FAQs on Stainless Steel & Aluminum Fastener Selection

Q1：Will aluminum screws / aluminum bolts rust when used outdoors?

Unfinished aluminum fasteners will oxidize and form white powdery corrosion. We supply free anodizing treatment for aluminum fasteners. After sealing anodizing, it can pass ≥480h salt spray test and remain corrosion-free for 5 years in outdoor service.

Q2：Can 304 / 316 stainless steel fasteners meet food-grade requirements?

Yes. Our 304 and 316 stainless steel fasteners can pass FDA food contact certification. We adopt food-grade lubricants during thread rolling and forming, to avoid contamination for food machinery and catering equipment.

Q3：What is the difference between 304(A2) and 316(A4) stainless steel fasteners?

Both are corrosion-resistant. 316 (A4) contains molybdenum and performs far better against chloride, ideal for coastal, salt water and seafood processing equipment. 304 (A2) is cost-effective for general indoor and normal outdoor fastening.

Q4：Can anodized aluminum fasteners be customized in different colors? Will it affect salt spray performance?

Custom colors such as black, gold and bronze are available for aluminum fastener anodizing. Colored anodizing with proper sealing keeps the ≥480h salt spray resistance unchanged.

Q5：Is there a galvanic corrosion risk when stainless steel fasteners clamp aluminum parts?

Yes, galvanic corrosion risk exists in humid or salt spray environment. We recommend using insulating washers or anodized isolation to separate the contact surface of stainless steel fasteners and aluminum substrates.