Co-based wire and method for saw tip manufacture and repair

1 . A Co-based saw tip alloy for the formation of a saw tip on a saw blade, the alloy comprising, by approximate wt %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

  0-1.57

Co

Balance;

wherein the total concentration of boron and carbon is between about 1.2 wt % and about 2.5 wt %;

wherein the Si has a concentration no greater than about (1.8−(0.12*[Mo])+(0.1*([B]+[C]))).

2 . The Co-based saw tip alloy of claim 1 wherein the alloy is prepared in a form selected from the group of forms consisting of powder metallurgy preforms in the shape of saw tips, powder metallurgy pre-shaped rods for tipping saw blades, cast rods for welding onto saw blades, and wires for welding onto saw blades.

3 . The Co-based saw tip alloy of claim 1 consisting essentially of, by approximate weight %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

 0.1-1.57

Mn + Ni + Fe

 0-10

W

1-4

Co

Balance.

4 . The Co-based saw tip alloy of claim 1 wherein the Si has a concentration between about 0.1 wt % and about 1.4 wt %.

5 . The Co-based saw tip alloy of claim 1 , wherein the alloy is used for the formation of saw tips on saw blades for cutting wood, the alloy consisting essentially of about 1.2 wt % C, about 0.5 wt % B, about 29 wt % Cr, about 8.5 wt % Mo, from about 0 to about 10 wt % elements selected from the group consisting of Mn, Ni, and Fe, between about 0.1 and about 1.4 wt % Si, and the balance being Co.

6 . A tubular wire for the formation of a saw tip on a saw blade, the tubular wire comprising metal powder of the elements C, B, Cr, Mo, and Si within a Co-based sheath in proportions which provide an alloy comprising the following constituents by weight upon melting of the tubular wire, by approximate weight %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

 0.1-1.57

Co

Balance;

wherein the total concentration of boron and carbon is between about 1.2 wt % and about 2.5 wt %;

wherein the Si has a concentration no greater than about (1.8−(0.12*[Mo])+(0.1*([B]+[C]))).

7 . The tubular wire of claim 6 consisting essentially of, by approximate weight %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

 0.1-1.57

Mn + Ni + Fe

 0-10

W

1-4

Co

Balance.

8 . The tubular wire of claim 6 , wherein the outer diameter of the wire is between about 0.8 mm and about 4 mm.

9 . The tubular wire of claim 6 wherein the Si has a concentration between about 0.1 wt % and about 1.4 wt %.

10 . The tubular wire of claim 6 , wherein the tubular wire is used in the formation of saw tips on saw blades for cutting wood, the tubular wire consisting essentially of:

a Co-based sheath comprising about 95 wt % Co, 2.5 wt % Ni and 2.5% Fe; and

metal powder within the sheath, the metal powder consisting essentially of the elements C, B, Cr, Mo, Mn, and Si in proportions that provide an alloy comprising the following constituents upon melting of the tubular wire:

about 1.2 wt % C, about 0.5 wt % B, about 32 wt % Cr, about 1.3 wt % W, about 18 wt % Mo, from about 0 to about 10 wt % elements selected from the group consisting of Mn, Ni, and Fe, between about 0.1 and about 1.4 wt % Si, and the balance being Co.

11 . A Co-based saw tip for a saw blade, the saw tip comprising, by approximate weight %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

 0.1-1.57

Co

Balance;

wherein the total concentration of boron and carbon is between about 1.2 wt % and about 2.5 wt %;

wherein the Si has a concentration no greater than about (1.8−(0.12*[Mo])+(0.1*([B]+[C]))).

12 . The Co-based saw tip of claim 11 consisting essentially of, by approximate weight %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

 0.1-1.57

Mn + Ni + Fe

 0-10

W

1-4

Co

Balance.

13 . The Co-based saw tip of claim 11 wherein the Si has a concentration between about 0.1 wt % and about 1.4 wt %.

14 . The Co-based saw tip of claim 11 consisting essentially of about 32 wt % Cr, about 8.5 wt % Mo, 0 wt % W, from about 0.3 to about 2.4 wt % C, from about 0.1 to about 1.0 wt % B, from about 0 to about 10 wt % elements selected from the group consisting of Mn, Ni, and Fe, between about 0.1 and about 1.4 wt % Si, and the balance being Co;

wherein the total concentration of boron and carbon is between about 1.2 wt % and about 2.5 wt %; and

wherein the maximum Si concentration is calculated to be less than about (1.8−(0.12*[Mo])+(0.1*([B]+[C]))).

15 . The Co-based saw tip of claim 11 consisting essentially of about 29 wt % Cr, about 8.5 wt % Mo, 1.3 wt % W, about 1.3 wt % C, about 0.5 wt % B, from about 0 to about 10 wt % elements selected from the group consisting of Mn, Ni, and Fe, about 0.8 wt % Si, and the balance being Co.

16 . A method of applying a saw tip to a saw blade comprising:

melting a filler metal to form a weld pool that solidifies as the saw tip on the saw blade;

wherein the filler metal comprises by approximate weight %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

  0-1.57

Co

Balance;

wherein the total concentration of boron and carbon is between about 1.2 wt % and about 2.5 wt %;

wherein the Si has a concentration no greater than about (1.8−(0.12*[Mo])+(0.1*([B]+[C]))).

17 . The method of claim 16 wherein the filler metal is in the form of a tubular wire comprising a Co-based sheath and metal powder placed therein.

18 . The method of claim 16 wherein the filler metal consists essentially of, by approximate weight %:

C

0.3-2.4

B

0.1-1.0

Cr

25-35

Mo

 4-20

Si

 0.1-1.57

Mn + Ni + Fe

 0-10

W

1-4

Co

Balance.

19 . The method of claim 16 wherein the Si has a concentration between about 0.1 wt % and about 1.4 wt %.

20 . The method of claim 16 , wherein the filler metal consists essentially of about 1.2 wt % C, about 0.5 wt % B, about 29 wt % Cr, about 1.3 wt % W, about 8.5 wt % Mo, from about 0 to about 10 wt % elements selected from the group consisting of Mn, Ni, and Fe, less than about 1.4 wt % Si, and the balance being Co.