In the paper, the current situation of higher solid fuel consumption for 2^# sintering machine in 2^# Sintering Workshop of Iron-making Plant of Baotou Steel is systematacially analyzed. The fuel with comprehensive particle size>5 mm is controlled at 15%~20% and that with comprehensive particle size<1 mm is controlled at about 30% through classifying different fuel bands, putting them into tank and crushing them as well as controlling reasonable proportion of anthracite and coke powder; effective material layer thickness is increased and automatic heat storage effect is improved through increasing height of baffle for trolley of sintering machine to 750 mm and reducing thickness of bed charge from 85 mm to 70 mm; overdamp layer of sintering is reduced through reducing moisture of sinter mixture from 7.2% to 6.9%. The solid fuel consumption in 2^# sintering workshop is reduced significantly through taking the above measures. It reached 50.33 kg/t in 2023, which is 2.13 kg/t lower than that in 2021, which lays the foundation for further reducing energy consumption in working procedure before iron-making.

When dry mechanical pump system is used to vacuumize for such vacuum refining systems as VD, VOD and RH, a large amount of dust generated in liquid steel will enter vacuum pipe with process gas. In order to protect vacuum pump, the precipitator needs to be installed in front of mechanical vacuum pump to remove dust in process gas. It is common to add a cyclone dust collector in front of bag filter so that occupied area is large as well as costs and operating costs are high. The precipitator introduced in this article is with the integrated structure of cyclone and bag. These two parts are installed in two compartments mode within one precipitator so that occupied area is small and costs are low. The integrated precipitator is with such characteristics as high dust removal efficiency, small pressure loss as well as convenient and rapid maintenance and repair through optimizing structural design so that long-term safe operations of dry mechanical vacuum pump are ensured.

The treatment of high-salt wastewater has always been a problem for production enterprises since its salt content is high as well as it is difficult to be treated and cannot be directly discharged into the environment. The harmless treatment of high-salt wastewater is achieved by combining such technologies as membrane treatment, ozonation and evaporation crystallization as well as the salt in water is concentrated into such crystalline salts as sodium chloride and sodium sulfate. As a result, the treated water is for recycling circuit.

There is often flocculent flow at nozzle during casting rare earth steel products with continuous casting machine so that the casting with normal casting speed could not be met. In severe case, the flocculation at tundish nozzle causes interruption of production so that continuous casting production is seriously affected. The steelmaking technologies of rare earth steel are optimized by studying the reaction mechanisms after adding rare earth elements into molten steel as well as analyzing the effects of oxygen content of molten steel, oxidizability of slag, protective casting of continuous casting machine and casting temperature on yield of rare earth Ce. As a result, the yield and castability of rare earth elements in molten steel are improved as well as the number of continuous casting heats for rare earth steel products reaches 25 so that scale production of rare earth steel products is ultimately achieved.

The locations of disqualification of flaw detection for defects are accurately positioned through manual flaw detection of Q355NE plates with disqualification of online flaw detection as well as the microstructure and defects of the locations of disqualification of flaw detection are analyzed with optical microscope and electron microscope. The results showed that the defect corresponding to disqualification of flaw detection for Q355NE wind power steel was the microcrack in the center of steel plate, microstructure of the microcrack area in the center was martensite and bainite with poorer plasticity, which was caused by segregation of C and Mn. At the same time, MnS inclusions with long strip shape as well as compound of titanium and niobium distributed in chain are found at the crack. The interfacial bonding energy of them and matrix is low, continuity of matrix is destroyed so that cracks are easily initiated with the effects of stress. The microcracks in the center are avoided and qualification rate of flaw detection for wind power steel is increased by improving the segregation during solidification process of casting blank and adopting the mode of offline slow cooling of steel plate.

In the paper, it is introduced a new type of wear resistant and low temperature resistant pearlitic rail with excellent performances is developed through designing material compositions and studying heat treatment process aiming at the operating environment of railway in alpine regions and performance requirements for service of rail. The test results showed that the improvement of impact energy of test steel at -40 ℃ was not obvious by adding 0.10% Ni on the basis of the chemical composition of 0.66%C-0.45%Si-1.10%Mn, but impact performance was more stable than that of test steel without Ni. After the heat treatment of test steel is started and temperature is increased to 780 ℃, the abnormal microstructure, martensite could be prevented to be generated as well as microstructure is pearlite and a small amount of ferrite and impact energy at -40 ℃ could reach 20.1 J.

In this paper, the combined process of low-nitrogen combustion+calcium-based desulfuration with fixed bed is proposed for flue gas treatment of heating furnace thorough comparing current common desulfurization technology with active carbon, SDS sodium-based desulfurization technology, calcium-based desulfurization technology with fixed bed and dry desulfurization technology with highly active calcium powder in metallurgical industry as well as selecting the desulfurization and denitrification technologies suitable for conventional walking beam reheating furnace of steel rolling mill by taking the ultra-low emission transformation for conventional walking beam reheating furnace of steel rolling mill as an example. After on-site implementation, the nitrogen oxides, sulfur dioxide and particulate matter in flue gas could all meet the ultra-low emission requirements so that the combined process could provide reference for enterprises in the same industry.

The dynamic CCT curve of low carbon high niobium steel is determined and drawn as well as the effects of cooling rate on microstructure are studied through static simulating rolling compression test of low carbon high niobium steel with MMS-200 thermomechanical simulator. The results showed that the microstructure was mainly composed of polygonal ferrite (PF), a little pearlite (P) and small quantity of acicular ferrite (AF) observed when cooling rate was 0.5 ℃/s; the microstructure was mainly composed of acicular ferrite (AF) and pearlite disappeared, but certain proportion of polygonal ferrite (PF) was still visible when cooling rate was 1.0 ℃/s; the transformation structure was completely granular bainite (GB) when cooling rate was increased to 2 ℃/s; the transformation structure was mainly composed of granular bainite (GB) and a small amount of ferrite bainite (FB) when cooling rate was increased to 5 ℃/s; the transformation structure was mainly composed of ferrite bainite (FB) and a small amount of martensite (M) when cooling rate was increased to 30 ℃/s.

The thermos mechanical control process (TMCP) has been difficult to apply in the field of seamless steel pipe. The control cooling equipment after rolling is developed combining with process flow of seamless steel pipe, the X52N seamless pipeline steel pipe is produced with on-line accelerated cooling after rolling through industrial practices as well as its physical and chemical properties and microstructure are studied. The practices showed that the costly alloy elements did not need to be added into the production with C-Mn steel, microstructure of material was regulated and controlled by on-line accelerated cooling after rolling so as to ensure mechanical properties of material to meet the standard requirements as well as follow-up offline heat treatment was not needed. As a result, the requirements of physical and chemical properties for long distance pipeline steel pipe X52N could be met so that low cost, short process and economic production are realized.

The longitudinal crack is the main defect of Q235B steel belt manufactured by CSP production line of CSP Plant. Such measures as restore the accuracy of associated equipment, reasonably use casting powder as well as improve temperature difference of water inlet and outlet for crystallizer are summarized through the correlation analysis of process control points causing longitudinal crack by analyzing the causes of longitudinal crack for hot rolled steel belt combining with the actual situation of CSP production line. As a result, the longitudinal crack defect rate of Q235B steel belt is effectively reduced and qualified rate of hot rolled steel belt is improved.