BALDWINS METAL LAND
Frequently Asked Questions
Grade 4.8 bolts have a tensile strength of 400 MPa and a yield strength of 320 MPa (80% of tensile), suitable for general non-critical applications. Grade 8.8 bolts offer tensile strength of 800 MPa and yield strength of 640 MPa, providing double the strength for structural and high-stress applications. The first number indicates tensile strength (multiplied by 100), while the second indicates the yield-to-tensile ratio. Grade 8.8 is recommended for structural steel connections, machinery mounting, and safety-critical applications. Grade 4.8 suffices for non-structural applications like equipment brackets and light fabrication work.
Mixing galvanised and stainless steel fasteners is generally acceptable and avoids galvanic corrosion issues better than using dissimilar metals. However, for optimal corrosion resistance in harsh environments, use stainless steel fasteners (304 or 316 grade) with stainless steel components. For mild steel structures with galvanised coating, galvanised fasteners are the most economical choice. In coastal or highly corrosive environments, consider using stainless steel fasteners throughout for maximum longevity. Always consult structural engineers for load-bearing applications to ensure fastener grade and material meet design specifications.
For general mild steel fabrication, E6013 rods (2.5mm-4.0mm) are versatile all-position electrodes suitable for thin to medium sections, offering easy slag removal and good appearance. For structural work requiring higher strength, E7018 low-hydrogen rods provide superior penetration and crack resistance, essential for critical welds in construction and pressure vessels. E6013 works well for general repairs, light fabrication, and farm equipment. E7018 is specified for structural steel buildings, bridges, and machinery fabrication. Rod diameter selection depends on material thickness and welding position—2.5mm for thin sections, 3.15mm for general work, and 4.0mm for thick materials.