Introduction
H-beam steel, also known as High-Frequency Welded H-beam, is defined by its shape, size and weight. It is widely used in the construction and engineering industry and is made out of blocks special steel with hot rolling technology. H-beam steel is most commonly used for structural and reinforcement purposes because it has a good combination of rigidity and strength that allows it to be used in a variety of projects. The Chinese national standard regulation GB/T 11263-1998 specifies the requirements of hot-rolled H-beam steel for the construction and engineering industry.
This standard is divided into three parts. The first part provides general rules for the classification and designation of hot-rolled H-beam steel. The second part gives the technical requirements for the performance of hot-rolled H-beam steel. The third part outlines the relevant test methods for hot-rolled H-beam steel. This standard is applicable to hot-rolled uneven H-beam steel with a nominal width of 75-500mm and a nominal height of 50-500mm.
Size and Grades
The most commonly used sizes of hot-rolled H-beam steel are 250*125, 300*150, 350*175, 400*200, 450*225 and 500*250. The grade of the hot-rolled H-beam steel is based on the steel’s yield point such as grade II, IIA and III. Grade II is the most widely used hot-rolled H-beam steel grade. It is a medium-sized grade that offers good ductility, weldability, strength and machinability for a variety of projects. Grade IIA is a higher grade than II that provides higher strength and higher ductility. Grade III is the highest grade of hot-rolled H-beam steel and offers higher strength and higher ductility than the other two grades.
Chemical Requirements
The chemical composition for hot-rolled H-beam steel is specified in GB/T 11263-1998. It requires the steel to contain carban, other elements such as Silicon, Manganese and Phosphorus, as well as Sulphur and Oxygen. The limit of each element content is specified according to the grade of steel. The total amount of Sulphur and Oxygen needs to be kept within 0.055%, and the total content of Carbon, Silicon, Manganese and Phosphorus needs to be maintained within 0.15%.
Mechanical Properties
The mechanical properties of hot-rolled H-beam steel are regulated by GB/T 11263-1998. It requires the steel to have a minimum yield strength of 235MPa, an ultimate tensile strength of 400MPa and a minimum elongation at break of 15%. The steel should also have a good weldability, formability and surface quality which is free from defects.
Conclusion
Hot-rolled H-beam steel is widely used in the construction and engineering industry due to its good combination of rigidity and strength. The Chinese national standard regulation GB/T 11263-1998 provides the requirements of hot-rolled H-beam steel in terms of size, grade, chemical composition, mechanical properties and other relevant quality criteria. The size and grade of hot-rolled H-beam steel vary according to the steel’s yield point. To ensure the quality of hot-rolled H-beam steel, the total amount of Sulphur and Oxygen needs to be kept within 0.055%, and the total content of Carbon, Silicon, Manganese and Phosphorus needs to be maintained within 0.15%. The steel should also have a minimum yield strength of 235MPa, an ultimate tensile strength of 400MPa and a minimum elongation at break of 15%.
