GB/T 33959-2017 in English

Background and Significance of the Standard

With the increasing durability requirements of modern buildings, the demand for stainless steel bars in reinforced concrete structures is increasing. GB/T 33959—2017 "Stainless Steel Bars for Reinforced Concrete" was born to standardize the technical indicators and application requirements of stainless steel bars to ensure their safety and reliability in the fields of construction, transportation, etc.

The standard was proposed by the China Iron and Steel Association and managed by the National Steel Standardization Technical Committee. It combines advanced domestic and foreign experience and technical development needs to provide a scientific basis for the production and use of stainless steel bars.

Comparison of standard frameworks

Technical requirements and practical applications

Chemical composition control: Table 3 specifies the melting composition and finished product allowable deviations of different grades to ensure the corrosion resistance and mechanical properties of stainless steel bars. For example, 06Cr19Ni10 (S30408) requires Cr≥18.0% and Ni≥7.5%.

Mechanical properties: Table 4 lists the yield strength, tensile strength and elongation of different grades. For example, the yield strength of HRB500S is not less than 500 MPa, and the tensile strength is not less than 630 MPa.

Bending and impact properties: The bending test of round steel bars adopts the bending core diameter specified in GB1499.1, while the ribbed steel bars follow GB1499.2. The impact absorption energy is determined by negotiation between the supply and demand parties, but must meet the requirements of GB/T 229.

Test methods and quality control

The standard requires that each batch of steel bars undergo multiple tests such as chemical composition, tensile strength, bending, and intergranular corrosion (see Table 5 and Table 6). In particular, the intergranular corrosion test (GB/T4334-2008 Method E) and the corrosion resistance test (YB/T 4369) are key links in ensuring product quality.

The following measures are recommended during construction:

• Select appropriate stainless steel grades and determine the PREN value according to the design life and use environment (see Appendix A)
• Strictly accept products in the delivery state specified in the standard (hot-rolled pickling or solution treatment)
• Use mechanical connection methods (such as sleeve grouting connection specified in JGJ107) to ensure joint strength

Implementation suggestions and future prospects

With the improvement of environmental protection requirements, the use of stainless steel bars will become more extensive. Recommendations:

1. Fully consider the corrosion resistance requirements in the design stage and reasonably select the grade and diameter
2. Conduct detailed technical disclosure before construction to ensure the implementation of the specifications
3. Establish a long-term monitoring mechanism to track the performance of stainless steel bars in different environments

In the future, it is recommended to further improve the methods for fatigue performance and corrosion resistance evaluation in the standard (see Appendix C and B) to meet the needs of more complex application scenarios.