Reinforcement length and allowable deviation after heat treatment (GB 13014-1991)

The length and allowable deviation of heat-treated bars are regarded as having a great influence on the performance of the bars. It is therefore very important to exercise proper control over these properties of the bars during production. The length and allowable deviation of heat-treated bars are specified in GB 13014-1991, which is a national standard of the People’s Republic of China.

The standard specifies the length and tolerances of the heat-treated bars produced by the national hot rolling industry. According to this standard, for steel bars of hot rolling or thermal treatment with a diameter of 8mm to 235mm, the length should not be less than 7.5 m, and should not be more than 13 m. The allowable deviation of the length should not exceed 0.05 percent of the length specified in the contract, or 10mm, whichever is greater.

In addition, in the table specified by GB 13014-1991, the length and allowable deviation of steel bars with a diameter greater than 80mm should also be given in the form of standard length. For example, the length of a steel bar with a diameter of 120 mm is 12 m, and the allowable deviation should not exceed 0.05 percent of the length specified in the contract, or 20mm, whichever is greater. Therefore, it is necessary to strictly control the length and allowable deviation of the steel bars during production.

The allowable deviation of the cross section of the heat-treated bars is also specified in GB 13014-1991. According to this standard, the allowable deviation of the cross section of the heat-treated bars should not exceed 5 percent of the cross sectional area specified in the contract. For example, for a steel bar with a nominal cross sectional area of 60mm2, the allowable deviation should not exceed 3mm2.

In addition to the length and allowable deviations of heat-treated bars, other properties of the bars must also be ensured. According to the national standard GB 13014-1991, the tensile strength, yield strength, and elongation of the bars should meet the requirements specified in the standard.

In conclusion, it is important to understand and observe the length and allowable deviations of heat-treated steel bars as stipulated in GB 13014-1991. It is also necessary to ensure all other requirements to guarantee the performance of the bars.

The GB 13014-1991 standard is a national standard for remaining heat treatment of steel bars and related permissible deviations. According to this standard,the allowable input length,the total length,the allowable deviation of section size, the allowable deviation of length and the allowable deviation of roundness of the steel bars after heat treatment should meet the corresponding requirements.

The allowable length of the remaining heat treatment of steel bars is 8m. The total length can range from 8m to 12m. The size of the cross section should meet the corresponding requirements. In addition, the allowable deviation range of lateral dimension of steel bars should also be controlled. And,the surface should be smooth, no wrinkles and bumps and evenly distributed.

The allowable deviation of length should be within (-0.3mm,-3mm). And the roundness of the steel bars should meet the requirements. The deviation of roundness should be within ±1mm. In addition, after heat treatment,metal materials (such as steel bars) should be cleaned to remove dirt,oil and other dirt.

In summary, according to the GB 13014-1991 standard,the remaining heat treatment of steel bars should meet corresponding requirements,including the allowable length and permissible deviation of the cross section,the allowable deviation of length and the allowable deviation of roundness. The requirements ensure the quality and performance of the steel bars after heat treatment.