# US 8,540,934 B2 · Lead free free-cutting steel and its use

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- Number: US 8,540,934 B2
- Document ID: US8540934B2
- Status: Granted
- Kind: B2
- Application number: 12/449,023
- Filed: 2008-01-24
- Published: 2010-06-10
- Granted: 2013-09-24
- Earliest claimed: 2007-01-26
- Assignees: Sandvik Intellectual Property AB
- Applicants: Mattias Sandström; Ylva Trogen; Lars Karlsson
- Inventors: Mattias Sandström; Ylva Trogen; Lars Karlsson
- Web page: https://patentgrep.com/patent/US8540934B2

## CPC

- C22C 38/54: with boron
- C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/42: with copper
- C22C 38/60: containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A lead free free-cutting steel is described having the following composition in percent by weight: C 0.85-1.2 Si 0.1-0.6 Mn 0.4-1.2 P max 0.05 S 0.04-0.3 Cr max 2 Ni max 1 Mo max 0.5 Cu max 2 Al max 0.1 B max 0.008 Bi+Se+Te max 0.005 Ti+Nb+Zr+V max 0.2 balance Fe and normally occurring impurities. The steel is mainly intended for small/thin dimensions and/or low cutting speeds during manufacture of a product formed of the steel.

## Claims

### Claim 1

Lead free steel consisting of the following composition in percent by weight (wt-%):
C
0.85-1.2
Si
0.1-0.4
Mn
0.4-1.2
P
max 0.05
S
0.04-0.3
Cr
max 2
Ni
max 1
Mo
max 0.5
Cu
max 2
Al
max 0.1
B
max 0.008
Bi + Se + Te
max 0.005
Ti + Nb + Zr + V
max 0.2
balance Fe and normally occurring impurities.

### Claim 2 (depends on 1)

Steel according to claim 1 comprising 0.9-1.1 wt-% C.

### Claim 3 (depends on 1)

Steel according to claim 1 comprising 0.15-0.3 wt-% Si.

### Claim 4 (depends on 1)

Steel according to claim 1 comprising 0.5-1.1 wt-% Mn.

### Claim 5 (depends on 1)

Steel according to claim 1 comprising 0.05-0.25 wt-% S.

### Claim 6 (depends on 5)

Steel according to claim 5 comprising 0.08-0.15 wt-% S.

### Claim 7 (depends on 1)

Steel according to claim 1 comprising maximally 0.5 wt-% Ni.

### Claim 8 (depends on 1)

Steel according to claim 1 comprising 0.3-1.0 wt-% Cu.

### Claim 9 (depends on 1)

Steel according to claim 1 comprising maximally 0.005 wt-% B.

### Claim 10 (depends on 1)

Steel according to claim 1 being essentially free of additions of B.

### Claim 11 (depends on 1)

Steel according to claim 1 being free of additions of Bi, Se and Te.

### Claim 12 (depends on 1)

Steel according to claim 1 being free of additions of Ti, Zr, Nb and V.

### Claim 13 (depends on 1)

Steel according to claim 1 in the form of a wire.

### Claim 14 (depends on 1)

A precision valve comprising a part formed from the steel in accordance to claim 1.

### Claim 15 (depends on 1)

A watch comprising a part formed from the steel in accordance to claim 1.

### Claim 16 (depends on 1)

A measuring probe comprising a part formed from the steel in accordance to claim 1.

### Claim 17 (depends on 1)

A precision tool comprising a part formed from the steel in accordance to claim 1.

### Claim 18 (depends on 3)

Steel according to claim 3 comprising 0.2-0.3 wt-% Si.

### Claim 19 (depends on 4)

Steel according to claim 4 comprising 0.5-0.7 wt-% Mn.

### Claim 20 (depends on 7)

Steel according to claim 7 comprising maximally 0.4 wt-% Ni.

### Claim 21 (depends on 1)

Steel according to claim 1 comprising 0.4 wt-% Si.

### Claim 22 (depends on 1)

Steel according to claim 1 comprising about 0.38 wt-% Si.