The small-diameter boiler tube is designed and developed through innovating process design as well as its quality indexes are improved by Inner Mongolia Baotou Steel Special Steel Pipe Co., Ltd. based on the requirements of group company, “break through and improve product quality”. The seamless steel pipe with outer diameter of 51~114.3 mm and wall thickness of 3.5~12 mm is rolled by continuous casting billet of Φ150 mm in the original design of the unit. The demand of small-diameter boiler tube with outer diameter of 38~48 mm and wall thickness of 3.5~8 mm in the boiler tube industry is greater. The seamless steel pipes of two groups of outer diameter produced with the billets of the same diameter is realized and their wall thickness accuracy is -7.14%~9.14% through researching and developing the technology of large tube reducing rate for continuous mill unit as well as producing the seamless steel pipe with outer diameter of 38~48 mm by continuous casting billet of Φ150 mm. When rolling small-diameter boiler tubes made of materials of 25MnG, 15CrMoG and 12Cr1MoVG, there are defects of “straight fold” on inner surface as well as “linear indentation” and “subsurface cracks” on outer surface of steel tube. Their causes are analyzed combining with the deformation process and material characteristics as well as the solutions are formulated so that qualified rate of ultrasonic flaw detection of product is increased from 86.82% to 91.32%. The heat-treatment schedule for small-diameter boiler tubes made of materials of 15CrMoG and 12Cr1MoVG is formulated as well as the mechanical properties of products are stable under this process schedule, which could meet the requirements of GB/T 5310-2017 standard.

In this paper, it is briefly introduced the research and development and production processes of rare earth rails, summarized researches of rare earth rails in different periods as well as mainly introduced the technical specifications and industrial production of U76CrREH rail in TB/T 2344.1—2020 standard. U76CrREH rail is the rail with independent design, research and development and production of Baotou Steel as well as with the highest strength grade in China’s railways. The rare earth is mainly used to purify molten steel and refine microstructure in order to achieve the effect of improving fatigue life during service of rails. The industrial production requires narrow composition range as well as adopts such control technologies as low H and O to ensure internal metallurgical quality of rail; its tensile strength ≥1 280 MPa, tread hardness (HB)≥370, microstructure is pearlite and surface quality could meet the technical requirements of standard through adopting such technologies as rolling and cooling technologies of online heat treatment. The rail is applied on small radius curves in Urumqi and has been in service for over three months. The accumulated total through-put weight reaches 30 Mt as well as surface condition and wear of the rail are normal with side wear of 0~0.13 mm.

The field observations and collection of relevant information of curves with different radii are carried out aiming at the rolling contact fatigue (RCF) of U75V heat-treated rail on the curved section of Tangshan-Baotou heavy haul railway. The important characteristics of rolling contact fatigue of rail are obtained through statistics and comparative analysis. Further, the model for initiation of rolling contact fatigue of rail integrating heavy haul train dynamics and damage function model is established to predict the effects of axle load, speed and adhesion coefficient on rolling contact fatigue of rail. It is found that the rolling contact fatigue of rail for up going heavy haul railway is alleviated with the increase of curve radius, there is severe peeling on R600 and R800 curves, the peeling on R1000 curve disappears by and large, while there is just slight cracks on R1600 curve as well as the rail damages of up going heavy haul railway are more serious than those of down going line at no-load. On the section of entering transition curve of up going railway R600, there is obvious peeling when excess of height of inner rail is 55 mm, while there is just sporadic small-size peeling on corresponding outer rail. The numerical simulation results could well explain the phenomena of field observation, which provides the key research tools for further treatment. The curve radius, axle load and profile after wear are determined to be the main influencing factors for rolling contact fatigue of rail in Tangshan-Baotou railway combining with the previous research results.

In this paper, it is mainly introduced the research and development of figured steel for expansion joint of highway bridge (π profile steel) in Rail and Beam Rolling Plant of Baotou Steel to meet the market demands. In order to improve the safety of expansion joint device of highway bridge, the BG355BRE rare earth steel is designed independently to improve strength and toughness of steel. The special pass system is designed aiming at the complex cross section of π profile steel and seriously uneven deformation during rolling process. In the production process, the problem of rolling bending for asymmetric cross section are effectively solved by optimizing pass design and distributing rolling reduction of every pass reasonably. All the mechanical properties of finished products could meet the requirements of technical agreement as well as dimension and surface quality could meet the operating requirements of users so that batch supply is realized.

In order to meet the requirements of carbon equivalent and low temperature toughness, the chemical composition of low temperature Q355C hot rolled H beam for steel structure is designed and reasonable process route is formulated according to the functions of Nb element in steel as well as the mechanical properties of test steel are analyzed based on industrial production data. The test results showed that the yield strength of test steel was 355~465 MPa, tensile strength was stabilized at 525~620 MPa, elongation after fracture was stabilized at over 22% and low temperature impact energy at 0 ℃ was stabilized at 60~160 J by adding Nb element. Finally, the low temperature Q355C hot rolled H beam for steel structure mainly with ferrite and pearlite is obtained as well as all the properties of product could meet standard requirements.

In the paper, it is systematically elaborated the product defects when rolling H beam with universal pass as well as mainly discussed and analyzed from such two aspects as the steel defects and rolling defects of H beam aiming at the rolling process of H beam with universal pass in 1^# production line of Rail and Beam Rolling Plant of Baotou Steel. The steel defects include inclusions, scabs and cracks of product as well as rolling defects include dimension deviation, scratch and bending of product. The treatment methods and optimization measures are put forward according to different types of defects. The amount of waste products caused by unqualified H beam is reduced by taking such measures as reasonably controlling rolling reduction, optimizing guide and controlling rolling speed as well as optimizing control process. As a result, the first pass yield and yield of H beam are improved so that economic benefits are increased.

The armco iron is low carbon steel with such characteristics as soft texture, high toughness and good ductility. The cracks, bending and defects of appearance are easy to occur when rolling flat steel of electrode with armco iron as raw material. Such product defects as dimensional accuracy and cracks for flat steel of electrode are effectively controlled by such measures as improving heating system, optimizing pass and rolling route so that the stable production of products with armco iron is realized.

There is drawing fracture during the process of drawing SWRH82B hard wire rod for users. Its chemical composition, gas content, macrostructure with hot acid of base material and sample of drawing fracture are tested. Moreover, the micro analysis of sample of drawing fracture is carried out with metallographic microscope and scanning electron microscope. The analysis results indicated that since there were abnormal network ferrite structure and band structure of ferrite in the core, their combined action caused fracture of core of SWRH82B during drawing process.

During the process of producing welding wire with BGER60Ti-1 welding wire steel, there is drawing fracture and faint yellow hard block phase is found to be direct cause through metallographic analysis of fracture sample. It is obtained according to formation mechanism of the microstructure that the faint yellow hard block phase is mixture of bainite and martensite. In the paper, such measures as extending holding time of wire rod and improving heat-retaining capacity of temperature holding hood are proposed based on studying from the perspective of controlled cooling after rolling. There is not any hard block phase in the improved matrix structure so that the problem of fracture of wire for BGER60Ti-1 welding wire steel is solved.

In this paper, it is introduced the working principle and technical parameters of regenerative heating furnace in 1^# production line of Long Products Plant, analyzed the characteristics of heat input and output of regenerative heating furnace and ordinary heating furnace, obtained heat balance table and heat efficiency by calculation as well as analyzed the factors affecting heat input and output. Such measures as improving temperature of hot charging and hot delivery of billet and hot charging rate, decreasing temperature of billet out of furnace, using optimal air fuel ratio, reasonably setting commutation cycle, strengthening heat exchange effect in furnace, improving heat exchange efficiency and strictly controlling furnace pressure of regenerative heating furnace are proposed, which are with guiding significances for energy saving and consumption reducing of regenerative heating furnace.