The definition of chemical anchor grades: The commonly mentioned 4.8, 5.8, and 8.8 grades represent the performance grades of chemical anchors, which are not necessarily related to the raw materials. For instance, a 4.8-grade chemical anchor signifies a tensile strength of 400MPa, a yield ratio of 0.8, and a nominal yield strength of 400 * 0.8 = 320MPa. A 5.8-grade chemical anchor indicates a tensile strength of 500MPa, a yield ratio of 0.8, resulting in a nominal yield strength of 500 * 0.8 = 400MPa. The calculation for other grades is similar.

Many people are not familiar with the above algorithm. Let's simplify it for you. Taking the commonly used M12*160 chemical anchor bolt as an example, its tensile design value is generally between 16KN and 18KN. If we conservatively take a safety factor of 2.5 times, the maximum tensile value should be between 40KN and 45KN. The 5.8 grade chemical anchor bolt of the M12*160 specification has a tensile strength of over 50KN, which fully meets the requirements, while the 8.8 grade chemical anchor bolt can reach over 80KN.

When selecting chemical anchors, it's not always about the highest tensile strength. On one hand, we have to pay extra for the excessive mechanical properties. On the other hand, as the grade of the chemical anchor increases, its hardness also increases, making it more brittle. It's inevitable to encounter rebar during the installation process, and the only option is to bend the anchor in place, only to straighten it later for actual use, which is difficult for high-grade chemical anchors. The 5.8-grade chemical anchor can even be bent 45° without breaking, whereas the 8.8-grade chemical anchor can only be bent up to 15° (beyond this, it's prone to breaking). In actual construction, curtain wall projects often opt for the 4.8-grade or 5.8-grade chemical anchors, which offer a more balanced performance and better value for money.