In this paper, the bending and bullet-proof properties of steel plate BTP500 are tested. The results of 90° folding test for steel plate BTP500 with thicknesses of 6 mm and 9 mm meet the requirements; the tensile strength of steel plate welded with ferritic welding wire is 100 MPa higher than that of the steel plate welded with austenitic welding wire through comparing the results of performance tests for steel plate BTP500 welded with ferritic welding wire and austenitic welding wire. The impact energy of the test plate welded with ferritic welding wire at -40 ℃ is 20~30 J and the weld test of steel plate BTP500 could meet the agreement requirements. With the penetration of bullet, both of the steel plates BTP500 with thicknesses of 6 mm and 9 mm by industrial trial production are not penetrated, which are with very good bullet-proof and anti-penetration properties as well as the bullet-proof property could meet the agreement requirements.

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.

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.

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, 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.

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 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 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.

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.

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.