A4-80 Stainless Steel Bolt
A4-80 stainless steel bolts are high-strength stainless steel fasteners designed for applications that require both excellent corrosion resistance and higher mechanical strength. As an A4 stainless steel fastener grade, A4-80 contains molybdenum (Mo), which provides better resistance to moisture, chlorides and other corrosive environments than A2 stainless steel. The “80” designation indicates a minimum nominal tensile strength of 800 MPa, giving A4-80 bolts a higher strength level than A4-70 bolts.
A4-80 bolts are a suitable choice when standard stainless steel fasteners need to withstand demanding environments while providing greater load-bearing capability. They are commonly used in marine and coastal equipment, industrial machinery, processing systems, construction and other applications where both corrosion resistance and mechanical strength are important. A4-80 stainless steel bolts can be produced in different diameters, lengths and thread specifications to meet different fastening requirements.
Type of A4-80 Bolt:
A4-80 stainless steel bolts are available in several designs to accommodate different fastening and assembly requirements. We can provide hex bolts, flange bolts, carriage bolts, anchor bolts, T-bolts and U-bolts in a variety of diameters, lengths and thread specifications. Standard sizes as well as custom dimensions can be produced according to drawings or specific application requirements.
The higher strength of A4-80 bolts is achieved through cold working of the austenitic stainless steel, rather than by using a fundamentally different stainless steel material group. During production, the raw material condition and cold-working process are carefully controlled to achieve the required A4-80 mechanical properties while maintaining consistent dimensions and thread quality. We also control key manufacturing processes and inspections to ensure that finished bolts meet the specified requirements.
Material Chemical Composition of A4-80 Bolt:
A4-80 stainless steel bolts are commonly manufactured from 316 or 316L stainless steel, which are widely used for A4 stainless steel fasteners. The addition of molybdenum (Mo), together with chromium and nickel, provides enhanced corrosion resistance, particularly in humid and chloride-containing environments. Learn more about our 316 stainless steel bolts and their material characteristics on our dedicated product page.
The chemical composition of A4-80 bolt material is controlled according to the applicable material and fastener standards. Key elements include carbon, silicon, manganese, phosphorus, sulfur, chromium, nickel and molybdenum, with the required limits depending on the specified stainless steel grade.
| Property Class | Chemical Compistion(max) | |||||||||
| C | Si | Mn | P | S | Cr | Mo | Ni | Cu | N | |
| A4-80 | 0.08 | 1 | 2 | 0.045 | 0.03 | 16.0~18.5 | 2.00~3.00 | 10.0~15.0 | 4 | / |
Mechanical Property of A4-80 Bolt:
A4-80 stainless steel bolts are classified as austenitic stainless steel fasteners with a minimum nominal tensile strength of 800 MPa according to ISO 3506-1. The A4-80 property class also requires a minimum stress at 0.2% non-proportional elongation of 600 MPa and a minimum elongation after fracture of 0.3d. These requirements define the strength and ductility of A4-80 bolts and make them suitable for applications where higher mechanical strength is required together with the corrosion resistance of A4 stainless steel.
| Property Class | Tension Strength(min)MPA | Stress at 0.2% non-proprotional elongation(min)MPA | Elongation after fracture(min)mm |
| A4-80 | 800 | 600 | 0.3d |
Application of A4-80 Bolt:
Heavy-Duty Machinery & Equipment
A4-80 stainless steel bolts are suitable for heavy-duty machinery and industrial equipment where fastening connections require higher mechanical strength as well as good corrosion resistance. They can be used for equipment frames, structural components, machine assemblies, pumps and other heavily loaded connections. The 800 MPa minimum tensile strength of A4-80 provides additional load-bearing capability compared with A4-70 fasteners.
Marine & Offshore Equipment
The combination of A4 stainless steel corrosion resistance and A4-80 mechanical strength makes these bolts suitable for marine, offshore and coastal equipment. Typical applications include marine machinery, deck equipment, brackets, structural assemblies and outdoor installations exposed to moisture and chloride-containing environments. A4-80 provides a practical fastening option when both corrosion resistance and higher strength are required.
Industrial Structures & High-Load Connections
A4-80 bolts can be used in industrial structures and equipment where fastening connections are subject to higher loads or demanding operating conditions. They are suitable for construction equipment, processing machinery, support structures, tanks and other assemblies requiring durable stainless steel fastening. The higher strength level of A4-80 allows designers to consider a stronger A4 stainless steel fastener where A4-70 does not provide sufficient mechanical capacity.