钢铁钒钛

RESEARCH ON STRENGTH AND TOUGHNESS OF ULTRA-FINE GRAIN STEEL

SONG Li-qiu, ZUO Jun, SHE Guang-fu, LIU Yong, LIU Jian-hua

2004, 25(2): 1-5.

Abstract(42) PDF(0)

Abstract:
The strength and toughness of hot rolled strip with ultra-fine grain produced in industrial process were analyzed.The results show that the microstructure of hot rolled strip with ultra-fine grain is ferrite and pearlite.The ferrite grain size is about 3~5 μm.The tensile strength is over 510 MPa, and the yield strength is over 400 MPa.The hot rolled strip with ultra-fine grain is of high strength, high elongation and superior toughness.

STUDY ON AGING RESISTANCE OF RUTILE NANO-TITANIUM DIOXIDE IN POLYPROPYLENE PLASTICS

CAO Jian-jun, GUO Gang, WANG Bin-hua, DUAN Xiao-ping, WU Jian-chun, HUANG Wan-xia, TU Ming-jing

2004, 25(2): 6-12.

Abstract(51) PDF(0)

Abstract:
The polypropylene is filled and modified with rutile nano-titanium dioxide as anti-aging additives. The property and feature of rutile nano-titanium dioxide are gained by a series of indicating methods, such as TEM, XRD, UV-VIS and so on. Polypropylene is degradated by accelerated aging test with xenon arc lamp. The variation law for mechanical properties of polypropylene is studied during the weathering test in contrast. The fracture morphology of polypropylene and the disperse state of rutile nano-titanium dioxide are analyzed by SEM. It is noted that rutile nano-titanium dioxide and its composites can upgrade the toughness and strength of polypropylene, improve the weatherproof property of polypropylene, and prolong the service life of polypropylene.

STUDY ON MELTING TEMPERATURE AND VISCOSITY OF Al₂O₃-CaO BASE PRE-MOLTEN REFINING SLAG

ZHAO He-ming, WANG Xin-hua, XIE Bing

2004, 25(2): 13-18,26.

Abstract(83) PDF(1)

Abstract:
The melting temperature and viscosity of Al₂O₃-CaO base pre-molten refining slag containing SrO was studied by means of quadratic orthogonally regression. A mathematical model having high significance was founded. The effects of single factor and two factors on the physical properties of refining slag were discussed. The optimal value of each composition is respectively 8%SiO₂,7%MgO,6%SrO,5%CaF₂,Al₂O₃/CaO=0.8, and this result is a theoretical support for further study.

CONTROLLED ROLLING TEST FOR HIGH STRENGTH AND DUCTILITY H-BEAM IN RECRYSTALLIZED ZONE

FENG Jian-hui, ZHANG Liang-ming, LI Tong

2004, 25(2): 19-22.

Abstract(42) PDF(0)

Abstract:
Applying the controlled rolling and controlled cooling theory of steel,the authors took simulation rolling of microalloyed H-beam in austenite recrystallized zone using Gleeb-2000,and analyzed the metallographic structure of experimental samples.The affect of heat temperature and rolling pass reduction on final organization and grain size was discussed.Based on the results of simulation test,the reasonable controlled rolling process is worked out for developing high strength and ductility H-beam product.

EFFECT OF AUSTENITE DEFORMATION ON CONTINUOUS COOLING TRANSFORMATION

YU Chi-bin, YAN Fei, ZHAO Gang, CHEN Liang, SU Yi, HU Min

2004, 25(2): 23-26.

Abstract(45) PDF(0)

Abstract:
Applying a THERMECMASTOR-Z hot simulator,the austenite deformation on high temperature and the characteristics of transformarion with continuous cooling were studied for a low carbon Mn-Nb-T microalloyed steel.The dynamic CCT diagram of the steel is established under the deformation conditions.The results indicate that the recrystallization temperature of the steel is 950~980 ℃.The increase of cumulative deformation under recrystallization temperature causes the transformation temperature rising at same cooling rate after the deformation.The recrysallization temperature decreases along with the cooling rate increase.

STUDY ON EROSION PROCESS OF VANADIUM-TITANIUM BEARING SLAG WITH HIGH ALKALI CONTENT ON BLAST FURANCE LINING

XU Guo-tao, DIAO Ri-sheng, DU He-gui, SUN Xi-wen

2004, 25(2): 27-34.

Abstract(43) PDF(1)

Abstract:
The variation of refractory materials’ structure and composition after eroded by vanadium-titanium bearing slag with high alkali content was analyzed on the basis of laboratory erosion experiments. The results show that alumina-carbon brick is of outstanding alkaline attack resistance, the attacking rate of clay brick and alumina brick is increased when the vanadium-titanium bearing slag contain alkali, the alkaline attack resistance of corundum-mullite brick is poor. Densifying the structure of refractory material which is attacked easily by alkali and is of high reactivity is a improvement goal for further research.

DEVELOPMENT OF MOLD POWDER FOR 09CuPRE SERIES STEEL

CHEN Tian-ming

2004, 25(2): 35-39,48.

Abstract(39) PDF(0)

Abstract:
Based on analyzing the main problems of ordinary mold powder used in casting of 09CuPRE series RE-treated steels at PZH Steel and the research upon effect of RE oxide(RE_xO_y) on the properties of mold powder,a prefused mold powder with low solidification temperatures and low crystallization temperature and strong ability of absorption and solution of RE_xO_y was developed. This mold powder is of suitable component,special fluxes and inferior oxidizability. Industrial experiment results show that the developed mold powder is satisfied with the demand of 09CuPRE series steels casting process, the ratio without slab surface finishing is >95%, no one breakout accident happened in the past 3 years.

APPLICATION OF VN ALLOY IN PRODUCTION OF LARGE SIZE ANGLE STEEL

FENG Yun-li, LIU Zhan-ying, CHEN Chun-sheng, WANG Yun-ge

2004, 25(2): 40-43.

Abstract(38) PDF(0)

Abstract:
Large size angle steel is mainly used in fabricating transmission tower. Tang Gang used 16Mn to produce Q345 grade angle steel. Owing to the narrow composition range, the production of Q345 grade angle steel is difficult. A new steel 16MnV(N) was designed by using V-Fe and VN alloy, which has better mechanical properties. The analysis in properties of 16Mn, 16MnV, 16MnV(N)angle steels shows that VN is a suitable alloy as microalloying large size and high strength angle steel.

RESEARCH ON DOT GRAPHITE ALLOY CAST IRON MATERIALS FOR MOULDS

DENG You-fu

2004, 25(2): 44-48.

Abstract(45) PDF(0)

Abstract:
The function of alloy elements in dot graphite alloy cast iron is presented, and the effect of alloy elements on heat analysis curve of dot graphite alloy cast iron is discussed. The steady-quality molds of dot graphite alloy cast iron was produced by adjusting the chemical compositions, controlling the crystal temperature range of new austenite and the eutectic reaction temperature. The rigidity of mold is evenly and meets the user's demand.

OPTIMAL AIR TO WATER RATIO IN MISTING COOLING PROCESS

MEI Guo-hui, WU Rong-yang, MENG Hong-ji, CI Ying, XIE Zhi

2004, 25(2): 49-51,70.

Abstract(75) PDF(1)

Abstract:
cooling efficiency in the continuous casting. Usually it could be got from experiments or the experience,but it would take high cost,long period and hard difficulty. In this paper,the factors for controlling intensity were analyzed. The relevant equation between cooling intensity and water rate of flow,impacting velocity,droplet size was built. And the cooling intensity was calculated by the equation. The results show that there is a optimal air to water ratio,yet it is variable and decease with water pressure increase. It is very significant to reduce the energy consumption of second cooling in continuous casting.

EFFECT OF INCUBATION PROCESS ON LOW TEMPERATURE COMBUSTION SYNTHESIS OF Fe-Ti-C SYSTEM WITH ELECTRIC FIELD

FENG Ke-qin, YANG Yi, LIN Hui-min, SHEN Bao-luo, HE Hong

2004, 25(2): 52-56,70.

Abstract(38) PDF(0)

Abstract:
Using Gleeble-1500D, the effect of incubation process on the low temperature combustion synthesis process of Fe-Ti-C system under several technological conditions was studied. The results show that the ignition temperature of Fe-Ti-C system can be decreased greatly under the action of electric field and great thermal density, and the ignition temperature is 390~570 ℃ under different technological conditions. Moreover, the process of incubation 2 minutes at 200 ℃ has a great influence on the low temperature combustion synthesis of the system, both the ignition temperature and the highest temperature of the compact with incubation at 200 ℃ are higher than that of the compact without incubation. And the results of X-ray diffraction for synthesized products show that the products of the compact with incubation at 200 ℃ consist of TiC and Fe, however, the products of the compact without incubation consist of TiC , Fe and a little Fe₂Ti.

RESEARCH ON FORMING REASONS AND PREVENTION MEASURES OF LONGITUDINAL SURFACE CRACKS ON CSP THIN SLAB

HONG Bing-xiong, MAO Xin-ping, CHAI Yi-zhong, ZHU Bo-ping

2004, 25(2): 57-61.

Abstract(68) PDF(1)

Abstract:
The longitudinal surface crack on thin slab is a serious quality defect at CSP line. Through analyzing the forming reasons, it is found that controlling the scrap quality, liquid steel composition, overheating degree in mould, powder quality, recycling water quality in the mould,keeping good condition of mould and segment,and the installing precision of submerged nozzle are effective to prevent the forming of longitudinal surface crack.Besides,maintain good match relationship between casting temperature and castiong speed is also effective to prevent the forming of longitudinal crack.After adopting the above measures,the rate of forming longitudinal crack is reduced to less than 0.4% stably at Zhujiang Steel.

EFFECT OF [S] ON STRENGTH AND IMPACT TOUGHNESS OF HIGH PURIFICATION LOW ALLOY STEEL PLATE

ZHAO Zeng-wu, WANG Xin-hua, CHANG Guo-wei

2004, 25(2): 62-65.

Abstract(72) PDF(1)

Abstract:
The effect of [S] on the strength and toughness of low alloy steel plate in which sum of [P], [N], T[O] is less than 80×10^-6was investigated. It is found that the strength of the steel plate decreases with [S] increasing when it is less than 50×10^-6. And when [S] is more than 50×10^-6, the variation of [S] has no significant effect on the strength of steel plate. The ductile-brittle transition temperature drops and its difference between length direction and width direction reduces with decreasing [S] content of steel plate. However, even when [S] is reduced to 10×10^-6, the difference of ductile-brittle transition temperature is still 16 ℃.

TEST AND ANALYSIS ON SURFACE ROUGHNESS AND MICRO-PROFILE OF COLD-ROLLED STEEL SHEET

TANG Jing

2004, 25(2): 66-70.

Abstract(42) PDF(1)

Abstract:
There are three kinds of cold-rolled steel sheet with different surface, as they were rolled by three types of cold-rolls whose surface were textured respectively by shot blasting, electro-discharge and laser. Using GBS-60 cupping test press to stamp the above-mentioned steel sheets, and the surface roughness and micro-profile of sheets before and after stamping were surveyed by SEM. Make a comparison between the surface roughness and micro-profile before and after deformation show that SEM image are in good accordance with measured roughness, and the distribution of roughness can be observed directly. The plastic deformation of the sheets can be analyzed by SEM images.

2004 Vol. 25, No. 2