At the initial stage of producing cold rolled low carbon steel SPCC with the continuous annealing cold rolling production line of Baotou Steel, there were the problems that the yield strength was higher and the yield platform. In the paper, the effect of dislocation pinning is achieved through reducing the content of [N] in the chemical components of SPCC aiming at the above problems. In view of the differences between continuous annealing and cover annealing, the performance optimization for cold rolled steel SPCC with continuous annealing is finally realized through increasing the hot rolling coiling temperature of strip steel from 650 ℃ to 710 ℃ and controlling the precipitated phases of carbides and nitrides for strip steel after hot rolling to reduce the yield strength and eliminate yield platform.

In the paper, the basic reasons for the qualified rate for negative deviation of screw-thread steel are determined and the control level of basic reasons is established by taking φ25 mm screw-thread steel as an example, combining with the idea of six sigma using DMAIC steps to solve problems and supporting by data. As a result, the qualified rate for negative deviation of screw-thread steel is increased from 65.6% to 91.36% in order to better adapt to the delivery of screw-thread steel by theoretical weight, increase product profit and reduce costs of per ton of steel.

There was obvious center porosity in the production of Q345B round continuous casting billet, so the gas content and hot acid of continuous casting billet were tested as well as the solidification process of continuous casting billet was analyzed. The results indicated that the lower strength of mold electromagnetic stirring and final electromagnetic stirring caused fewer nuclear of grain, the lower strength of secondary cooling caused the full growth of grains, the grains piled up at the end of liquid core and divided the molten steel, the volume of molten steel in enclosed cavity was shrinked in the solidification process and formed small contraction cavity. The relative improvement measures are put forward based on this.

In the paper, the characteristics and production of H08A wire rod for arc welding are introduced. The requirements for chemical composition of steel grade are achieved by studying the control for low carbon and low silicon content of H08A steel for welding electrode, especially controlling the low silicon content; the trouble-free operations of continuous casting process is realized through studying the pourability, especially controlling the Ca/Al ratio; the billet quality is accepted through control study for the defect of rimhole of billet, especially controlling the oxygen content; the ideal microstructure of pearlite and ferrite is obtained through studying controlled cooling process of rolling. Finally, the batch industrial trial production of H08A is realized and all indicators could meet the requirements of users.

The effects of layer thickness of wind turbine blade with composite material on performance of blade are obvious and the effects of fibre cloth with different angles on structure property of blade are different since it occupies different layer thickness. The characteristics and law on effects of layer thickness of unidirectional fiber fabric on the performance of fan blade are investigated by taking the genetic algorithm as the optimization algorithm and taking a 1.5 MW mature fan blade as the research model. According to the structural features of wind turbine blade, the appropriate modeling method is determined as well as the objective function, genetic operators (selection, crossing and variation) suitable for the asymmetric laminate are found out. On this basis, the optimal solution of the layer thickness for fan blade laid with different fiber cloth is obtained.

The production practices show that the 12Cr1MoVG steel tube with medium thick wall is easily to be with lower tensile strength, low impact toughness value, uneven even unqualified impact value after the treatment of "normalizing + tempering", the tensile strength could be over the upper limit due to the influence of cooling speed after normalizing if with the treatment of complete "quenching + tempering". In the paper, it is introduced the overall performances of 12Cr1MoVG steel tube are excellent by adopting the method of intermittent" quenching + tempering" with the existing quenching equipment of Baotou Steel.

In the paper, it is introduced the content of silicon carbide in warming agent was determined with the combustion gas volumetric method by burning the sample at about 800 ℃ to remove the free carbon, dissolving carbonate with acid, filtration and washing. The determination conditions such as the temperatures of starting decomposition and complete decomposition for silicon carbide, preheating time and selection of sample weights are discussed as well as the optimum working conditions are found out. The measurement range of content of silicon carbide with this method was 1.00%~45.00%. 11 times of determination were carried out with 4 types of warming agent samples and the relative standard deviation (RSD) were 0.952%, 0.446%, 0.590% and 0.490% respectively. Compared with other methods, the results were the same.

The thermal performance is an important index for coal injection production technology of large blast furnace. In order to quickly and accurately analyze the reactivity and post-reaction strength of coke, the effects of cold charge and hot charge of coke sample on analyzing speed were studied. The comparison results of experiment showed that there were not great differences between the thermal performance analysis result of charging sample after the furnace body was cooling from 1 100 ℃ for 2 hours and that of charging sample when the furnace body temperature was at room temperature, which could meet the requirements of quickly analyzing sample and guiding the production on site.

In the paper, the technological process of modified pitch is introduced. The forms and causes of damages for reaction kettle are summarized through tracking the maintenance and operation of reaction kettle for many years. Moreover, the damages of reaction kettle are retarded and its service life is prolonged through transforming and strengthening the operations so that the accidents are avoided, equipment maintenance costs are reduced and composite economic results are improved.

In order to reduce the energy consumption and production costs of enterprise, the energy saving technology of speed control device with wrapping connector driving of permanent magnet eddy is applied on the dust-removing fan for steel rolling. As a result, the speed control of dust-removing fan can be realized with the condition of meeting the requirements of production technology so that the dust-removing fan is operated efficiently and a lot of electric energy is saved.