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.

In the paper, the dimension parameters of sizing mill and its corresponding hot tool, sizing mill stand are optimized and designed with the software, ultimate machining dimension of sizing mill stand is calculated as well as pass design of rolling specifications within ultimate dimension and theoretical analysis on optimization of rolling parameter are carried out with the numerical simulation technology and existing equipment status. The ultimate specifications of replacing stretch reducing mill with sizing mill are obtained by comparing relevant parameter design of stretch reducing mill for rolling with the same specification as well as comprehensively analyzing the status of host of equipment and production efficiency, which could provide reliable theoretical support for promoting replacing stretch reducing mill with sizing mill for rolling.

In the paper, the composition design and industrial trial production process of BNS, X60QS and X65QS grade acid corrosion-resistant line pipe are introduced, the effects of normalizing, quenching and tempering processes on metallographic structure and mechanical properties of the hot rolled steel pipe are studied as well as acid corrosion resistance of the product is analyzed. The trial production results showed that the mechanical properties and acid corrosion resistance of BNS grade line pipe produced with normalizing process as well as X60QS grade and X65QS grade line pipes produced with quenching and tempering process could fully satisfy the API Spec 5L standard requirements.

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 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.

In this paper, the causes of defect of longitudinal crack on surface of Q420NQR1 continuous casting billet and rolled products with hypo-peritectic steel are analyzed as well as the control measures are put forward. The results indicated that the defect of longitudinal cracks for rolled products originated from longitudinal cracks on surface of casting blank, most of which were on the web of beam blank away from submerged entry nozzle. The inner flow field of crystallizer is studied by physical simulation. It is found that there is single circulation flow on the web of crystallizer, which directly causes the melt cinder layer of casting powder away from submerged entry nozzle to be thinner so that effective heat control is difficult to be realized at this position. The flow velocity of surface layer of liquid steel could be reduced and even distribution of melt cinder could be promoted through appropriately increasing the insertion depth of submerged entry nozzle; the quality of casting blank and rolled products could be improved combining with the uneven burden distribution mode of casting powder so that the longitudinal crack rates of casting blank and rolled products are reduced by 30% and 34% respectively.

In order to solve the difficult problem for long distance transmission of large scale hydrogen energy with low costs, the X52M hot rolled steel strip for pipeline added with hydrogen is designed, researched and developed as well as its engineering applications are realized. It is with the design of low C and Mn, Nb and Ti alloying, extreme low contents control of P and S as well as smelting with high cleanliness and reasonable controlled rolling and cooling process. It is with excellent comprehensive performances, good low temperature toughness and resistance to hydrogen brittleness. Its dimensional precision is high and surface quality is good so that the properties of pipe body and weld seam could meet the requirements and satisfy the operating requirements of steel pipe. It is applied in the Baotou-Linhe gas pipeline for western natural gas so that the first pipeline engineering application of spiral submerged arc welded pipe added with hydrogen is realized.

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.

With the rapid development of society, the requirements of market for quality and performance of steel products are constantly increasing. The competition in the steel industry is increasingly fierce. The stable product quality is an effective way to improve market competitiveness on the basis of ensuring supply on time. In the paper, it is introduced such problems as unstable product quality and high costs are solved as well as the reform and exploration of quality management on new models of professional user-centered quality management and contract-centered steel rolling management are carried out for Baotou Steel Union Co., Ltd. in order to improve the market competitiveness of products. As a result, the stability of product quality and production efficiency are increased so that good economic benefits are created.

The thermos mechanical control process (TMCP) has been difficult to apply in the field of seamless steel pipe. The control cooling equipment after rolling is developed combining with process flow of seamless steel pipe, the X52N seamless pipeline steel pipe is produced with on-line accelerated cooling after rolling through industrial practices as well as its physical and chemical properties and microstructure are studied. The practices showed that the costly alloy elements did not need to be added into the production with C-Mn steel, microstructure of material was regulated and controlled by on-line accelerated cooling after rolling so as to ensure mechanical properties of material to meet the standard requirements as well as follow-up offline heat treatment was not needed. As a result, the requirements of physical and chemical properties for long distance pipeline steel pipe X52N could be met so that low cost, short process and economic production are realized.