Resources
Glossary
A4 Stainless Steel
Class A4 stainless steel is a metric fastener designation defined under ISO material specifications and is typically associated with austenitic stainless steel similar to Grade 316. In addition to chromium and nickel, it contains molybdenum, which provides enhanced resistance to corrosion, particularly in chloride-rich environments.
A4 stainless steel fasteners are often referred to as marine-grade fasteners due to their durability in saltwater, chemical, and harsh outdoor environments. In fastener applications, A4 stainless steel is commonly used in marine, coastal, chemical, and outdoor structural settings where high corrosion resistance is required.