Method for producing dual-phase and zinc-aluminum coated steels from plain low carbon steels
AssigneeRa-Shipping Ltd. Oy
InventorPertti J. Sippola
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Abstract
The invention relates to a method for producing coated high strength low alloy steel. A strip of steel is cleaned from rolling oil, is heated to the temperature range A.sub.1 to A.sub.3 in a protective atmosphere, is soaked and subsequently quenched in a zinc-aluminum bath for a short time sufficient to adhere a zinc coating to the steel surface, whereafter the steel strip is rapidly cooled to a temperature below 300.degree. C., to obtain a dual-phase steel structure.
Claims7
A method for producing coated high strength low alloy steel, comprising the consecutive continuous steps of
- cleaning a strip of steel from rolling oil,
- heating the strip in a furnace to the temperature range A.sub.1 to A.sub.3 in a protective atmosphere,
- annealing the strip in a soaking furnace at a temperature in the range of A.sub.1 to A.sub.2,
- quenching the strip in a zinc-aluminum molten metal bath for rapid cooling of the strip to a temperature in the range of 420.degree. C. to 490.degree. C. and for coating the steel with a zinc-aluminum alloy, and
- rapidly cooling the steel strip to a temperature below 300.degree. C. in order to obtain a dual-phase structure.
The method according to any of the preceding claims, wherein the complete quenching time for reaching the temperature below 300.degree. C. is 5 to 10 seconds.
Dependencies are inferred from the claim text.