Title of Invention

"STEEL FOR COLD FORMING"

Abstract

This invention relates to a steel for cold forming having excellent resistance to wear by abrasion, said steel having the weighted composition: Carbon 1-1.20% Manganese 0.30-0.50% Silicon 0.80-1% Phosphorus <0.020% Sulphur <0.005% Chromium 8-8.50% Nickel <0.30 Molybdenum 2-2.30% Aluminum <200ppm Vanadium 0.20-0.40% Niobium 0.60-0.90% Nitrogen <130ppm Oxygen <30ppm Titanium or Zirconium 500-l000 ppm.,

Full Text

FIELD OF THE INVENTION The present invention concerns a steel for cold forming and offers excellent resistance to wear by abrasion. This steel is obtained by the fusion and refining of a steel and is characterised in that the alloy has the following weighted composition : Preferred bracket Wide bracket Carbon 1 - 1.20% 0.80- 1.50% Manganese 0.30 -0.50% Silicon 0.80 - 1% Phosphorus Sulphur Chromium 8-8.50% 6.25-9% Nickel Molybdenum 2 - 2.30% 1.80- 3% Aluminum Vanadium 0.20-0.40% 0.20-0.40% Niobium 0.60-0.90% 0.60-1.5% Nitrogen Oxygen Titanium or Zirconium 500-1000 ppm 500-1500 ppm The complement being iron plus the impurities characteristic of producing the metal. This steel is worked off via electric fusion followed by refining in a heating ladle, degassing under vacuum and undergoing a remelting process. In this steel, the carbon and niobium form niobium carbide and the titanium or zirconium favour the obtaining of idiomorphous niobium carbide. The stoechiometric ^ y 'ly relation for forming niobium carbide is about 1% of niobium for 0.12% of carbon. The ' excess carbon is balanced by the chromium, molybdenum and vanadium content of the steel. The steel of the invention has a hardness of more than 60 Hrc. It exhibits a combination of qualities : resistance to abrasive wear, machinability and a toughness never previously obtained, Toughness is determined via a measurement according to the Charpy test. A 7xlOx55mm reference test piece is treated at 1050*^0, is stopped in oil, followed by an annealing of two hours at 560°C. For a hardness in excess of or equal to 60 Hrc, it exhibits a rupture energy equal to or more than 40 Joules. The cold forming steel of the invention improves resistance to wear which covers three forms : - abrasive wear, clearly improved, - wear by scaling, clearly improved, by virtue of the excellent toughness of the steel - wear via adherence, also clearly improved. The present invention is not merely limited to the embodiment described and shown, but covers all possible variants. WE CLAIM: 1. A steel for cold forming and obtained via the fusion and refining of an alloy, characterized in that the alloy has the following weighted composition: Carbon 0.80-1.50% Manganese Silicon Phosphorus Sulphur Chromium 6.25-9% Nickel Molybdenum 1.80- 3% Aluminum Vanadium 0.20-0.40% Niobium 0.60-1.5% Nitrogen Oxygen Titanium or Zirconium 500-1500 ppm the complement being iron plus the impurities characteristic of producing the metal. 2. The steel as claimed in claim 1, wherein the alloy has the following weighted composition: Carbon 1-1.20% Manganese 0.30-0.50% Silicon 0.80-1% Phosphorus Sulphur Chromium 8-8.50% Nickel Molybdenum 2-2.30% Aluminum Vanadium 0.20-0.40% Niobium 0.60-0.90% Nitrogen Oxygen Titanium or Zirconium 5 00-1 OOOppm the complement being iron plus the impurities characteristic of producing the metal.

Documents:

216-MAS-1998 ABSTRACT.pdf

216-MAS-1998 CLAIMS GRANTED.pdf

216-MAS-1998 DESCRIPTION (COMPLETE) GRANTED.pdf

216-mas-1998 abstract.pdf

216-mas-1998 claims.pdf

216-mas-1998 correspondence others.pdf

216-mas-1998 correspondence po.pdf

216-mas-1998 description(complete).pdf

216-mas-1998 form-1.pdf

216-mas-1998 form-19.pdf

216-mas-1998 form-2.pdf

216-mas-1998 form-26.pdf

216-mas-1998 form-3.pdf

216-mas-1998 form-4.pdf

216-mas-1998 petition.pdf