Wing nuts DIN 315-Malleable zinc plated blue M 4

Wing nuts are manufactured according to DIN 315. There are two forms. The small (American) wing shape is smaller, requires less material to produce and is therefore cheaper. The large wing shape of the wing nuts is also called the German shape. It has nice, rounded wings and looks better for most applications.

The raw material for malleable cast iron is molten iron containing approximately 3 per cent carbon, 1 per cent silicon and 0.5 per cent manganese. A distinction is made between decarburised malleable cast iron (abbreviation: EN-GJMW) and non-decarburised malleable cast iron (abbreviation: EN-GJMB). Both types of malleable cast iron are considerably tougher than cast iron and are easy to cast. The special grade of malleable cast iron EN-GJMW-360-12 is weldable.

Blue galvanised finishes are produced either by electroplating in accordance with DIN EN ISO 4042 or by mechanical plating in accordance with DIN EN ISO 12683. For fasteners with a hardness exceeding 390 HV, there is a risk of hydrogen embrittlement during galvanising (electrolytic process). This necessitates specific measures (such as annealing), although these do not provide a 100 per cent guarantee against embrittlement.