes at over 900 C., then lowering the heating temperature to 500 to 700 C. and filling hydrocarbon gas in said vessel up to over 1 atm. and subsequently cooling the above material quickly.
2. Aluminium or aluminium alloy having high hardness, which is made by heating molten aluminium or aluminium alloy in vacuum in an iron vessel for thirty to sixty minutes at over 900 C., then lowering the heating temperature to 500 to 700 C. and filling hydrocarbon gas in said vessel up to over 1 atm. and subsequently cooling the above material quickly.