Iron-carbon master alloy

Patent metadata

Field	Value
Publication number	US-9359662-B2
Application number	US-200913140811-A
Country	US
Kind code	B2
Filing date	Dec 17, 2009
Priority date	Dec 19, 2008
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

An iron-carbon master alloy is described, with a C content of 0.3 to 8 wt % and an upper limit of alloying metals Ni<10 wt %, P<4 wt %, Cr<5 wt %, preferably<1 wt %, Mn<5 wt %, preferably<1 wt %, Mo<3 wt %, W<3 wt %, Cu<1 wt %, a particle size of >20 μm and a hardness of <350 HV 0.01, and a method for the manufacture of said master alloy.

First claim

The invention claimed is:

1. An iron-carbon master alloy comprising a C content of between 0.3 and 8 wt% and an upper limit of alloying metals:
Ni<10 wt %;
P<4 wt %;
Cr<5 wt %;
Mn<5 wt %;
Mo<3 wt %;
W<3 wt %;
Cu<1 wt %;
a particle size of >20 μm, and a hardness of <350 HV 0.01.

2. The iron-carbon master alloy of claim 1 , further defined as comprising Cr<1 wt %.

3. The iron-carbon master alloy of claim 1 , further defined as comprising Mn<1 wt %.

4. The iron-carbon master alloy of claim 1 , further defined as comprising a C content of between 3 and 8 wt %.

5. The iron-carbon master alloy of claim 1 , comprising a C content of between 4 and 6 wt% and an upper limit of alloying metals:
Ni<5 wt %;
P<2 wt %;
Cr<0.5 wt %;
Mn<0.5 wt %;
Mo<1.5 wt %;
W<1.5 wt %; and
Cu<0.5 wt.

6. A method for producing an iron-carbon master alloy of claim 1 comprising:
producing a powdered intermediate product which is rich in C;
annealing the powdered intermediate product which is rich in C, to a temperature of at least 80 ° C. above the γ-temperature of a phase diagram corresponding to the composition of the intermediate product; and
cooling of the intermediate product at at least an initial cooling rate of 3 ° C/min or less.

7. The method of claim 6 , wherein the annealed intermediate product is cooled at a cooling rate of 3 ° C/min or less to a temperature of 500 ° C. then increasing the cooling rate.

8. The method of claim 6 , further comprising preliminarily annealing the intermediate product.

9. The method of claim 6 , further comprising deagglomerating the intermediate product.

10. The method of claim 6 , wherein the powdered intermediate product is produced by atomising a melt of C and Fe or steel.

11. The method of claim 6 , wherein the powdered intermediate product is produced by mixing fine Fe or steel powder with C and subsequent solution annealing.

12. The method of claim 6 , wherein the annealed intermediate product is cooled at an initial cooling rate of 0.5 ° C/min at most.

13. The method of claim 6 , wherein the intermediate product is annealed and cooled in an inert gas atmosphere.

Assignees

• Gierl-Mayer Christian
• Danninger Herbert
• Hemmatpour Yousef
• Univ Wien Tech

Inventors

• Gierl-Mayer Christian
• Danninger Herbert
• Hemmatpour Yousef

Classifications

• C22C38/42

  with copper · CPC title

• C22C38/04 Primary

  containing manganese · CPC title

• C22C38/56

  with more than 1.7% by weight of carbon · CPC title

• C21D1/18

  Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62) · CPC title

• C22C35/005

  based on iron, e.g. ferro-alloys · CPC title