Crack resistant hardfacing alloys
Embodiments of an alloy that can be resistant to cracking. In some embodiments, the alloy can be advantageous for use as a hardfacing alloys, in both a diluted and undiluted state. Certain microstructural, thermodynamic, and performance criteria can be met by embodiments of the alloys that may make them advantageous for hardfacing.
1. A hardfacing deposit, wherein the hardfacing deposit comprises:
Fe and about 0.68 wt. % to about 1.25 wt. % C; and
a matrix comprising at least 50% martensite by volume, a macro-hardness of 57 HRC or greater, and a high resistance to stress cracking and hot tearing when welded as a single layer or over a worn existing hardfacing layer;
wherein a minimum carbon level in the matrix is 0.6 wt. %;
wherein the hardfacing deposit contains greater than 0 volume % grain boundary carbides and/or borides and less than about 15% grain boundary carbides and/or borides; and
wherein the hardfacing deposit has high abrasion resistance as characterized by an ASTM G65A mass loss of less than 0.5 grams.
2. The hardfacing deposit of claim 1 , wherein the hardfacing deposit contains both carbide and boride precipitates when welded over a worn existing hardfacing layer.
3. The hardfacing deposit of claim 1 , wherein the hardfacing deposit comprises Fe and, in wt. %:
B: about 0.6 to about 0.9;
Cr: about 14.25 to about 26; and
Nb+Ti+V: about 3.5 to about 4.5.
4. The hardfacing deposit of claim 3 , wherein the hardfacing deposit further comprises, in wt. %:
Mn: about 1.1;
Mo: about 1; and
Si: about 0.5.
5. The hardfacing deposit of claim 1 , wherein the hardfacing deposit comprises Fe and, in wt. %:
B: 1;
C: 0.8;
Cr: 16; and
Nb: 3.5.
6. The hardfacing deposit of claim 5 , wherein the hardfacing deposit does not contain Mn, Mo, Si, Ti, V, W, or Zr.
7. The hardfacing deposit of claim 1 , wherein the matrix comprises at least 90% martensite by volume.
8. The hardfacing deposit of claim 1 , wherein a majority of a composition of the hardfacing deposit is Fe.
9. The hardfacing deposit of claim 1 , wherein the hardfacing deposit contains less than about 10% grain boundary carbides and/or borides.
10. The hardfacing deposit of claim 1 , wherein the hardfacing deposit contains less than about 5% grain boundary carbides and/or borides.
11. The hardfacing deposit of claim 1 , wherein the hardfacing deposit is formed from a wire.
12. The hardfacing deposit of claim 11 , wherein the wire comprises Fe and, in wt. %:
C: about 0.75 to about 1.25;
B: about 0.6 to about 0.9;
Cr: about 14.25 to about 26; and
Nb+Ti+V: about 3.5 to about 4.5.