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 the paper, it is elaborated the key trial production plan of 550 MPa grade low alloy high strength steel including the chemical composition, hot rolling, cold rolling and annealing processes in detail as well as studied the effects of alloy elements and production processes on microstructure and properties of products. The trial production results showed that the microstructure of 550 MPa grade low alloy high strength steel was mainly composed of ferrite and dispersed precipitated phase of TiC, its main strengthening mechanisms were fine-grain strengthening and precipitation strengthening as well as its yield strength was 556~581 MPa, tensile strength was 622~653 MPa and elongation was 14.0%~16.5%, which could meet the requirements of relevant standards and product applications.

In this article, the different carbon capture technologies, utilization ways and storage technologies of CO₂, demonstration projects and commercial applications of CCUS as well as the challenges facing and development directions are systematically elaborated. Moreover, various carbon capture technologies including the absorption method, adsorption method, membrane separation and other emerging technologies are introduced as well as their feasibility of industrial-scale applications is evaluated by analyzing their principles, advantages and disadvantages; the utilization ways of CO₂ covering such fields as the chemical conversion, fuel production, mineral carbonization and agricultural applications as well as the impacts of different technologies on environmental protection and low carbon economy are discussed. Finally, such technologies as underground storage and ocean storage of CO₂ are elaborated.

In the paper, the relations between such factors as the microstructure of rails, inclusions, excessive hydrogen and residual stress and Crack Length-Cycle curve are analyzed through the data and diagrams obtained by the tests based on the test of threshold value of crack expansion ΔK_th for U71Mn, U75V and U20Mn quenched rails as well as U75V test steel with the rare earth, lanthanum and cerium. Moreover, the effects of adding the rare earth, lanthanum alloy and cerium alloy into rails on crack growth of rails are analyzed, which could provide new means for analyzing the performances of rails and prolonging service life of rails.

The internal audit, as an important part of audit supervision, plays a role of fundamentality and source of self-regulation in the audit supervision system as well as has become the effective complement and extension of national audit. It is the significant problem faced by management layer and internal auditors of state-owned enterprises how to adapt to new circumstances, give play to the supervisory role of internal audit as well as establish the immune mechanism with self-perfection and healthy development within enterprises. In the paper, the practices and experiences of internal audit reform in enterprises are arranged and summarized from such aspects as establishment of auditing offices, construction of audit teams, analysis of auditing cases, audit rectification and achievement transformation of audit as well as the future development direction is pointed out.

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.

The sulfuric acid corrosion resistant steel for railway carriages is with the composition design of low C containing Cr. It is with good comprehensive properties as well as its microstructure is ferrite, bainite and a small quantity of pearlite through the reasonable controlled rolling and controlled cooling process, which could meet the requirements of steel for railway carriages. The scanning electron microscope observation showed that Cu, Cr, Ni and Si were obviously enriched at the interface between oxide layer and matrix of steel. As a result, the adhesive force of oxide layer and matrix is increased to prevent permeation of anions so that the resistance to corrosion of steel surface is enhanced. The corrosion rate of the test steel in the immersion test of 20% sulfuric acid is 6.46 g/(m²·h), which is 20.59% of that of Q355B, so its resistance to sulfuric acid corrosion is excellent.

At present, the climate change has become the threat and challenge globally. As a large carbon emitter, the iron and steel industry is an important part for achieving the goal of peak carbon dioxide emissions and carbon neutrality in our country. The national carbon emission trading market, as a significant policy tool to reduce greenhouse gas emissions, provides the trading platform for contract fulfillment of carbon quota for enterprises. In the paper, the contract fulfillment scheme of carbon emission quota for iron and steel industry into the carbon emission trading market is analyzed based on the current experiences and methods for power industry participating in the carbon emission trading considering six situations that enterprises could face. Moreover, the suggestions are proposed from such aspects as the low carbon management, precision of carbon emission data and applications of low carbon metallurgical technologies to promote enterprises to transform to be green and low-carbon.

In order to improve the engineering construction quality and promote the construction efficiency of building engineering, construction teams need to reasonably apply digital technologies in engineering management process to meet the requirements of current era for engineering management. The feasible application strategies for digital technologies in engineering management could be formulated by analyzing the specific application values of digital management methods and application characteristics of digital technologies to promote effective reform and improvement of construction management, which makes the engineering management play a certain role in ensuring specific engineering construction process to reduce the probability of accidents so that the engineering construction could be completed as planned.

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.