Square washer | A4 | DIN 436

Square washer DIN 436 in acid-proof stainless steel A4 is a durable and reliable washer, designed to provide increased stability and optimal load distribution during installation. It is manufactured from high-quality stainless steel, ensuring long-term resistance to corrosion and the effects of chemical environments. The product complies with the DIN 436 standard and is ready to be used in various construction and industrial applications.

FIELD OF APPLICATION

The square washer according to DIN 436 is primarily used to protect and reinforce fastenings, particularly in wood or other softer materials, where a wider contact surface is needed to avoid deformation. It is ideal for construction, steel structure installation, and in the marine or chemical industries due to its corrosion resistance.

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TECHNICAL SPECIFICATIONS

Product type: Square washer
Standard: DIN 436
Grade: A4 / AISI 316 acid-proof stainless steel
Hardness class: 200 HV
Surface treatment: Untreated

FREQUENTLY ASKED QUESTIONS (FAQ)

What is the main advantage of a square washer according to DIN 436 compared to a round flat washer?

DIN 436 specifies heavy-duty square washers that are specifically designed for timber constructions and heavy-duty joints:

• Maximum contact surface: The square shape provides a significantly larger surface area compared to a standard round washer (DIN 125). It distributes the clamping force from the screw head or nut over a larger area.

• Prevents sinking into the material: When mounting in softer materials such as wood, structural timber, or composite, the washer prevents the nut or screw head from being pulled into the wood and crushing the wood fibers when the joint is tightened firmly.

• Mechanical rotation stop: In narrow channels or beam connections, the straight edge of the washer can rest against an edge or ledge and act as a natural rotation stop during tightening.

Why is acid-proof stainless steel A4 (AISI 316) a good material choice for timber and industrial applications?

Timber constructions and industrial assembly systems outdoors are exposed to constant moisture and chemical influences:

• Durable corrosion protection: A4 steel (1.4401 / AISI 316) does not rust in outdoor environments, coastal and marine environments, damp areas, or upon contact with pressure-treated timber and wood acids.

• No discoloration of the timber: Unlike electro-galvanized washers which eventually corrode and cause unsightly black rust stains in the wood, stainless steel square washers retain a clean surface throughout their service life.

• High bending strength: The generous material thickness according to DIN 436 ensures that the washer does not cup or deform when the bolted joint is tightened with high torque.

In which applications is the square washer DIN 436 most often used?

1. Timber and steel constructions: Perfect for frames, roof trusses, glulam beams, piers, and post fastenings where threaded rods (DIN 976) or hexagon screws pass through heavy timber.

2. Sill and foundation bolting: Widely used between foundation bolts/expansion screws and wooden sills to create a rigid and permanent anchorage.

3. Industrial mounting rails: Fits excellently in slots and channels on profile and mounting systems where square washers are required for correct contact.