Components of track-type machines having a metallurgically bonded coating

Abstract

Undercarriage assembly components of track-type machines having a metallurgically bonded wear-resistant coating and methods for forming such coated undercarriage assembly components is taught herein. The bodies of the undercarriage assembly components, formed of an iron-based alloy, have a hard metal alloy slurry disposed on a surface or into an undercut or channel and then fused to form a metallurgical bond with the iron-based alloy. The wear-resistant coating comprises a fused, metal alloy comprising at least 60% iron, cobalt, nickel, or alloys thereof. The portion of the outer surface of the undercarriage assembly components having the wear-resistant coating corresponds to a wear surface of the component during operation of the endless track of the track-type vehicle.

1 - 9 . (canceled) 
     
     
         10 . A method of making a pin bushing joint, the method comprising:
 forming a bushing including an outer surface having an outer diameter and including an inner surface having an inner diameter;   forming a track pin including an outer surface substantially conforming to a portion of the inner surface of the bushing, wherein the inner surface of the bushing and the outer surface of the track pin form a wear surface;   removing portions of the wear surface from the inner surface of the bushing to expose an area of the bushing to be coated and removing portions of the wear surface from the outer surface of the track pin to expose an area of the track pin to be coated;   coating the exposed area of both the bushing and the track pin with a slurry comprising a fusible, hard metal alloy with at least 60% by weight of iron, cobalt, nickel or alloys thereof in the form of a finely divided powder, polyvinyl alcohol, a suspension agent and a deflocculant; and   forming a metallurgical bond between the exposed area and the coating slurry to form a wear-resistant coating.   
     
     
         11 . The method of  claim 10 , further comprising adjusting the thickness of the slurry so that the final wear-resistant coating is flush with adjacent unremoved areas of the bushing and the track pin. 
     
     
         12 . The method of  claim 10 , wherein the step of forming a metallurgical bond comprises drying the coated slurry, heating the coated body to a fusion temperature of the fusible, hard metal alloy in a controlled atmosphere of at least one inert gas or reducing atmosphere excluding nitrogen, and cooling the coated body to ambient temperature. 
     
     
         13 . The method of  claim 10 , wherein the bushing and the track pin are formed of a medium carbon steel. 
     
     
         14 . The method of  claim 10 , comprising removing portions of the outer surface of the bushing to expose a second area of the bushing to be coated;
 coating the exposed second area of the bushing with a slurry comprising a fusible, hard metal alloy with at least 60% by weight of iron, cobalt, nickel or alloys thereof in the form of a finely divided powder, polyvinyl alcohol, a suspension agent and a deflocculant; and   forming a second metallurgical bond between the exposed second area and the coating slurry to form a second wear-resistant coating.   
     
     
         15 . An undercarriage track chain bottom roller comprising:
 at least one cylindrical portion; and   at least one flange of greater diameter than said at least one cylindrical portion,   wherein at least a portion of said at least one cylindrical portion and said at least on flange portion being subjected to wear,   wherein said portions being subjected to wear having a metallurgically bonded, wear-resistant coating and   wherein said wear-resistant coating comprising a fused hard metal alloy comprising at least 60% by weight iron, cobalt, nickel or alloys thereof.   
     
     
         16 . The undercarriage track chain bottom roller of  claim 15 , wherein said at least one cylindrical portion and flange are formed of a hardened steel. 
     
     
         17 . The undercarriage track chain bottom roller of  claim 15 , wherein said roller has two flange portions, each flange portion having at least one portion subjected to wear, the portions of said flanges being subjected to wear having said metallurgically bonded, wear-resistant coating. 
     
     
         18 . The undercarriage track chain bottom roller of  claim 15 , wherein said roller is formed of two essentially identical portions each having a cylindrical portion and a flange portion which cylindrical portions are secured by welding to one another. 
     
     
         19 . The undercarriage track chain bottom roller of  claim 15 , wherein the outer surface of the said cylindrical and flange portions being subjected to wear are removed and replaced with the said wear-resistant coating. 
     
     
         20 . The undercarriage track chain bottom roller of  claim 15 , wherein the outer surface of the said wear-resistant coating is flush with the remaining outer surface of said cylindrical and flange portions. 
     
     
         21 . The undercarriage track chain bottom roller of  claim 15 , wherein the wear-resistant coating has a Vickers hardness greater than 950 HV. 
     
     
         22 . The undercarriage track chain bottom roller of  claim 15 , wherein the wear-resistant coating has a thickness of about 1.5 mm. 
     
     
         23 . A method of making an undercarriage track chain bottom roller, the method comprising:
 forming a roll body having at least one cylindrical portion and at least one flange portion;   removing the outer surface of those portions of the said cylindrical and flange portions subject to wear to expose an area of the roller body to be coated;   coating the exposed area with a slurry comprising a fusible, hard metal alloy with at least 60% by weight of iron, cobalt, nickel or alloys thereof in the form of a finely divided powder, polyvinyl alcohol, a suspension agent and a deflocculant; and   forming a metallurgical bond between the exposed area and the coating slurry to form a wear-resistant coating.   
     
     
         24 . The method of  claim 23 , further comprising adjusting the thickness of the slurry so that the final wear-resistant coating is flush with adjacent unremoved areas of the said cylindrical and flange portions. 
     
     
         25 . The method of  claim 23 , wherein the step of forming a metallurgical bond comprises drying the coated slurry, heating the coated body to a fusion temperature of the fusible, hard metal alloy in a controlled atmosphere of at least one inert gas or reducing atmosphere excluding nitrogen, and cooling the coated body to ambient temperature. 
     
     
         26 . The method of  claim 23 , wherein the said roller body is formed of a medium carbon steel. 
     
     
         27 . A track chain link of an endless track of a track-type machine, the track chain link comprising:
 a body formed of hardened steel;   a mounting surface on a first edge of the body, the mounting surface including at least one opening for an attachment device; and   a contact surface on a second edge of the body,   wherein the contact surface is opposite the mounting surface,   wherein the contact surface includes a substantially planar region extending a distance along the second edge forming a wear surface, and   wherein the wear surface has a metallurgically bonded, wear-resistant coating, the wear-resistant coating comprising a fused hard metal alloy comprising at least 60% by weight iron, cobalt, nickel or alloys thereof.   
     
     
         28 . The track chain link of  claim 27 , wherein the hardened steel is case carburized. 
     
     
         29 . The track chain link of  claim 27 , wherein the portion of the contact surface is removed and replaced with the wear-resistant coating. 
     
     
         30 . The track chain link of  claim 27 , wherein an outer surface of the wear-resistant coating is flush with the remaining portion of the contact surface. 
     
     
         31 . The track chain link of  claim 27 , wherein the wear-resistant coating has a Vickers hardness greater than 950 HV. 
     
     
         32 . The track chain link of  claim 27 , wherein the wear-resistant coating has a thickness of about 1.5 mm. 
     
     
         33 . A method of making a track chain link, the method comprising:
 forming the track chain link, the track chain link including a body, a mounting surface on a first edge of the body, and a contact surface on a second edge of the body, wherein the mounting surface includes at least one opening for an attachment device, the contact surface includes a substantially planar region extending a distance along the second edge forming a wear surface, and the contact surface is opposite the mounting surface;   removing portions of the wear surface to expose an area of the track chain link to be coated;   coating the exposed area of the track chain link with a slurry comprising a fusible, hard metal alloy with at least 60% by weight of iron, cobalt, nickel or alloys thereof in the form of a finely divided powder, polyvinyl alcohol, a suspension agent and a deflocculant; and   forming a metallurgical bond between the exposed area and the coating slurry to form a wear-resistant coating.   
     
     
         34 . The method of  claim 33 , further comprising adjusting the thickness of the slurry so that the final wear-resistant coating is flush with adjacent unremoved areas of the contact surface. 
     
     
         35 . The method of  claim 33 , wherein the step of forming a metallurgical bond comprises drying the coated slurry, heating the coated body to a fusion temperature of the fusible, hard metal alloy in a controlled atmosphere of at least one inert gas or reducing atmosphere excluding nitrogen, and cooling the coated body to ambient temperature. 
     
     
         36 . The method of  claim 33 , wherein the body is formed of hardened steel 
     
     
         37 . The method of  claim 33 , wherein the body is formed of a medium carbon steel. 
     
     
         38 . The method of  claim 33 , further comprising hardening the coated track chain link by quenching and tempering. 
     
     
         39 . The method of  claim 33 , further comprising hardening a portion of the body below the wear resistant coating by induction hardening, wherein a hardness of the hardened portion is HRC 50 to 55.