Abstract: This paper presents a systematic thermodynamic calculation about the behavior of potassium,sodium and their chemical compounds in the blast furnace. Based on sample analysis from experimental blast furnace of Bao-Tao st.Co and material balance of wensi blast furance of shan-xi procvince in Smelting potassium orthocluse rocks and the data of sinchan provincical steel Co in smalting Yamansu ore,the formation conditions of potassium and sodiam compounds in the blast fornace cre associateal.
Abstract: The inflnence of Iron (0-25%) on the microstructure and properties of a cast Nickel-Base superalloy is examined The results of this study show, that the gamma prime fraction in alloy and gamma prime size decrease with the Iron addition in alloy. The morphology of gamma prime is changed from cube to spheroid and the amount of MC is increased, but both amount of M23C8 and M3B2 are reduced as Iron coutent iucreases. The partition ratio of alloying elements between γ-γ' is changed and average electron-vacancy number $\bar N$v is increased apparently by Iron addition in alloy, thus the precipitation of sigma phase is accelerated. The amount of harmful elements is increased with Iron addision in alloy. Iron addition in alloy severely decreases the stress repture, but slightly iufluences the tensile strength of this cast nickelbase superalloy. Simultaneously, the ductility of alloy with high Iron content is low.
Abstract: The three dimensional flow of metals during rolling of ingot with liquid core has been studied in the article. Here the influence of liquid core ratio on rolling was studied in particular. Tests have shown that ingot with lipuid core ratio up to 6% could normallλ be rolled. Fuel consumption of rolling of in got with liquid Core was reduced by 80% compared with that of normal rolling productivity of soaking-pit furnace was increased by 30%。 Achievements in this scientific research have been applied to blooming Production.
Abstract: GY-1 mill stand is a new type of housingless mill based on the des ign principle of short stress path and fewer mating surface. The roll unit is not prestressed but the stand is very stiff and gives excellent dimensional accuracy The main features are high reliability, low maint enance and simple service. A symmetrical roll gap adjustment gives a fixed pass line which means easy adjustment and go.od economy he accuracy of the presetting is so high that test pieces are not neccesary after a new dimension changes. Experience has shown that the roll stand can replace the old under-capacity mill and gives satistactory resultsThis paper chiefly deals mith the mechanical principle and mecha nism of this roll unit.
Abstract: A special but representative sort of Team Problem involving binary logical variables has been studied in this Paper The so called Weighted Boolean Polynomial Expression(WBPE), which links real variable space with logical variable space, was proposed as a short approach to the solution of this sort of Team problem. After having discussed many important properties of WBPE, such as Completeness,Orthogonality,Generation and Degenration, the author developed a concept of General Payoff Matrix, or W-matrix, and demon strated its skill through a typical example given by prof.Y.C.Ho [5].
Abstract: The kinetics of rare-earth effect on low carbon steel containing arsenic has been studied in this paper. By means of kineticin-ves tigations, the behaviour of arsenic in this steel wasexamia-ed. Our experiments confirmed that rare-earth addition can suppress the concentration of arsenic on tne surface of tne steel during tne hot pressingo.
Abstract: The equilibrium of reaction FeCl2+$\frac{1}{2}$Cl2$ \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} $FeCl3 in the melt has been studied. It has been shown that FeCl3 decomposes almost fully at Pc12→O, and that Fe(Ⅲ)/Fe(Ⅱ)=1.36 at PC12=latm and t=700℃. The higher the temperature, the smaller the ratio Fe(Ⅲ)/Fe(Ⅱ). The electrode kinetics of iron species in the melt has been studied by cyclic voltammetry. It has been found that the cathodic reaction Fe (Ⅱ) +2e→Fe(0) is controlled by diffusion of Fe(Ⅱ) in the melt, and that the apparent activity energy of the cathodic reaction is 12.9±4 KJ/mol, and the diffusion coefficient of Fe(Ⅰ)is (4.31 ±0.79) ×10-5cm2/s. Anodic reaction Fe(Ⅱ) -e→Fe(Ⅲ)is also controlled by diffusion and followed by a rapid chemical reaction Fe(Ⅲ) +Cl-→Fe(Ⅱ) + $\frac{1}{2}$l2. So, the current efficiency for removing iron by electrolysis should not be effected considerably by the changes of oxidation states of iron species between cathodic and anodic compartment. The above results have been shown to be correct by electrolysis in Lab. scale. Co-deposition of mag-nsium is the main reason of low current efficiency for removing iron by electrolysis. Current efficiency can increase to 70% under following conditions:700℃ cathodic c. d. 0.2A/cm2 and PC12→0 in the cathodic compartment.
Abstract: The activity of Nb in molten iron was studied at three temperatures, 1823, 1853 anp 1873K with the solid electrolyte oxygen cell technique, the following cell assembly being adopted: Mo, Ho + ZrO2 Cermet|Mo.MoOt||ZrO2 (MgO)||(Nb), NbO2|Mo To equilibrate the (O) Content of the Nb-containing iron, Pure Solid NbO2 particles were scattered over the surface of the melt under Purified argon atmosphere, and in some cases, the surface of the melt was left bare under the purified argon atmosphere, the oxide, which was ascertained thermodynamically as NbO2, being formed by itself as the deoxidation product. By elaboration with the experimental data of a0 determined, the following results were achieved: 1. The free energy of the reaction of deoxidation: [Nb]+2[O]=NbO2(S); ΔG°=-89710 + 28.27T 2. The free energy of sulution of Nb in iron: Nb(s)=(Nb)%; ΔG°=-32090 + 7.9T;γ$\mathop 1\limits^{\rm{^\circ }} $873=1.60 Nb(l)=(Nb)%l ΔG°=-38520 + 10. 24T,γ$\mathop 1\limits^{\rm{^\circ }} $873=0.92 3. The self activity interaction coefficent of Nb: ${\rm{e}}_{{\rm{Nb}}}^{{\rm{Nb}}}=\frac{{2274}}{{\rm{T}}}-1.44$ When the (Nb) content in the iron was less than about 0.2%, similar to the behavoir of other alloying elements such as Al. Cr, V etc, a complex oxide, probably FeO · NbO2, was formed. The free energy of this complex oxide from its elements was estimated to be: Fe(1)+$\frac{3}{2}$O2+Nb(s)=FeO·NbO2(s);△G°=-383800+121.95T The possibility Of the presence of other deoxidation products, as the (Nb) content in the molten Iron was decreased still further, was also discussed.
Abstract: Sulfur and sulfur dioxide are important species in many high temperature systems. The ability to continuously monitor sulfur and sulfur dioxide concentrations in coalgasification environments and exhaust gases is essential for controlling corrosion and air pollution problems. In this work. four necessary conditions are summarized for develop a successful design of an electrochemical sensor. According to these condition a new sensor using a two-phase electrolyte (alpha-Li2 SO4 and (Li5Ag)2SO4 solid solutions) and a Ag/(Ag2S04) reference electrode has been developed. This sensor can measure sulfur dioxide and/or sulfur trioxide concentrations over a wide composition range in oxidizing atmosphere. The potentiometric response is stable and reproducible for long term measurements.
Abstract: This paper describes in detail the relationship between the resoluttion, signal to noise ratio and the experimental data from EXAFS measurement.It has been presented the opinion of critical condition for experimental data and the method of a precise measurement. The relationship between resolution, singnal to noise ratio and the critical experimental data have been discussed and the following conclutions have been introduced at the critial condition: 1. The resolution is independent on the rocking curve width of the monochromator crystal when the width of entrance slit and exit slit both equal to the critial data but the signal to noise ratio depends on which is more important to the mosaic structure size that is characte-rized by the rocking curve wicth of the mono-chromactor crystal:the intensity distribution or the extinction effect. 2. The entrance slit width increases to the optimum that the resolution keepsa constant and the signal to noise ratio increase obviously wh the width of exit slit and the rocking curve of monochromator crystal equal to the critical data. But the signal to noise ratio does not in crease with the entrance slit width if the width is largerth an the op timura. It has been shown in the paper that the conclution 1 is more suitable to that where the perfection of the monochromator crystal is not good enoughi and the conclution 2 is fit to perfect crystal.
Abstract: Stress corrosion cracking (SCC) of austenitic stainless steel in a boiling 42% MgCl2 solution under compressive stress was investigated. Specimens with surface residual compressive stress, U-bend specimens and notched compressive specimens of modified WOL type were used. The results showed that SCC under compressive stress occurred for these three type specimens after 110, 73-100 and 262-324 hours respectively. Fracture surfaces of SCC under compressive stress were quasi-cleavage characterized by stratified rock structure and striation-like pattern rather than river marks or fan pattern under tensile stress. The incubation period of SCC under the compressive stress is much longer and the propagation rate of the crack is much slower than that under the tensile stress. Therefore, SCC under the compressive stress usually can not occur if there exists simultaneously the tensile stress in a apecimen or structure. The possible role of hydrogen in SCC of this system is discussed.
Abstract: In the hydrogen resistant steel alloy carbides are formed to fix carbon so as to avoid the formation of methane at Fe3C, that causes hydrogen damage.This Process depends not only on an appropriate design of the steel composition, but also on aproper selection of heat treatment This research was doneby using complex phase analysis method to study the precipitation of alloy carbides and their relationship with hydrogen in 12SiMoVNb steel. By normanizatibn at lOOO℃ and tempering at 720-740tJ small carbides (most one of them is V4C3) distribute in the ferrite matrix and solid solution strengthening by Mo% V, Nb were obtained. They are both decisive factors in achieveing good arc mechanical properties and promoting the resistance against hydrogen attack at 400t and at PH2-200 kg/cm2.
Abstract: The X-ray diffraction patterns of amorphous alloy Fe80B20 before and after cold rolling deformation have been compared. The first peak of the diffraction pattern shift slightly to a smaller angle and the width of the peak slightly increases after cold rolling.The increase of the width of this peak should be the due result of the increase of the short-range disorder of this alloy. A computer program of determination of the RDF of amorphous material was worked out by the authors and the RDF curves of amorphous alloy Fe80B20 before and after cold rolling were determined.Within the precision allowed in our experiment no change of RDF of this allloy before and after cold rolling has been observed.
Abstract: On the condition of plane strain it is assumed that the workpiece is a rigid-plastic material with strain hardening, the roller is a rigid-body,the frictional condition of the contact surface between the roller and the workpiece is no slip i.e. no relative slide between them.We have used the rigid-plastic finite element method to calculate the pressure per unite area,the velocity of metal flow and the stress-strain distribution,etc; and suggested New view on determining the Length of deformed arc, the rigid-plastic boundaries, the coefficient of front slide and the neutral angle. The computer programme of the finite element method is based on the general rigid-plastic variational principles. The 8-nodal curved quadrilateral isoparametric element is introduced. The results of the calculation have been compared with the experimental data of aluminium plate rolled on the 4-high mill.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
