In the article, it is introduced the rail is deformed violently in rolling process and internal compactness is changed greatly due to the cross section size of ingot blank increases when rolling 60 kg/m rail using ingot blank with the cross section of 320 mm×415 mm instead of that with the cross section of 280 mm×380 mm in the production of rail. In order to ensure the product quality in rolling process, the roller of each rolling mill is adjusted to ensure stable as rolled state. After rolling the finished products, the macrostructure, microstructure, grain size and impact performance of rail are tested and analyzed with such equipment as the optical microscope, scanning electron microscope and impact testing apparatus. The results showed that the compression ratio of ingot blank was increased by rolling rail with large size ingot blank so that such mechanical properties as grain size and impact of rail could be improved.

In this paper, the industrial experiments of different heat treatment processes for X65Q seamless steel tube with medium thick wall are carried out as well as its microstructure and properties are tested and analyzed. The test results showed that the martensite content of X65Q seamless steel tube with specification of Ф406.4 mm×26.19 mm was gradually reduced from inner wall to center after quench with 3 300 m³/h inner and outer spraying as well as the microstructure of its internal surface was tempered sorbite+bainite, microstructure of its outer surface was bainite; after quenching, its grain size reached grade 8.5, transverse impact value at 0 ℃ reached over 200 J and yield strength reached over 500 MPa with tempering of 630 ℃ so that the strength and toughness of material matched well, which could meet the requirements of API 5L standard.

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.

Tower crane is the mechanical equipment playing a leading role in the construction of high rise buildings as well as it is widely used because it could achieve any work height and work range through installing and attaching. Its installation and disassembly are more dangerous projects, so construction organizations should pay high attention to the safety technology management of installing and disassembling tower crane. In the paper, it is introduced the construction process of demolition with tower crane, mainly discussed the problems need to be solved in the process as well as elaborated the construction preparation, order of demolition with tower crane, safety precautions and reinforcement measures of truck crane at different positions of roof for underground garage in detail, which could be as the reference for construction of demolition with tower crane.

In the process of rolling wire rods with Φ5.5 mm and Φ6.5 mm in Long Products Plant, the accident of piling-up of steel is easily to happen at the water cooling section after finishing rolling so that the rhythm of production and output are affected. Its true causes are found out through analyzing its phenomena, morphology and microstructure of its samples with the scanning electron microscope so that the probability of repetitive accidents and its times of piling-up of steel at water cooling section after finishing rolling are reduced. After the rectify and reform, the ratio of piling-up of steel is reduced to 0.013%, cumulative failure time is reduced to 35.8 hours and rejection rate is reduced to 0.027%.

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.

In this paper, it is introduced the CCT curve of 700 MPa grade high strength steel is measured with the Formastor-F full automatic phase change instrument and its microstructures at various cooling rates of 0.5~118 ℃/s are analyzed. The results showed that the transformation product was ferrite and pearlite when the cooling rate of test steel was 0.5 ℃/s; bainite structure began to form when the cooling rate was more than 1 ℃/s; bainite structure began to increase and perlite structure began to reduce with the cooling rate gradually increased; pearlite structure disappeared as well as the structure was ferrite and bainite when the cooling rate was 10 ℃/s; transformation products were mainly bainite when the cooling rate increased to 118 ℃/s. The analysis on the CCT curve and microstructure of 700 MPa grade high strength steel provide the theoretical basis for formulating heat treatment technology in actual production processes.

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.

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.

Such elements that could refine grain as V, Nb, Ti, Al and rare earth (RE) are added into the medium carbon steel as well as the stable compound formed by N, C and elements that could refine grain is used to refine the austenite grain and increase the strength and toughness of non-quenched and tempered steel. The stable compound formed by N, C, V, Nb, Ti and Al are observed with metallographic microscope and transmission electron microscope so that the non-quenched and tempered ferrite-pearlite steel is successfully developed. Its yield strength is greater than 550 MPa, tensile strength is greater than 780 MPa, hardness (HB) is not less than 210, elongation is greater than 18%, reduction of area is greater than 45% and impact value of V-notch at room temperature is greater than 50 J. Compared with common non-quenched and tempered steel, the non-quenched and tempered steel F28MnSiVTiRE is with such advantages as high strength and toughness and free cutting so that it could be used for machining such components as vehicle crankshaft and engine connecting rod.