1436. Degassing ShKh15 ball bearing steel

1436. Degassing ShKh15 ball bearing steel

Classified abstracts 1429-1441 types appear to be the property of clean platinum substrates. two types of structures are discussed in some detail. ...

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Classified

abstracts

1429-1441

types appear to be the property of clean platinum substrates. two types of structures are discussed in some detail. H B Lyon and G A Somerjai, 2.539-2550.

J Chem Phys, 46 (7), 1st April

The 1967,

37 1429. The effect of vacuum outgassing time on the fatigue behaviour of two structural aluminium alloys. (USA)

Testing was performed on 2024-T351 and 7075-T6 Al alloys at a constant maximum stress. Specimens were tested in air, vacuum with short (20 hr) outgassing time, and vacuum with long (160 hr) outgassing time. For the 202&T351 alloy, lifetime increases of 4.7 and 15.1 times the air fatigue life were observed for the short and long outgassing times, respectively. Increases of 4.1 and 13.6 times the air value were observed for the 7075-T6 alloy. The results indicate that the fatigue lifetime increases as the outgassing time, prior to fatigue testing, is increased. D W Hoeppner and W S Hyler, Mater 599-601.

Res Standards,

1430. Investigation on the casting properties alloyed austenitic steels and alloys. (USSR)

of

6, Dee 1966, 37 vacuum-melted,

The effect of melting and teeming in vacuum on casting properties of complex alloys was investigated, emphasizing austenitic steel and nickelbase alloy. It was found that the duration of crystals under vacuum was 20-60 per cent longer than under atmospheric conditions. An increase in fluidity of the steel and alloy was noted in the vacuum process. The gas content was also determined. No change was found in linear shrinkage, but a reduction in volumetric shrinkage was observed. G F Stasyuk, Steel casting and foundry work in the USSR, English tramI, Rep JPRS-38574; TT-6634999, 1966 (Joint Publication Research

Service,

Washington,

DC). 37

1435. Influence of process technology on the production castings from high temperature casting alloys in vacuum.

37 of precision

(Germany) The influence of process variables on the surface quality of precision vacuum castings of nickel and cobalt alloys were investigated with particular reference to the effects of metallurgical factors on the incidence of surface defects. P Rack, Freiberger Forschungsh, No B124, 1966, 155-213 (in German). 37 1436. Degassing

ShKblS ball bearing steel.

(USSR) Trials include degassing in the ladle, ladle-to-ladle degassing and a combination of degassing with synthetic slag treatment. The vacuum equipment is described. Vacuum treatment of deoxidised ball hearing steel in the ladle did not reduce hydrogen content or nonmetallic inclusions. Ladle-to-ladle degassing reduced the hydrogen content but resulted in unfavourable amounts of non-metallic inclusions. Synthetic slag treatment reduced the oxide rating and the hydrogen content of the steel and combined with vacuum treatment reduced the oxide rating and the hydrogen content of the steel and combined with vacuum treatment reduced the susceptibility to hydrogen flaking without adversely affecting the steel quality with regard to non-metallic inclusions. G A Schmatko et al, Metallurg, No 2, 1967, 12-14 (in Russiam). 1437. Effect of the method of degassing steel. (Poland)

on the hydrogen

37 content of

The predominant factor in degassing steel is the attainment of a very high degree of vacuum. The process is also improved by teeming the metal during degassing, which ensures hydrogen removal from the whole of the bulk metal and not only from the surface layers. Additions of deoxidizers tend to promote hydrogen removal. Z Kliseiwicz,

Hutnik,

33 (9), 1966, 357-361

(in Polish).

1431. Vapour phase growth of ruby monocrystals.

(USA) The technique of preparing large, high perfection ruby monocrystals by vapour phase growth was further investigated and developed. A device was incorporated into the system which increased control of total pressure during crystal growth. Ruby crystals were successfully grown using chromium chloride and chromium carbonyl as sources of chromium vapour. Positioning the ruby crystal such that the longitudinal axis was perpendicular rather than parallel to the impinging reactant gas stream, was investigated. Oxidation potential was determined to be an important process variable affecting Cr,O, concentration. La.ser oscillation of a vapour-grown ruby compared to Verneuil and Czochralski grown rubies showed it to be of high optical perfection. P S Schaffer, Rep A D-638007, Aug 1966 (Lexington L,abs, Inc, Cambridge,

Massachusetts).

1432. Mass-spectrometric pressure in the NaF-AIF,

investigation of the composition system. (USSR)

37 and vapour

The NaF-AlF, system was analysed using the MU-1305 massspectrometer with the particular attention to determination of the partial pressures of Na,AlF, and (NaAIF,), both of which are sources of the Na2AIF,+ ion. L N Sidorov et al, Dokl Akad Nauk SSSR, 37&373 (in Russian).

173 (2), I I th March

1967,

37 1433. The influence of vacuum teeming on some physico-mechanical properties of structural steel. (USSR) Some properties of 12KhN3A steel, teemed in air and under vacuum (l-2 torr) are compared. The vacuum treatment was found to reduce, to some extent, the amount of dissolved gases and non-metallic inclusions in the steel. While no influence on the static strength was observed. the vacuum treatment improved the low temperature ductility bf the stsel. Y A Starovoitov et al. Fiz Khim Mekhan Material. ..,2 (6). 1966.637-640 (in Russian).



37 1434. Fatigue fracture of vacuum melted ball bearing steel.

(USA) Mechanical, metallographic and electron microfractographic studies were carried out to obtain fundamental data on the initiation and propagation process of fatigue cracks on the fatigue fracture surfaces of vacuum melted ball hearing quality steel, SUJ2. T Yokohari 1529-I 542. 490

and M Nanbu, Proc

1st Intern

Conf Fracture,

3, 1966,

1438. Reaction kinetics of concentration changes occurring surface of vacuum annealed alloy steels. (Czechoslovakia)

37 at the

The application of reaction kinetics to the determination of the depletion of the surface of alloying elements is considered. The kinetic constants of Cr and Mn were calculated from measurements on IO different alloy steels and the results compared with data from the literature. Good agreement with experiment was found and it is concluded that the kinetic theory may be employed to predict variations in alloy concentration occurring at the surface during vacuum annealing. K Stransky,

Kovove

Materialy,

4 (4), 1966, 309-320

(in Czech). 37

1439. Furnaces and vacuum heat treatments.

: IO

(France)

Units of pressure measurement and the various methods of production of low pressures are described as well as the measurement of vacuum by mechanical, liquid or thermal-ionization pressure gauges: The technology of construction of vacuum and hot wall furnaces is outlined. G Tardy, Traitement Therm, No 25, Jan-Feb 1967, 3 l-39 (in French). 37 1440. Development and operational experience with the refractory lining of a DH degassing plant under the special conditions of combination with a continuous casting plant. (Germany) The life of the refractory lining in the degassing vessel was extended by employing magnesite bricks and modifying the shape of the bottom of the vessel. However it was found that the slag on the top

of the melt had a very great effect on the life of the refractory lining and by using special fluxes together with particular care of the bottom lining the life could be extended to 500 heats. K Bick et al, Klepzig

Fachber, 75, Jan 1967, 43-47 (in German). 37

1441. Vacuum treatment of liquid steel in the ladle.

(Sweden) The deoxidation reaction of carbon in vacuum treated steel melts was investigated with particular regard to the conditions for evolution of carbon monoxide which ensures homogeneous composition of the steel melt. The effect of the slag layer was found to be beneficial under vacuum provided that the slag did not contain too high a proportion of easily reducible oxides. It was concluded that the application of vacuum treatment allows the production of killed low-carbon steel, deoxidized only by carbon with the additional possibility of pouring the steel into a continuous casting machine. A M Samarin, Jernkont

Ann, 151 (2), 1967, 113-125 (in English).