钢铁钒钛

DEVELOPMENT AND PROSPECTS OF VANADIUM BEARING LOW AND MICROALLOYED STEELS IN CHINA

CAO Yin-zhi, FU Jun-yan

2000, 21(3): 1-11.

Abstract(21) PDF(0)

Abstract:
The role of vanadium in low and microalloyed steels and the main products of vanadium microalloyed steels were introduced.The development of low and microalloyed steels in China was reviewed.The prospects for the development of vanadium microalloyed steels in China were described.

STUDY OF V—N MICROALLOYED STEEL FOR REINFORCING BARS

ZHANG Yong-quan, YANG Cai-fu, LIU Shu-ping

2000, 21(3): 12-15.

Abstract(19) PDF(0)

Abstract:
The effect of adding nitrogen enriched vanadium alloy (Nitrovan 12) into 20MnSi steel was investigated on the mechanical properties of the steel above.The results show under same vanadium content condition,the tensile strength and yield strength of Nitrovan 12 addded steel increase by 135 MPa and 117.5 MPa respectively compared to 80FeV added steel. Under the Same or similar Strength condition, the amount of Vanadium addition can be reduced by over 33.3% using Nitrovan 12 compared to 80FeV.By adding Nitrovan 12 alloy into the steel,the cheap nitrogen element can be fully used. The nitrogen promotes precipitation of V(C,N) in V-bearing steel and improves the effect of Vanadium precipitation strengthening.Based on the experiment results, the economical grade Ⅲ reinforcing bars was developed.

ROLE OF NITROGEN IN NON-QUENCHED AND TEMPERED STEEL

YANG Cai-fu, ZHANG Yong-quan

2000, 21(3): 16-22.

Abstract(20) PDF(0)

Abstract:
The beneficial roles of nitrogen in non-quenched and tempered steel were described.Among Nb,V,Ti,the solubility of vanadium is high in medium carbon steel.Therefore,vanadium is the most effective and common use strengthening element for non-quenched and tempered steel.Vanadium added into the steel plays two essential roles-grain refinement and precipitation strengthening by the fine carbo-nitrides precipitates. Compared with carbon,the affinity of vanadium to nitrogen is higher and the nitrides are more stable than carbides.Hence,nitrogen play an important role in controlling precipitation of vanadium carbonitrides in microalloyed steel.The experimental results show the increase in the nitrogen content in non-quenched and tempered steel changes vanadium interphase distribution,promotes precipitation of V(C,N),decreases the particle size of V(C,N) precipitates,hence,enhances precipitation strengthening effect of vanadium in the steel and improves strength of the steel by a big margin.Because nitrogen promotes precipitation of V(C,N),pins austenite-ferrite boundary effectively and refines the ferrite grain.The fine V(C,N) precipitates promote intragranular ferrite nucleation,furthe,refine ferrite.In non-quenched and tempered steel treated by microalloying element Ti,the increase in nitrogen content makes TiN particles more stable,retards the growth of austenite grain effectively.The full use of cheap and plentiful nitrogen can save expensive vanadium alloy,further decrease the production cost of non-quenched and tempered steel,provided a given strength level of the steel is ensured.Therefore,the nitrogen is a very cost-effective microalloying element in the steel.

APPLICATION OF VN12 ALLOY IN V-N MICROALLOYED STEEL

XIA Mao-sen, SUN Wei-hua, QIN Xiao-hai

2000, 21(3): 23-28.

Abstract(20) PDF(0)

Abstract:
The effect of vanadium-nitrogen combined microalloying on the mechanical properties of 20MnSiV and 16MnV microalloyed steels was investigated through the contrast tests of adding V-Fe（51.6%V） or nitrogen enriched vanadium alloy VN12（American priority product,80%V,12%N）,into 20MnSiV and 16MnV steels.Compared with VFe（51.6%V）,microalloying with nitrogen enriched vanadium alloy VN12 have good economical benefits due to vanadium saving.

APPLICATION OF VN ALLOY IN NON-QUENCHED AND TEMPERED STEEL

LU Xiang-yang, LIU Ming, JIA Bin, DONG Jun, DONG Cheng-rui, CUI Run-jiong

2000, 21(3): 29-33.

Abstract(22) PDF(0)

Abstract:
The application of VN in F35MnVN steel was introduced.The roles of vanadium and nitrogen and nitrogen adding process into molten steel were investigated.The results show in order to bring the role of vanadium into play,the nitrogen content in vanadium bearing non-quenched and tempered steel should be increased.The best nitrogen adding process is the use of VN alloy.

ANALYSIS OF SECONDARY PHASE PARTICLES IN Ti-V-Nb MICROALLOYED LINEPIPE STEEL

CHEN Mao-ai, TANG Yi-min, LOU Song-nian, WU Ren-jie

2000, 21(3): 34-38.

Abstract(24) PDF(0)

Abstract:
The secondary phase particles in Ti-V-Nb microalloyed linepipe steel were investigated using carbon extraction-replica technique.The results show there are a large number of fine dispersed particles in the steel.The larger particles like square contain higher Ti and lower Nb.The smaller particles of irregular shape contain lower Ti and higher Nb. The particles of more than 20nm size contain lower V. The electron diffraction analysis shows the particles have face-centered cubic structure. The dispersed particles retard the growth of austenite grains markedly.The austenite grains in the steel heated at below 1 150 ℃ grow at very low speed.The austenite grains in the steel heated at above 1 150 ℃ grow markedly.

ROLE OF RARE EARTH IN VANADIUM MICROALLOYED HOT ROLLED SHEET

TANG Li, WANG Yi-cheng, ZHAO An-yin, LIN Qin

2000, 21(3): 39-43.

Abstract(17) PDF(0)

Abstract:
According to contrast tests of adding rare earth or not adding rare earth into vanadium microalloyed hot rolled sheet steel,the results obtained show the rare earth treatment can clean molten steel,modify inclusions and is beneficial to improve the formability of the sheet. Also,the rare earth plays a certain part in microalloying and ageing-resistance of the sheet.

DEVELOPMENT OF HOT ROLLED SHEET FOR AUTO CHASIS FRAMES AT PANGANG

ZHANG Kai-jian, WANG Yi-cheng, SONG Li-qiu, YU Meng-wen

2000, 21(3): 44-48.

Abstract(17) PDF(0)

Abstract:
The hot rolled sheet used for auto chasis frames was developed by use of low C-Mn-V alloying,wire feeding,secondary steelmaking and controlled rolling techniques at Pangang.The over 20000 tons of the P510L,P440L,P420L and P370L hot rolled sheet have been produced,successfully used at autoworks. The mechanical properties of the sheet can meet user's demands.

ANALYSIS OF MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HOT DIP GALVANIZED SHEET PRODUCED AT PANGANG

ZHENG Zhi-wang, YU Li-ming, GUO Yong-an

2000, 21(3): 49-53.

Abstract(25) PDF(0)

Abstract:
The microstructure, texture and deep drawing property of hot dip galvanized sheet produced at Pangang were systematically analyzed. The measures to further improve the mechanical properties of the sheet were put forward.

FUNDAMENTAL STUDY OF NEW TREATMENT PROCESS FOR TITANIFEROUS BLAST FURNACE SLAG AT PANGANG USING PHASE SEPARATION

SUN Kang, WU Jian-hui, MA Yue-yu, HU Zhong-wu, WU Hao-bo, CHEN Hai-qun, YU Xiao-hua, QIN Wei-dong, LI Zhang-you

2000, 21(3): 54-58.

Abstract(18) PDF(0)

Abstract:
A new treatment process for titaniferous blast furnace slag at Pangang using phase separation was put forward. As the first part of the present work,the behavior of separation of molten substance from solid residues was examined.According to thermodynamical analysis and experimental determination,the main products of reaction between titaniferous slag and Na₂CO₃ at high temperature were complex silicon and titanium oxides containing sodium. Furthermore,under proper condition,it is possible to separate most of titanium and silicon from the rest in the slag.Under experimental condition,the particle size of the slag and temperature of the system influence the reactions markedly.However,the effect of the amount of Na₂CO₃ added is relatively weaker as long as the amount of Na₂CO₃ added is higher than that of stoichiometry.

STUDY OF DISCONTINUOUS LEACHING PROCESS FOR VANADIUM BEARING CLINKER

PENG Ming-fu, YANG Yang-jun, LIU Hui-qian, CHEN Zi-qing, WANG Xiao-jiang

2000, 21(3): 59-63.

Abstract(17) PDF(0)

Abstract:
The discontinuous roasted clinker leaching process for V₂O₃ production from converter vanadium bearing slag was introduced,The factors (temperature, time, number of times for leaching and washing)influencing leaching percentage were investigated. The results obtained from industrial production show the vanadium content in leaching solution can meet the requirement of the down stream process when the SV content in the residue after leaching and washing is decreased to <0 1%.

METALLIC IRON DISTRIBUTION IN V₂O₃ MATERIAL SYSTEM AND MEASURES TO REMOVE IRON

LI Si-zhong, PU Nian-wen, DENG Xiao-bo, ZHOU Zong-quan, LIAN Guo-qiang

2000, 21(3): 64-68.

Abstract(17) PDF(0)

Abstract:
The source of the metallic iron in V₂O₃ material system and the reasons for metallic iron concentration were analyzed.The factors influencing iron removal were discovered.The metallic iron content in beneficiated Vanadium bearing slag was decreased by means of the parameters equipment optimization and 3^# vibrating screen installed more.

STUDY OF RAISING TEMPERATURE OF MOLTEN STEEL IN CONVERTER WITH QUASI—GRAPHITE

WANG Jian, NIE Mei-ying, YANG Sen-xiang, PENG Tao, LIU Xin, WANG Sheng, XIE Hai

2000, 21(3): 69-72.

Abstract(14) PDF(0)

Abstract:
The raising temperature of molten steel in converter with quasi-graphite was investigated. The results obtained from 150 heats and expanded tests show the effect of raising temperature of molten steel with quasi-graphite is marked,the temperature compensation is 40.7℃ using 1 ton quasi-graphite.The use of quasi-graphite doesn’t influence slag formation and desulphurization and dephosphorization of molten steel during steelmaking process,can meet the requirements of steelmaking and slag splashing process.

2000 Vol. 21, No. 3