AU733190B2

AU733190B2 - Steel for cold forming

Info

Publication number: AU733190B2
Application number: AU52893/98A
Authority: AU
Inventors: Jacques Adrien; Bertrand Remi
Original assignee: Thyssen France SA
Current assignee: Thyssen France SA
Priority date: 1997-02-04
Filing date: 1998-02-03
Publication date: 2001-05-10
Anticipated expiration: 2018-02-03
Also published as: CN1087038C; PT856591E; DE69801241T2; FR2759092A1; EP0856591B1; ES2161506T3; KR19980071037A; SI9800030A; CN1200411A; AR011620A1; CA2226350A1; HK1016657A1; KR100487086B1; ATE203784T1; ZA98725B; DE69801241D1; CA2226350C; CO4930308A1; FR2759092B1; MY117322A

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

S

Invention Title: STEEL FOR COLD FORMING The following statement is a full description of this invention, including the best method of performing it known to us: GH REF: P25523-A:GS:RK 2 FIELD OF THE INVENTION The present invention concerns a steel for cold forming and which 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 weight composition by weight: Preferred Range 0.

0 0 0 0 *1 0 0 00 :..00 0:0:: 0.0.: 00 Carbon Manganese Silicon Phosphorus Sulphur Chromium Nickel Molybdenum Aluminum Vanadium 20 Niobium Nitrogen Oxygen Titanium or Zirconium 1 1.20 0.30 0.50% 0.80 1% 0.020% 0.005% 8 8.50% 0.30% 2 2.30% 200ppm 0.20 0.40% 0.60 0.90% 130 ppm 30 ppm 500-1000 ppm Broad Range 0.80 1.50% 1% 1% 0.030% 0.005% 6.25 9% 0.50% 1.80 3% 0.15% 0.20 0.40% 0.60- 150 ppm 50 ppm 500-1500 ppm With the balance being iron plus impurities characteristic of producing the metal.

This steel is produced preferably by 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 relation for forming niobium carbide is about 1% of niobium for 0.12% of carbon. The 29104.doc 3 excess carbon is balanced by the chromium, molybdenum and vanadium content of the steel.

Steels emboding the invention have been found to produce a hardness of more than 60 Hrc, and 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 10500C, is stopped in oil, followed by an annealing of two hours at 5600C. 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, go wear by scaling, clearly improved, by virtue of the 20 excellent toughness of the steel wear via adherence, also clearly improved.

The present invention is not merely limited to the embodiment described, but covers all possible variants falling within the spirit and scope of the invention.

Furthermore, the invention may be defined as consisting in a method of producing steel in any one of the forms described above and product formed by cold forming from such steels.

29104.doc

Claims

1. Steel for cold forming and obtained by fusion and refining of an alloy, characterised in that the alloy has the following composition by weight: Carbon Manganese Silicon Phosphorus Sulphur Chromium Nickel Molybdenum Aluminium Vanadium Niobium Nitrogen Oxygen Titanium or zirconium 0.80 1.50% 1% 1% 0.030% 0.005%

6.25 9% 0.50% 1.80 3% 0.15% 0.20 0.40% 0.60 150 ppm 50 ppm

500-1500 ppm a a a With the balance of producing the being iron plus impurities characteristic metal. 2. Steel according to claim 1, characterised in that the alloy has the following weight composition: Carbon Manganese Silicon Phosphorus Sulphur Chromium 1 1.20 0.30 0.50% 0.80 1% 0.020% 0.005% 8 8.50%

29104.doc 5 Nickel Molybdenum Aluminium Vanadium Niobium Nitrogen Oxygen Titanium or Zirconium 0.30 2 2.30% 200ppm 0.20 0.40% 0.60 0.90% 130 ppm 30 ppm 500-1000 ppm The balance being iron plus impurities characteristic of producing the metal. 3. Steel as claimed in claim 1 or claim 2 and wherein it is produced by electric fusion followed by refining in a heating ladle, degassing under vaccuum and remelting in a remelting process. 4. Steel as claimed in any one of the preceding claims and having a toughness determined by a Charpy test of more than A steel product produced by cold forming a steel as claimed in any one of the preceding claims. 6. A method of producing steel as claimed in any one of the preceding claims comprising taking an alloy having the following composition by weight: Carbon Manganese Silicon Phosphorus Sulphur Chromium Nickel Molybdenum 0.80 1.50% 1% 1% 0.030% 0.005% 6.25 9% 0.50% 1.80 3% 29104. doc 6 Aluminium Vanadium Niobium Nitrogen Oxygen Titanium or zirconium 0.15% 0.20 0.40% 0.60 150 ppm 50 ppm 500-1500 ppm With the balance being iron plus impurities characteristic of producing the metal, effecting fusion of the alloy and refining the alloy. Dated this 7th day of March 2001 THYSSEN FRANCE SA By their Patent Attorney GRIFFITH HACK *e e o e oo o 77 3( 4,? 29104.doc