Reinforced Concrete Heat Treatment Steel Reinforcement (GB 1499-91) (I)
Steel reinforcement for reinforced concrete heat treatment is the basis for the manufacture of reinforced concrete construction, and its quality directly affects the intensity and durability of reinforced concrete. The purpose of reinforced concrete heat treatment steel reinforcing bar is to improve its tensile properties, seismic performance and structural safety of reinforced concrete structures. According to the requirements of GB 1499-91, this article introduces the designation of heat treatment steel reinforcing bar, inspection and inspection, general technical requirements and common bar products.
1. Designation of heat-treated steel reinforcing bar
The designation system of heat-treated steel reinforcing bar is based on GB 1499-91, which is composed of four parts and a total of seven characters. The division system of heat-treated steel reinforcing bar is as follows:
Name of steel reinforcement:
The first letter of the designation is the first letter of its name in English, and the letter Y represents heat-treated steel reinforcement. For example, Y represents heat-treated steel reinforcing bar. ;
The second character is a digital character, and the digital character represents the card type.
Type of reinforcing steel bars:
The third character is an alphabetical character, and the alphabetical character represents a kind of steel. It is usually English or English.
Strength of reinforcing steel bars:
The fourth character is a digital character, which represents the national standard strength grade of the steel reinforcing bar.
The fifth character is a numeric character, and the numeric character represents the strength grade of the steel reinforcing bar after heat treatment.
Finishing of reinforcing steel bars:
The sixth character is a letter or number. If it is a letter, it indicates the surface of the steel.
Uses of reinforcing steel bars:
The seventh character is a letter, and the letter indicates the use of the steel.
2. Inspection and inspection
Inspection and inspection of heat-treated steel reinforcing bar include basic inspection and sampling inspection. The basic inspection includes: size inspection, visual inspection and inspection of component mass and content. The sampling inspection includes: sample weight, tensile strength test and steel analysis. According to the inspection requirements of GB 1499-91, the inspection of heat-treated steel reinforcing bar should meet the following requirements:
(1) Check tensile strength: the average value of the three test pieces does not meet the requirements;
(2) The ultimate tensile strength of each sample does not meet the requirements;
(3) The component mass percentage is not in line with the requirements;
(4) There are surface defects such as carbide segregation, cable production, cracks, fins and pins.
3. General technical requirements
According to the general technical requirements of heat-treated steel reinforcement, it should mainly meet the following requirements:
(1) The chemical composition of heat-treated steel reinforcing bar should meet the requirements of GB 1499-91.
(2) The surface of the steel reinforcing bar should be clean and free of serious rust and mill scale. The area and width of the steel reinforcement must meet the requirements of GB 1499-91.
(3) The steel bar should have good delivery, no sampling or bending and no obvious distortion.
(4) The performance of heat-treated steel reinforcing bar should meet the requirements of articles 6 to 10 of GB 1499-91.
4. Common steel products
Common steel products of heat-treated steel reinforcing bar mainly include Ribbed Steel, Light Round Steel and Other Steel bars. The main specifications of each are shown in Table 1.
Table 1 Heat-treated Steel Reinforcing Bar Main Specifications
Steel Products Main Specifications SB500 ribbed bar φ6--φ32 mm LH50 light round bar φ6--φ32 mm Others φ6--φ36 mm
Conclusion
Heat-treated steel reinforcing bar is mainly used to reinforce reinforced concrete. Its quality is directly related to the performance and safety of reinforced concrete structures. This article briefly introduces the designation system, inspection and inspection, general technical requirements and common steel products of heat-treated steel reinforcing bar according to the requirements of GB 1499-91. We hope that people in related industries can use it as a reference.
