The very vigorous agitation at the interface on molten metal and slag in oxygen side-blown steel-making converters is a special feature which promotes the application of viscous slag operation.An investigation of end-point blow slags in the above-said converter has shown that many different types of viscous slags were corroded a little to the tarred dolomite lining bricks, and in certain cases the fused slags appear to stick and to creep upwards along the brick-lining forming a protection against erosion during operation. Thus, the application of viscous slag operation would appear to be prolonging the life of converter lining in steel-making.The nature of converter atmosphere at the time interval between the blowing periods and its interaction with slag have been investigated, as certain atmospheres are capable of reducing FeO in slag on thermodynamical considerations.In such case, it has been observed that when the total FeO of mean end-point blow slags was less than 12％, such slags in their usually fused condition to stick and to creep upwards along lining bricks. The slags crept upwards were chiefly composed of 3CaO·SiO_2 and 2CaO·SiO_2, with rather low 2CaO·Fe_2O_3 and other ferrous minerals content. It would appear that the "∑FeO" in the original endpoint blow slag of higher melting-temperature in its course of creeping upwards were progressively reduced by the converter atmosphere with the result of forming solid phases of higher melting-temperature such as 3CaO·SiO_2 and 2CaO·SiO_2.

The capacity of tolyl arsonic acids for collecting cassiterite has been investigated. It is shown that mixed tolyl arsonic acid was much superior to either para- or ortho-isomer alone for cassiterite flotation. Mixing ratios between paraand ortho-tolyl arsonic acids ranging from 50:50 to 30:70 were effective with a peak value at 45:55 in which a maximum collecting capacity was obtained. The preparation of mixed tolyl arsonic acid was more convenient than that of paraisomer, a conventional collecting agent for cassiterite flotation. In the plantscale flotation of cassiterite slimes assaying from 0.6 to 0.7 percent Sn, tin concentrates with the grade of about 25.65％ were obtained, the total recovery being about 58.64％. Cassiterite flotation using mixed tolyl arsonic acid as collectors and sodium carbonyl methyl cellulose as despressing agents for calcite have already been put into industrial practice.

Antimony white as a pigment is mainly judged by the degree of whiteness. With a view to improving the quality of the product, tests were carried out to investigate the effect of impurities contamination, the shape and size of the grains, and the crystal structure of antimony oxides. At the same time, methods of producing superfine antimony white on a large scale were also investigated. It was found that amongst the many factors the crystal structure of the grains was most important, thus the greater the amount of cubic antimony trioxide present, the better the quality of antimony white as revealed by its whiteness. Furthermore, long-time tests on a large scale showed that the best quality of antimony white powders could be obtained by suitable control of the primary and secondary oxidizing blast, the forced-air cooling flow, and the reaction chamber temperature.

The morphologies and distributions of MnS precipitates in grain oriented 3％ Si-Fe during the early stage of the secondary recrystallization have been examined by electron microscope. The lowest temperature at which the breakdown of primary grain boundary inhibition provided by MnS precipitates could occur was found to be about 1000℃ for common grain oriented 3％ Si-Fe. The necessary condition to obtain stabilized primary grain matrix was that the average size of original distribution field of MnS particles in the as-decarburized state approaches the Zener critical size of particles below which effective inhibition action occurs. It was found that the breakdown of MnS precipitates inhibition could not be related to the distribution characteristics of coarsenning particle field. The breakdown of the precipitates inhibition action upon primary grain boundary above 1000℃ might be ascribed to the complete dissolving of the precipitates below Zener critical size at this temperature.

The endurance of rare earth-magnesium nodular cast iron to fracture under static and dynamic loads is shown to be more accurately represented by the parameters of fracture mechanics rather than by impact toughness. Parameters such as K_(Ic), da/dN and AK_(th) are represented. With a view to clarifying the effect of various metallographic structures upon the fracture toughness of the material, the rate of spheroidization, the morphology of graphite, the size of spherulites, the matrix structure, etc. were separately examined. At the same time, crack propagation characteristics for different stages of fatigue fracture were also investigated. It is recommended that nodular cast iron could be in greater strength and better toughness provided that its microstructure is improved.

The Curie temperature of Y_2(Fe_(1-x)Ni_x)_(17) varied with its nickel contents (x) and a maximum T_c of 625 K, occurred at x=0.3. In order to investigate the effect of the replacement of Fe atoms by Ni atoms on the magnetic properties of such compounds, easy directions of magnetization were determined by X-rays for different Ni contents, and the dependence of the saturation magnetization in a magnetic field up to 70,000 Oe on x values of the compounds was also studied. Mossbauer spectra of Y_2Fe_(17) and Y_2 (Fe_(0.9)Ni_(0.1))_(17) were taken ~1to ascertain order or disorder distributions of Ni atoms in the crystalline lattices. An explanation of the cause of variation of Curie temperature with the Ni contents of the compounds has been given on the basis of the above results.

An investigation of the thermal stability of titanium alloy TA8 (Ti-5Al-2.5Sn-3Cu-1.5Zr) showed that the embrittlement was closely related to the surface structures of the alloy. The formation process of such surface structures has been discussed. On account of the fact that oxygen diffuses into the matrix of the alloy during thermal exposure, the precipitation of Ti_2Cu and α-ordered phase in high oxygen solid-soluted surface and/or near surface layers may play an important role in causing the embrittlement of the alloy.

A pulsed plasma-arc all-position welding technique has been successfully applied to the superheater and reheater tubing system jointing of power boilers on a large scale. The effect of processing conditions on welding puddle control and the coordination of the various main parameters from which the primary controlling parameter was chosen have been investigated. It was observed that gas pores caused either by incomplete penetration or by unstable molten puddle constituted the main weld defects, and certain remedy measures were found to be effective. The sound effect produced by the plasma jet impulse through key-hole has been considered useful in monitoring weld penetration and it may serve a signal for performance control of the above welding technique.

1. Carbides2. Nitrides3. Borides4. Silicides5. Sulphides6. γ′, γ″ and other Ni-Al compounds7. Topological close-packed phases8. Phase computation and alloy design of superalloysPhase computation (PHACOMP)Alloy computation (ALLCOMP)

Based on the concept of thermodynamical activity, carbon migration through the welding joint of dissimilar steels has been discussed. Apart from their difference in composition, their different crystal structures if exist may markedly influence the carbon migration and the effect of phase transformation must also be considered. The processes of the carbon migration may be classified as: 1. migration takes place quickly at high temperatures, the precipitation of preeutectold ferrite may given rise to violent migration; 2. migration takes place slowly at rather low temperatures, the diffusion rate of such elements as chromium which has a strong tendency to form carbide may be vital for carbon migration. Suggestion has been put forward on thermodynamic and kinetic considerations to retard carbon migration in either case cited above.