High-Temperature Galvanizing Process for Ferrous Material Parts

A method according to any one of the preceding claims,

• wherein the iron-undersaturated zinc melt (12) is not in equilibrium in terms of its iron concentration.

A method according to any one of the preceding claims,

• wherein the iron-undersaturated zinc melt (12) is only temporarily iron-undersaturated, so that the zinc melt (12) automatically moves back to an iron-saturated state or at least towards an iron-saturated state after the ferrous material parts (10) have been dipped into the iron-undersaturated zinc melt (12).

A method according to any one of the preceding claims,

• wherein establishing the undersaturation of the iron concentration of the zinc melt (12) comprises a reduction of the iron concentration.

A method according to any one of the preceding claims,

• wherein the iron saturation concentration of the zinc melt (12) is changed when establishing an undersaturation of the iron concentration.

A method according to any one of the preceding claims,

• wherein establishing the undersaturation of the iron concentration of the zinc melt (12) comprises increasing the temperature of the zinc melt (12).

A method according to any one of the preceding claims,

• wherein the undersaturation of the iron concentration of the zinc melt (12) is adjusted in such a way that, after an initial formation of a galvanization layer (14) on the ferrous material parts (10) during dipping the ferrous material parts (10) into the zinc melt (12), a rate at which the galvanization layer (14) grows and a rate at which the formed galvanization layer (14) is skimmed essentially correspond.

A method according to any one of the preceding claims,

• wherein the undersaturation of the iron concentration of the zinc melt (12) is adjusted in such a way that a resulting layer thickness of the galvanization layer (14) formed upon dipping the ferrous material parts (10) into the iron-undersaturated zinc melt (12) is, at least for total dipping periods between a minimum period and a maximum period, essentially independent of the total dipping duration, wherein the minimum period and the maximum period are each in the order of minutes and differ from each other in the order of minutes.

A method according to any one of the preceding claims,

• wherein the zinc melt (10) has a temperature of at least 500° C., in particular of at least 540° C. and optionally of at least 560° C. and/or a temperature of at most 700° C., in particular of at most 650° C. and optionally of at most 620° C.

A method according to any one of the preceding claims,

• wherein heat is supplied to the zinc melt (12) by means of inductive heating.

A method according to any one of the preceding claims,

• wherein the zinc melt (12) is generated in a ceramic boiler (18).

A method according to any one of the preceding claims,

• wherein a layer thickness of the galvanization layer (14), which is formed when the ferrous material parts (10) are dipped into the iron-undersaturated zinc melt (12), is at most 200 μm, in particular at most 150 μm and optionally at most 100 μm, and/or is at least 30 μm, in particular at least 50 μm and optionally at least 80 μm, on flat and/or uniform surfaces of the ferrous material parts (10), on which the layer thickness is essentially free of accumulation effects due to a geometry of the ferrous material parts (10).

A galvanization line (20) comprising a boiler (18) adapted to accommodate a high-temperature zinc melt and a heating device (22) provided to supply the boiler (18) with the amount of heat required to generate and maintain the high-temperature zinc melt, wherein the boiler (18) and the heating device (22) are specifically adapted to perform therewith a method according to any one of the preceding claims.