Lifting eye nuts DIN 582-Steel C15E zinc plated blue M 30

Steel is an iron-carbon alloy with a maximum carbon content of 2% by mass. The steels achieve their intended physical and mechanical properties through various hardening, annealing and tempering processes. It is also possible to harden the edge zone by surface hardening, case hardening or nitriding. Well-known steel grades are structural steels, free-machining steels, case-hardening steels, nitriding steels, tempering steels, tool steels and stainless steels.

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.

Ring nuts and bolts have a large ring on the top and a smooth surface in the lower part, into which an internal thread or a bolt thread is machined. You simply connect the ring nut/bolt to heavy loads for gripping and lifting by tensioning a chain with hooks or a rope. They are used for permanently fastening heavy loads.

According to the chemical composition, C15 (1.0401) is an unalloyed quality steel, C15E (1.1141) is an unalloyed stainless steel, with the difference being the permissible sulfur and phosphorus content. Both types of steel are classified as case-hardened steels depending on their intended use (carbon content less than 0.20%). The materials in this category are characterized in their initial state by good processing properties when machining and forming.