The aluminum is often used as the deoxidizer in production process of slab. In the theoretical thermodynamic calculation, the amount of aluminum deoxidizer could keep dynamic equilibrium of aluminum and oxygen in liquid steel within limits. If beyond the limit, the surplus aluminum forms non-metallic inclusions so that the cleanness of molten steel is deteriorated and the performances of steel are affected. In the paper, it is analyzed and studied the changes of amount and size for inclusions with different amounts of deoxidizer in converter through industrial tests by taking the L415M steel as an example, elaborated the effects of reducing the amount of deoxidizer on inclusions in the whole production process of high grade pipeline steel. The ratio of inclusions (Class B) less than grade 2 in rolled products is increased from 96.8% to 99.83% by proposing the optimization scheme for controlling the cleanness of molten steel.

In this paper, the effect laws of adding a certain proportion of high silicon Brazilian coarse powder ore into sintering on its technical indicators and quality of sinter with current raw material conditions of Baotou Steel are studied. The experiment showed that the complementary ore proportioning could be realized by adding a certain proportion of high silicon Brazilian coarse powder ore taking the ore proportioning structure that the self-produced iron ore concentrate by Baotou Steel adding Australian limonite and semi limonite as the main framework, which was conducive to improving the quality of sinter. The industrial experiment showed that the rate of sintering finished products, drum strength of sinter and size composition were improved after add the high silicon Brazilian coarse powder ore into sintering of Baotou Steel.

The basic pellet with limestone and low reduction expansion rate added 75% Bayan Obo iron concentrate is researched and developed aiming at the special nature of Bayan Obo iron concentrate. It is suggested that the proportion of bentonite is 1.5%~1.8%, alkalinity is 1.15±0.05 and proportion of limestone is 3.5%~3.8% for producing basic pellet with the process of chain grate machine-rotary kiln-ring cooler of Baotou Steel as well as explored the basic pellet is with such process system as good compressive strength, mineral composition and metallurgical properties, which could provide the technical supports for producing it with chain grate machine-rotary kiln-ring cooler of Baotou Steel.

In this paper, the influences of super-thick material layer on sintering process indexes as well as productivity and quality of sinter based on the iron material configuration condition that high proportion of iron concentrate of sintering of Baotou Steel are mainly elaborated. The study results showed that the FeO content of sinter could be significantly reduced by increasing thickness of sintering material layer, the thickness of material layer was increased from 700 mm to 1 000 mm and the FeO content of sinter was decreased by 1.39 percentage points, or 14.2%. The solid fuel consumption of sintering could be effectively reduced, yield and drum strength of sinter could be improved by increasing the thickness of sintering material layer. In this paper, such indexes as the fuel consumption, yield, drum strength, RI and RDI_{+3.15 mm} of sinter tend to be increased then decreased with the thickness of material layer increases as well as they are optimal when the thickness of material layer is 800 mm, which shows that the suitable thickness of material layer is 800 mm with the iron material configuration condition of 20% Barun iron concentrate+20% Mongolian iron concentrate+60% imported iron ore powder.

There are such problems as the temperature at gas inlet of burner for Kalugin top combustion stove is too high, package is red as well as weld joint of gas pipeline cracks and leaks. After soldering and surface air cooling, the effects are not obvious. It is found that the internal refractory bricks collapse through opening pore on the pipeline. Thus, the special measures are taken as well as the area is sprayed and with lining making to repair so that the hot air temperature returns to normal, blast temperature of blast furnace keeps at 1 200 ℃ for normal production and the effects are obvious.

The liquid steel could be purified, inclusions could be modified and steel could be microalloyed by adding rare earth into steel, which could reduce the harmful effects of inclusions on steel so that the plasticity, toughness and resistance to low temperature impact of steel could be improved. In order to study the effects of different rare earth contents on properties of steel, the smelting of low alloy high strength steel with manganese and different quantities of rare earth added and without rare earth are carried out using the 25 kg vacuum medium frequency induction furnace as well as the rolling with production process on site is simulated. Moreover, the chemical composition, mechanical properties, fracture and metallographic structure of rolled products are analyzed. The results showed that the grain size of microstructure for steel could be refined by adding rare earth into steel; with the increase of rare earth content in steel, refined grain size of microstructure makes the resistance to crack formation and propagation between grain boundaries increased so that the plasticity, impact toughness and mechanical properties of steel are improved.

In the paper, it is found that the hardness and wear resistance of working layer for cast iron roll are improved as well as the labor costs are reduced by developing continuous rolling concave roll with the metal spraying process through optimizing such key control points as the chemical composition and production process of continuous rolling roll as well as comparing and analyzing its mechanical properties and microstructure before and after optimization, which provide the technical basis for developing large grooved roll and roll collar in future.

Based on the investigation of technical requirements and production process for like products of pressure vessel steel, the chemical composition design, rolling and research of normalizing process for Q370R are carried out as well as the effects of normalizing temperature on the microstructure and properties of test steel are studied. After normalizing, the strength of steel plate added microalloying elements Nb, V and Ti is decreased, elongation and impact energy are increased significantly. With the increase of normalizing temperature, strength of test steel is decreased gradually. The strengths of steel plate with rolled state and the same normalizing process added a small amount of Cr are both higher than those of the steel plate without Cr, while the elongation and impact energy are lower than those of the steel plate without Cr. The cost of per ton of steel will be increased by adding a small amount of Cr. After normalizing, the microstructure is fine grained ferrite and pearlite. Based on the comprehensive consideration, test steel with the composition system of adding microalloying elements Nb, V and Ti as well as the properties of steel plate with controlled rolling and normalizing at 840~880 ℃ could meet the standard requirements.

The accuracy of performance characterization for material has crucial influences on the numerical simulation results. In the software CAE, it generally contains the material cards of European mainstream material suppliers and a small number of domestic manufacturers, but due to different material characteristics of each manufacturer, the corresponding material card of material with the same grade shows different data distribution law as well as the criterion of yield and hardening. Thus, it is an indispensable link in such product applications as evaluation of stamping process as well as design and manufacture of mould to accurately characterize the characteristics of their own products and establish own material cards for material manufacturers. In the paper, the test scheme suitable for presenting cold stamping performance is established and data processing method is studied by taking the typical grade DC04 for cold stamping steel as the objective. Finally, the material data card for stamping simulation analysis which could accurately characterize product characteristics of Baotou Steel is developed. After adjust the working condition of stamping based on the calculation guidance of material data card, the stamping process suitable for performance characteristics of sheet matal of Baotou Steel is obtained to ensure the accuracy of simulation technology support and accurately improve the applicability of product.

The process parameters of hot rolling and controlled rolling, pickling-rolling and continuous annealing for steel strip are determined through the composition system design based on the technical requirements of continuous annealing steel strip HG400 for slide rail. The mechanical properties of the product produced with industrial production line could meet technical requirements and its elongation after fracture is 21%~26%. The study on optimizing the production process of continuous annealing is carried out aiming at the problem that elongation after fracture is lower as well as continuous annealing temperature and elongation of temper mill are adjusted. After the optimization, elongation after fracture of product could be stably controlled at about 31%. At present, the product is produced stably and applied widely.