A2 Stainless Steel Sheet-Metal Self-Tapping Screw — GB/T 845 / ISO 7049 (Series 045) pairs the standard GB/T 845 / ISO 7049 with a A2 Stainless Steel base material. The sections below cover why engineers select this grade for sheet-metal self-tapping screw — gb/t 845 / iso 7049 (series 045), its corrosion and temperature behavior, and the sizes available.
Why Choose A2 Stainless Steel for Sheet-Metal Self-Tapping Screw — GB/T 845 / ISO 7049 (Series 045)
The most common stainless grade for indoor and general outdoor fasteners. For sheet-metal self-tapping screw — gb/t 845 / iso 7049 (series 045), this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | A2-70 (304) |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C |
| Corrosion characteristic | Good general corrosion resistance |
Corrosion Behavior in Service
A2 (304) gives excellent atmospheric and most-water corrosion resistance and is the most common stainless for Sheet-Metal Self-Tapping Screw — GB/T 845 / ISO 7049 (Series 045) in indoor and general outdoor service. In chloride-bearing environments (marine air, road salt, swimming pools) consider stepping up to A4 (316).
Comparable Grades
For Sheet-Metal Self-Tapping Screw — GB/T 845 / ISO 7049 (Series 045), the alternative stainless grade is A4 (316). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.
Sizes of Sheet-Metal Self-Tapping Screw — GB/T 845 / ISO 7049 (Series 045) Available in A2 Stainless Steel
| Size | Nominal diameter (mm) | Pitch (mm) | Length L (mm) | Head diameter dk (mm) | Head height k (mm) | Reference standard |
|---|---|---|---|---|---|---|
| ST2.2 | 2.2 | 0.8 | 9.5 | 4.2 | 1.4 | ISO 1481 / GB/T 845 |
| ST2.9 | 2.9 | 1.1 | 13 | 5.6 | 1.7 | ISO 1481 / GB/T 845 |
| ST3.5 | 3.5 | 1.3 | 16 | 6.9 | 2.1 | ISO 1481 / GB/T 845 |
| ST3.9 | 3.9 | 1.3 | 16 | 7.5 | 2.3 | ISO 1481 / GB/T 845 |
| ST4.2 | 4.2 | 1.4 | 19 | 8.2 | 2.5 | ISO 1481 / GB/T 845 |
| ST4.8 | 4.8 | 1.6 | 25 | 9.5 | 2.9 | ISO 1481 / GB/T 845 |
| ST5.5 | 5.5 | 1.8 | 32 | 10.9 | 3.3 | ISO 1481 / GB/T 845 |
| ST6.3 | 6.3 | 1.8 | 38 | 12.5 | 3.8 | ISO 1481 / GB/T 845 |