HECO-TOPIX-plus countersunk head HD-20 5,0 x 90, znb

Carbon steel has different mechanical properties depending on the carbon content. Low-carbon steels are weaker and softer but are easily machined and welded, while high-carbon steels are stronger but significantly more difficult to machine. All carbon steels are susceptible to rust, making them unsuitable for many end uses.

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.