The effects of annealing temperature on microstructure and hardness of hot-dip galvanized low alloy high strength steel strip HC420LAD+Z are analyzed through thermal simulated test machine, optical microscope and hardness test as well as it is concluded that its recrystallization temperature is 700 ℃. The changes of microstructure and properties of the steel strip at different annealing temperatures are further discussed combining the industrial productions with the measured recrystallization temperature. The results showed that the mechanical properties of steel strip were the best when annealed at 780 ℃, yield strength was 467 MPa, tensile strength was 508 MPa, elongation was 24% and the surplus was moderate, which could meet the requirements of EN 10346-2015 standard and customer use.

The independent research and development has been carried out by Baotou Steel based on the technical requirements of hot rolled coil with high strength and corrosion resistance for railway carriages. The mechanical properties and corrosion resistance of the test steel all meet technical requirements through adopting the system of low carbon+copper chromium nickel alloy and appropriate controlled rolling and controlled cooling processes. The trial production results showed that its yield strength was 550~580 MPa, tensile strength was 645~690 MPa, elongation after fracture was 20.0%~22.0%, low-temperature impact absorbing energy at -40 ℃ was 202~255 J and microstructure at room temperature was ferrite+pearlite+bainite, which was with excellent matching of strength and toughness. Its average corrosion rate is 2.813 5 mm/a, while that of Q235B is 36.060 5 mm/a, so its corrosion rate is 7.8% of that of Q235B.

The cracking sample of flash welded wheel steel 380CL for rim is detected and analyzed with optical microscope and microhardness tester. The results showed that the content of C in wheel steel 380CL exceeded the upper limit of internal control, heat with high temperature in the weld region during flash welding was fast, cooling speed was fast after weld, hardenability of weld region was improved and coarse bainite structure appeared; the microhardness of matrix and heat affected zone (HV0.1) was 303~310, while that of weld region (HV0.1) was 346, which was 12%~14% higher than that of matrix and heat affected zone, so the hardness difference was greater and ability of deformation coordination of each structure was poor when the rim flared and deformed so that they were cracked at the junction of weld seam and coarse grain heat affected zone. The weld microstructure could be refined, hardness difference of weld, matrix and heat affected zone could be reduced by strictly controlling the chemical compositions of wheel steel 380CL and reducing welding heat input so that good plasticity of weld could be ensured and cracking rate of forming for rim could be reduced.

In recent years, great progress has been made in the production technology of heat treatment for steel plate with limit specifications. The production technologies of heat treatment for steel plate with limit specifications at home and abroad are compared and introduced. The intensive production technology of heat treatment with roller quenching is adopted in China, the trial production of the thinnest steel plate (2 mm) as well as continuous and stable productions of the thickest steel plate (300 mm) have been achieved, which gradually surpass the production technologies of heat treatment adopted abroad, temperature control quenching and water tank quenching. As a result, significant contributions have been made to the large-scale, lightweight and long-service life equipment manufacturing as well as adapting to complex and harsh service environment in China.

In the paper, the technical requirements, production process control and quality performances of seamless steel pipe BT770 for crane boom produced by Baotou Steel are introduced. The seamless steel pipe BT770 for crane boom produced with the full process production process of “continuous casting billet+PQF continuous rolled seamless steel pipe+quenched-tempered heat treatment” and treatment process of external surface for steel pipe are with higher strength and toughness, good low temperature impact toughness, welding performances and surface quality.

The chemical compositions of seamless steel pipe with wall thickness greater than 25 mm for X65Q grade line pipe are designed based on low-C Mn containing steel with microalloying technology and the optimum heat treatment process is determined by laboratory study. The test results showed that the strength and low temperature impact toughness of the material matched well with the heat treatment process of “910 ℃ quenching+670 ℃ tempering”, microstructure in the steel was mainly bainite+a small quantity of tempered sorbite, grain size was 8.5 grade; low temperature impact energy of the material at -30 ℃ was over 120 J and surplus of yield strength of the material was about 80 MPa through industrial batch production testing so that the designed steel grade could be used in productions of X65Q or higher grade line pipe with wall thickness greater than 25 mm, which could meet the requirements of related performance indexes of users.

In order to study the relations between straightening process and residual stress of rails, the stress-strain situation of rails during straightening process is simulated combining with the ABAQUS software of finite element analysis. Various straightening process plans of rails are with simulation analysis to determine the optimal one and are researched combining with the results of on-site process debugging. The results showed that the minimum elastic core of each straightening plan was within deformation zoneⅡ, so the residual stress of rails could be effectively reduced by reducing the rolling reduction of 2^# and 4^# straightening rolls as well as straightening speed of rails.

The chemical composition, heating and rolling processes of hot rolled beam SM490YB are reasonably designed according to the technical standard requirements of hot rolled H beam SM490YB for offshore oil platforms in the Japanese Standard JIS G 3106-2020 “Rolled Steel for Welded Structures” combining with the characteristics of working conditions of production line in steel plant. The yield strength of the test steel with Nb-V microalloying is 412~420 MPa, tensile strength is 531~545 MPa, elongation after fracture is 26%~29%, longitudinal impact absorbing energy at -20 ℃ is greater than 200 J and transverse impact absorbing energy is greater than 110 J; microstructure of the test steel at room temperature is fine ferrite+pearlite and grain size number of ferrite is 8.5. The test results showed that the H beam with Nb-V microalloying was with good comprehensive mechanical properties, which could meet the requirements of high strength and toughness, low temperature resistance and easy to be welded for the steel for offshore oil platforms.

The composite robot consists of moving chassis with autonomous navigation and robot arm. The moving chassis is with the move function, while robot arm is with the grasping ability. Their mutual integration enables composite robots to perform more complex actions. In this article, it is developed the industrial handling system for composite robot based on the robot operating system (ROS) framework, focused on the problems of handling control and autonomous navigation with tracking for the system as well as explored how to improve its handling efficiency and accuracy. The composite robot could accurately perform handling tasks of workpieces by designing and implementing a reliable strategy of control and autonomous navigation.

In the article, the loader and unloader as well as process flow of walking beam cooler for wide and thick plate are introduced. The production status is that there is scuffing of plate during the lateral moving process of plate in walking beam cooler of production line of wide and thick plate in CSP Plant of Baotou Steel as well as plates are seriously skewed when lateral moving to the exit position so that unloading of plate cannot be carried out. The reason is the equipment wear of walking beam cooler in long-term use through analyzing, resulting in slight differences of each step of lateral moving in the two zones of cooling bed so that the cumulative deviations during the whole lateral moving process are too large. As a result, the plates are skewed in lateral moving process. The solution of compensating slight differences of each step of lateral moving in the two zones of cooling bed by adding the absolute value encoder and revision program is proposed.