Washer M12 DIN 125 A4 140 HV 13

Why choose A4-80 steel? Grade A4 (AISI 316) contains molybdenum, which provides exceptional resistance to pitting and crevice corrosion – significantly superior to standard A2 steel. A hardness of 140 HV ensures high resistance to deformation and even distribution of clamping forces.

When to choose A4-80 over A2-70? Stainless steel grade A4 is essential wherever contact with seawater, chlorides, acids or other aggressive media is present. It is the standard choice for photovoltaic installations in coastal zones, swimming pools, the chemical industry and the food processing sector.

Compliance with DIN 125 means standardised dimensions and tolerances, ensuring full compatibility with M12 metric bolts and nuts. The washer is reusable and fits all standard M12 bolted connections.

Technical Specifications

• Standard: DIN 125 (equivalent to ISO 7089/7090)
• Size: M12
• Hole diameter (d1): 13 mm
• Material: stainless steel grade A4 (AISI 316)
• Hardness: 140 HV
• Type: plain flat washer

Applications

• Photovoltaic installations: securing mounting structures and fastening elements exposed to corrosion, particularly in coastal zones with elevated environmental aggressiveness
• Steel structures: external and internal bolted connections in aggressive environments
• Mechanical engineering: machinery and equipment requiring high resistance to chemical agents
• Agriculture: equipment exposed to moisture, fertilisers and crop protection products
• Construction: façade and fixing elements in damp or contaminated environments

The function of a washer – it increases the bearing surface, protects the joined material from damage and prevents the connection from loosening. An essential component of every professional bolted joint.