In this paper, it is comprehensively introduced the energy consumption is reduced by automatically controlling feed pressure based on the drum pressure by frequency converter and stand by pump is ensured to be put into automatic interlocking when the unit is started and in the condition of low load through optimizing control logics under the working condition of “one with two” for frequency converter of high pressure feed pump in the gas-steam combined cycle unit, which lay the foundation for stable operations of the unit.

The production rhythm of production line could be significantly improved and energy consumption per ton of steel of production line could be reduced by increasing hot charging and feeding rate of production line. In the paper, the characteristics of production line of hot charging and feeding for continuous casting billet of wide and thick plate of Baotou Steel are introduced. The hot charging and feeding rate of production line of wide and thick plate could be effectively increased through taking such measures as increasing the feedback speed of results for samples of compositions of molten steel in tundish and surface and internal qualities of plate blank as well as controlling hot charge cracks of steel plate.

With the continuous development of industry, the requirements of steel quality for various countries in the world are higher and higher. It has been current research emphasis how to improve the corrosion resistance of steel. The effects of rare earth elements on improving corrosion resistance of steel have been proved. In the paper, it is mainly elaborated the influence mechanisms of rare earth elements on modification of inclusions, causes of pitting, change of structure and components of rust layers as well as electrochemical corrosion resistance of low alloy steel through investigating a large number of literatures, which could provide the theoretical basis for promoting applications of rare earth elements in steel.

In the paper, the effects of adding dolomite, soft burnt dolomite and serpentine into infrared micro sintering furnace with different content levels of MgO on such properties as the fluidity of liquid phase and strength of bonding phase for iron ore powder are studied. The results showed that the sintering properties of adding soft burnt dolomite were superior to those of adding dolomite and serpentine, which mainly manifested in suitable fluidity index of liquid phase for iron ore powder within 0.6~1.2 at 1 280 ℃, the highest strength of bonding phase was 476.6 N and appropriate content of MgO was 2.0%. The sinter pot test results showed that the sinter added with soft burnt dolomite was with such advantages as high low temperature reduction degradation index, narrow drippage interval and small maximum pressure differences. The sintering of adding soft burnt dolomite is considered to be more beneficial to improving metallurgical properties of sinter based on the comprehensive comparisons of sintering properties of such three magnesium fluxes as the dolomite, soft burnt dolomite and serpentine.

As a type of very important soft magnetic material, non-oriented silicon steel is widely used in such electrical equipment as motor and transformer. In recent years, with the continuous development of science and technology, the requirements of energy conservation and emission reduction are increasing so that the requirements for performances of iron core material are higher. As an important alloying method, the addition of rare earth elements has significant effects on the properties of non-oriented silicon steel and has been widely concerned. In this paper, the effects of rare earth elements on inclusions, texture and magnetic property of non-oriented silicon steel are summarized as well as the future development direction is proposed according to present research status.

In this paper, the continuous cooling transformation (CCT) curve of X80 pipeline steel researched and developed in laboratory is determined. The determination results showed that the ideal microstructure of X80 pipeline steel could be obtained when cooling rate was 5~30 ℃/s, which was granular bainite + ferrite bainite + a small quantity of martensite/austenite island; the microstructure transformation was basically completed when finish cooling temperature was 450 ℃. The determination of CCT curve could provide references for subsequent optimization of composition design, establishment of process parameters and control of microstructure.

During the process of manufacturing automobile rims by purchased 420CL steel of one wheel plant in the winter, there is welding deformation cracking at edge of the rims with remained “rolled round edge” of steel coils. The metallographic structure and microhardness of edges with and without cracking of rim are detected with metalloscope and microhardness tester respectively as well as the causes of cracking are analyzed. The values of microhardness of weld seam, coarse grain heat affected zone, fine grain heat affected zone and parent metal at edge of the rims with remained “rolled round edge” of steel coils are 217, 215, 223 and 150 respectively, while those without “rolled round edge” of steel coils are 222, 230, 235 and 220 respectively. The difference of microhardness for welding heat affected zone and parent metal at edge of the rim with cracking is about 70, this is the main cause for cracking of rim. After flash butt welding, the difference of material hardness for welding fine grain heat affected zone and without welding heat effect along edge of rim is too large so that the deformation coordination ability at edge of rim is destroyed and the stress concentration is generated at juncture to cause cracking.

In this paper, the effects of replacing iron ore concentrate of Inner Mongolia Autonomous Region with finely ground super special powder on production process and properties of pellet are systematically investigated based on the configuration of raw materials of producing acid pellet with the process of traveling grate-rotary kiln-rotating annular cooler of Baotou Steel. Meanwhile, the maximum proportion of Barun concentrate in producing pellet is explored based on the characteristics of low sulfur for finely ground super special powder. The results showed that the proportion of bentonite could be reduced obviously by adding the finely ground super special powder into pellet of Baotou Steel. When the proportion of finely ground super special powder is 10%, proportion of bentonite could be reduced from 2.0% to 1.2%, which is a significant reduction. When the proportion of finely ground super special powder is 5%~20%, performance indexes of green pellets and dry pellets could all meet production requirements of pellets. Under the condition of calcination temperature of 1 220~1 240 ℃, the compressive strengths of finished product, oxidized pellets prepared with different proportions of finely ground super special powder all reach over 2 500 N and reduction swelling rate is lower than 20%, which could meet the requirements of blast furnace production. It is suggested to produce pellets with the configuration of iron charge of 10% finely ground super special powder+50%~60% Barun concentrate+30%~40% iron ore concentrate of Inner Mongolia Autonomous Region for the process of traveling grate-rotary kiln-rotating annular cooler considering the grade of pellets and content of Al₂O₃. Under the raw material condition of 10% finely ground super special powder and 1.2% bentonite, the maximum proportion of Barun concentrate could reach 60%.

With the environmental protection and production limitation, the output of sinter is becoming increasingly tense after 1^# and 2^# sintering machines in 1^# sintering workshop are not in the production sequence as well as the addition of large proportion of pellets into blast furnace has become new development trend of iron-making. During this test, 5^# blast furnace is with trouble free operations through regulating charge level, adjusting central coke quantity and discharging sequence of feed zone, optimizing parameters of tuyere and area of inlet air, increasing heat reserve of hearth, adjusting and controlling basicity of slags as well as actively coping with various changes of furnace conditions after increase the proportion of pellets. The smelting production is successfully realized in the 1 500 m³ blast furnace of Baotou Steel with structure of furnace charge of large proportion of pellets and use ratio of pellets reaches 52%, so the fuel ratio is stable with a slight decline.

The frequent quality defect of corner crack for casting blank of carbon structural steel with conventional composition design of medium carbon and low manganese seriously affects the hot charge rate of products. With the original equipment and working conditions, composition optimization design is carried out. The mechanical properties of products are ensured through replacing part of C with microalloying element Ti as well as replacing solution strengthening with fine-grain strengthening and precipitation strengthening. Meanwhile, the high temperature plasticity and corner crack of casting blank are improved through liquation of second phase particle for TiN with the high temperature of Ti microalloying to fix free nitrogen atom in liquid steel. The rate of corner crack for carbon structural steel Q235B with new composition design is controlled effectively through the evaluations of mass production and applications.