In order to remove the calcium and magnesium ions in ammonium sulfate wastewater, ensure subsequent trouble-free operations of water treatment process, improve quality of ammonium sulfate solid and recover magnesium resource, the calcium and magnesium ions in ammonium sulfate wastewater are removed with solvent extraction method in experiment. The P₂₀₄ and kerosene are used as extractant as well as pH value of ammonium sulfate wastewater and saponification degree of P₂₀₄ are adjusted so that the step-by-step removal of calcium and magnesium ions in ammonium sulfate wastewater is realized. The data support for industrial applications of this method is provided by such experimental conditions as determining pH values of the solution and comparing.

The industrial production process of rare earth steel involves the problem of yield of rare earth and stable yield is the important guarantee for stable performances of rare earth steel products. The effects of addition of position, addition amount and composition of liquid steel (oxygen activity, sulfur content) on yield of rare earth for rare earth steel are studied by adding rare earth in ladle and sampling analysis of tundish. The results showed that the yield of rare earth was increased in turn by adding rare earth in ladle, tundish and crystallizer; the larger the addition amount of rare earth alloy before off-position of ladle furnace, the lower the yield; the higher the contents of oxygen and sulfur in liquid steel, the lower the yield of rare earth.

Such effective measures as adopting optimum parameters of power transmission, forming refining white slag with microfoam as early as possible, optimizing modes of bottom blowing, accurate temperature control as well as optimizing dust removal control and electrode wrench are taken through experiments of multiple heats aiming at such phenomena as oxidation, melting loss, thermal vibration and drop out of electrode easily occurred during the heating process of ladle furnace. As a result, the consumption of electrode for ladle furnace is decreased from 0.544 kg/t in 2021 to current 0.347 kg/t so that stable and trouble-free operations of smelting for ladle furnace is ensured as well as cost decreasing and benefit increasing and high efficiency continuous casting are achieved.

The targeted optimization and improvement measures are proposed by summarizing and analyzing the existing quality problems of ER70S-6 welding wire steel. The emphasis is strictly controlling such key indicators as chemical composition range, gaseous nitrogen content, dimensional accuracy and microstructure of ER70S-6 welding wire steel. After tackling the problems, rates of reaching the standard for internal control of C, Si, Mn, and N contents are improved, class C accuracy of dimensional deviation is improved as well as abnormal duplex grain structure is eliminated. The drawing results of users showed that the quality of optimized welding wire steel were further improved, which could meet the requirements of high speed drawing with drawing speed of over 28 m/s.

In this paper, it is systematically introduced the characteristics of impurity distribution for slurry pipeline and effects of pigging with different types of tube cleaner by taking the pigging and descaling for a long distance high pressure slurry pipeline of iron ore concentrate with variable diameters as an example. It is found through actual pigging that the passability of pipeline could be preliminarily detected with soft foam pig and mechanical tube cleaner with leather cups of different shore hardnesses. In addition, the effect of cleaning scale for slurry pipeline with foam pig is poorer, so the mechanical tube cleaner with stronger pigging ability should be preferred, which is with important guiding significance for pigging of similar slurry pipelines in the future.

The stamping simulation workstation for sheet products of Baotou Steel is the typical research platform of applied technologies. With the coordinated supports of “numerical simulation and finite element simulation” technologies, it relies on multiple high performance personal computers to complete massively parallel computation so that the joint interactions of such four main fields as “stamping simulation analysis” “construction of material database” “correlational research of surface” and “comprehensive simulation” are realized. A large amount of simulation analysis is carried out on the platform, which not only provides the basis for optimizing and adjusting the processes and performances of sheet products, but also contributes to winning market reputations for high-end products such as automotive sheet of Baotou Steel. At the same time, the construction of material database promotes the substantial progress of early vendor involvement (EVI).

In the process of producing HRB500E rebar for domestic manufacturers, there are often low strength-to-yield ratio or a small amount of nonconformity. In this paper, the comparative experiment of niobium vanadium composite rebar and vanadium nitrogen rebar manufactured with industrial trial production is carried out. The results showed that the strength-to-yield ratio of rebar was increased by 0.03 with the niobium vanadium composite process, ferrite transformation was delayed due to presence of niobium, pearlite content was increased by about 10 percentage points so that tensile strength was increased; vanadium nitrogen alloy was relatively reduced due to the addition of niobium so that its precipitation strengthening and fine grain strengthening effects were reduced as well as yield strength of rebar was slightly decreased. The practices show that the strength-to-yield ratio of rebar and seismic resistance of HRB500E rebar are significantly improved with the niobium vanadium composite process.

The IF (Interstitial Free) steel plate is welded into steel pipe for manufacturing condenser pipe of household appliances by a user. There are local spot defects on the surface of steel pipe when it is subjected to conventional hydrostatic test. Such tests on chemical compositions, microstructure of defect and non-metallic inclusions of spot defects as well as mechanical properties and metallographic microstructure of the steel plate with base metal are carried out with such means as metalloscope and scanning electron microscope. The results showed that there were abnormal microstructures at the spot defects. The abnormal microstructures contain such alloying elements as Cr and Ni, which are different from the chemical compositions of matrix. When foreign matter is pressed into welded pipe, its local stress is concentrated. During hydrostatic test, the leak points of pressuring are at the foreign matter which is weakly combined with matrix. In order to avoid such surface defects, it is necessary to strengthen quality monitoring during the whole production and processing processes of welded pipe to prevent foreign matters from pressing into matrix to destroy its continuity so that the steel quality is reduced.

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.

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.