钢铁钒钛

BEHAVIOR OF CGHAZ TOUGHNESS AND PRECIPITATES OF UNDERWATER WELDED Ti-V-Nb MICROALLOYED PIPELINE STEELS

Shi Yonghua, Wang Guorong

1999, 20(4): 1-6.

Abstract(21) PDF(1)

Abstract:
Microstructure, impact toughness and precipitation behaviors of Ti-V-Nb particles in both the underwater and in-air welded coarse-grained heat-affected zone(CGHAZ) of X60, X65 and X70 microalloyed pipeline steels were investigated.The precipitate composition was also examined with Energy Disparsive X-ray(EDX) unit.The results showed that grain size of high-Ti steels (X60 and X70) CGHAZ zone was smaller than that of low Ti steels(X65) and impact toughness higher than that of it.It is related to the stability of different microalloying precipitates(Ti-rich and V-rich) in the thermal weld cycles and their different size distributions in parent materials.Higher cooling speed of underwater wet welding resulted in the presence of greater quantity martensite in the CGHAZ so that their impact toughness was lower than that of in-air welding.

LADLE SLAG TREATMENT TECHNIQUE AND OPTIMIZATION OF BOTTOM ARGON BLOWING PARAMETERS

Li Yangzhou, Wang Mingdong, Li Zhongchao, Gu Wuan, Yan Xuemo

1999, 20(4): 7-12,17.

Abstract(20) PDF(1)

Abstract:
As refining slag is fed into ladle, Σ(FeO +MnO) ≤ 2.64% in the ladle slag is achieved and slag basicity is increased by 1.21 on an average.When parameters of ladle bottom argon blowing is controlled to 8~12 Nm³/h flow rate and argon blowing time is over 5min, T[O]in molten steel will be decreased by 25.88% on an average.

DEVELOPMENT OF CASTING POWDER FOR PREVENTION OF NITROGEN PICKUP DURING TUNDISH PLASMA HEATING

Yao Qiuyang, Fan Guangqian, Tong Fusheng, Zhao Hui

1999, 20(4): 13-17.

Abstract(17) PDF(1)

Abstract:
The casting powder for prevention of nitrogen pickup during heating is developed in accordance with the issue of nitrogen pickup during continuous casting tundish plasma heating. The effect of composition and technological parameter on properties of the casting powder is also studied and the proper composition ranges of casting powder are identified, which is significance to the application of plasma heating rechnology of continuous cast tundish.

STUDY OF HOT GUNNING MATERIALS FOR CONTINUOUS CASTING TUNDISH

Wang Huaibin, Zhang Jidong, Ao Jinqing, Fan Fuzhong, Xiao Mingfu, Zhang Junxiang, Zhao Qicheng, Li Maolin

1999, 20(4): 18-23.

Abstract(15) PDF(1)

Abstract:
A study of hot gunning materials for continuous casting tundish is introduced and physical and chemical property indexes of hot spraying coating materials are obtained. The hot spraying materials developed are characterized by high hot gunning adhesion without crack and spallation during drying and baking and inclusion adsorption and molten steel cleaning and have the advantages of long service life and easy demolition etc. The use of hot spraying materials developed is also discussed.

DEVELOPMENT AND OPTIMIZATION OF CONVERTER V-RECOVERING PROCESS AT PANGANG

Ge Wensun, Yang Subo, Wang Jian, Zhang Dade, Zhang Yudong, Lin Maoqiang, Xu Hua, Ji Kebin, Chen Yong

1999, 20(4): 24-29.

Abstract(24) PDF(2)

Abstract:
In accordance with the characteristics of low vanadium bearing hot metal and the present situation of converter V-recovering process, the technical indexes of converter V-recovering process, i. e. V-recovery rate of 80.9% and V-oxidizing rate 90.4% as well as semi-steel yield rate 93.94% are largely improved through the systematic development and optimization of converter V-recovering process at Pangang. The oxidizing characteristic of key elements during vanadium recovering in converter is also studied in this paper.

A STUDY OF PRE-REDUCED PELLET MELTING RATE

Dong Lingyan, Qiu Guibao, Zhang Binghuai

1999, 20(4): 30-34.

Abstract(21) PDF(1)

Abstract:
The effect of hot metal bath temperature, pellet basicity and pellet pre-reducibility on melting rates of the pre-reduced ore and the pre-reduced vanadic titanomagnetite pellet is studied. Apparent activation energy of the pellet melting is calculated and the equation of the melting rate of pellet under the condition of laboratory is established.

A TEST OF TITANIA SEPARATION FROM HIGH TITANIA BEARING BLAST FURNACE SLAG

Zhou Zhiming, Zhang Binghuai, Zhu Zizong

1999, 20(4): 35-38.

Abstract(36) PDF(1)

Abstract:
Alkaline separation agents are added into high titania bearing blast furnace slag. Structure of perovskite in the slag is destroyed at the high temperature and co-molten slag formed is leached in water. The tests indicate that the interaction of slag and separation agents belongs in the acid一base reaction at optimum temperature ranges of 1 200~1 300℃ and TiO₂ content in the slag is reduced to a certain degree after leaching.

A STUDY OF COMPOSITE HIGH-SPEED STEEL ROLL RING WITH CENTRIFUGAL CASTING

Wu Weiqiang, Fu Hanguang

1999, 20(4): 39-42,49.

Abstract(24) PDF(1)

Abstract:
Composite high-speed steel roll ring is studied using centrifugal casting process. The results indicate that the high speed composite roll rings with high hardness, good homogeneity of hardness and excellent inner and outer joint can be obtained by choosing modified high-carbon cobalt-free high speed steel as outer layer and nodular cast iron as inner layer, suitable centrifugal rotating speed and casting span time and temperature of both metal liquids in combination with surface induction heat treatment process. The service life of the roll ring is five times larger than that of high chromium cast iron roll ring in application to industry.

DEVELOPMENT AND APPLICATION OF CONTINUOUS CAST COMPOSITE ROLL WITH BUILD-UP WELDING AT PANGANG

Li Dadong, Lin Jiandong, Sun Jingming, Xu Zichao, Li Zaiyou, Liu Weizhong, Yao Chengbao, Qiu Daorong

1999, 20(4): 43-49.

Abstract(31) PDF(1)

Abstract:
Continuous cast rolls are welded in build-up through the single-wire submerged arc welding technology used commonly at home. The properties between 15CrMo roll ore matrix and build-up welding metal are compared through the tests and the process parameters of build-up welding are chosen and optimized, in which properties of continuous cast roll with build-up welding reaches to enterprise technique standard. The test on industry application indicate that the service life of build-up welded continuous cast composite rolls is 3-6 times larger than ordinary 15CrMo build-up welded continuous cast rolls.

KINETICS OF SUPERFINE α-FeOOH PREPARED WITH AIR OXIDATION PROCESS IN TRACE ALKALI MEDIUM

Hu Hongfei, Zhu Shengyou, Jiang Zhigang, Zheng Lin

1999, 20(4): 50-54,66.

Abstract(12) PDF(1)

Abstract:
Reaction kinetics of superfine α-FeOOH prepared with air oxidation process in trace alkali medium is studied. The effect of primary sub-ferrous ion concentraction (C₀), reaction temperature (T), stirring rate (n), partial pressure of oxygen (po₂) and alkali/ferrous ratio (R) on reaction rate is analyzed and equation of reaction kinetics during nuclear forming period has been established with zero stage reaction for both Fe(Ⅱ) and partial pressure of oxygen and apparent activation energy of reaction is 12.25 kJ/mol.

A TEST OF CLASSIFYING CRUDE ORE WITH NEWINCLINED-BLOCK CLASSIFICATION BOX AT PANZHIHUAIL MENITE PROCESSING PLANT

Liu Yao, Lan Guangming

1999, 20(4): 55-58,66.

Abstract(14) PDF(2)

Abstract:
The tests of classifying titanium-containing ore with new inclined-block classification box in laboratory and on an expanded scale are carried out. The indexes of subsequent expansion test in 72 hours period are 35.9% underflow concentration and 93.99%-63μm grade mineral in overflow and 76.50% recovery.

AN EVALUATION FOR THERMAL SCHEDULE OF REHEATING FURNACE AT PANGANG RAIL-BEAM ROLLING PLANT

Chen Yong, Pei Youcai, Zhao Wen, Sun Hao, Han Shuguang

1999, 20(4): 59-61.

Abstract(25) PDF(1)

Abstract:
Heating curves of billet for heavy rail in reheating furnace are measured by use of dragging coupling methods. Effects of fuel consumption, furnace temperature and heating time on billet temperature are studied and current thermal schedule of reheating furnace is evaluated, which provides the basis for optimizing and improving thermal schedule of reheating furnace.

DETERMINATION OF TOTAL CARBON IN V₂O₃ WITH INFRARED ABSORPTION CARBON-SULPHUR ANALYSIS UNIT AND INFLUENCING FACTORS

Xu Benping, Yi Guihua, Miao Yuyan, Niu Maojiang, Zhong Hua

1999, 20(4): 62-66.

Abstract(16) PDF(1)

Abstract:
An analytical method of measuring carbon in V₂O₃ with infrared absorption carbon-sulphur analysis unit(CS-344) is established through a number of comparative tests, work curve correction and standard addition process. The method and carbon analysis data are reliable through rechecking. Determination results show that relative standard deviation ≤ 7.0% is achieved by accuracy test within the range of 0.02%~0.05% C in V₂O₃. Through a number of tests it is identified that Ammonium salt present and carbon content in V₂O₃ decreased gradually with longer time are major influencing factors on accurate measurement carbon with the infrared method.

1999 Vol. 20, No. 4