AU2016102005A4

AU2016102005A4 - Method of Application of Hard Facing to Wear Parts and Apparatus formed therefrom

Info

Publication number: AU2016102005A4
Application number: AU2016102005A
Authority: AU
Inventors: Douglas Paul
Original assignee: Muddies Holdings Pty Ltd
Current assignee: Muddie's Holdings Pty Ltd
Priority date: 2016-11-18
Filing date: 2016-11-18
Publication date: 2016-12-15
Anticipated expiration: 2024-11-18
Also published as: WO2018090098A1

Abstract

A method of application of hard facing to wear parts, the method including the steps of providing at least one anchor portion on a wear part and attaching hard facing to the wear part using at least the at least one anchor portion.

Description

METHOD OF APPLICATION OF HARD FACING TO WEAR PARTS AND APPARATUS FORMED THEREFROM

TECHNICAL FIELD

[0001] The present invention relates to a method of application of hard facing to wear parts and apparatus formed using that method.

BACKGROUND ART

[0002] According to Wikipedia, hardfacing is a metalworking process where harder or tougher material is applied to a base metal. It is welded to the base material, and generally takes the form of specialized electrodes for arc welding or filler rod for oxyacetylene and TIG welding. Powder metal alloys are used in (PTA) also called Powder plasma welding system and Thermal spray processes like HVOF, Plasma spray, Spray and Fuse, etc.

[0003] Hardfacing may be applied to a new part during production to increase its wear resistance, or it may be used to restore a wom-down surface. Hardfacing by arc welding is a surfacing operation to extend the service life of industrial components, pre-emptively on new components, or as part of a maintenance program.[l] The result of significant savings in machine down time and production costs has meant that this process has been adopted across many industries such as Steel, Cement, Mining, Petrochemical, Power, Sugar cane and Food.

According to the results of an experimental study, the SMAW (Shielded Metal Arc Welding) and the GMAW (Gas Metal Arc Welding) hardfacing processes were effective in reducing the wear on the mouldboard ploughshare. With the SMAW and GMAW hardfacing processes, the life span of the ploughshare was increased approximately 2 times.

[0004] Extensive work in research has resulted in the development of a wide range of alloys and welding procedures. The optimum alloy selection is made considering the component service conditions and feedback of the service performance.

[0005] For each industrial application and wear phenomena, there is a welding electrode to provide wear resistance.

[0006] Hardfacing can be deposited by various welding and bonding methods: • Shielded Metal Arc Welding (SMAW) • Gas Metal Arc Welding (GMAW), including both gas-shielded and open arc welding • Oxyfuel Welding (OFW) • Submerged Arc Welding (SAW) • Electroslag Welding (ESW) • Plasma Transferred Arc Welding (PTAW), also called Powder Plasma welding system • Thermal spraying • Cold polymer compounds • Laser Cladding • Hardpaint [0007] Commonly applied materials include cobalt-based alloys (such as stellite), nickel-based alloys, chromium carbide alloys and NOREM. Hardfacing is sometimes followed by hot stamping to refinish the part or add colour or instructional information to the part. Foils or films can be used for a metallic look or other protection [0008] Although The common hardfacing problems are: • dilution, • spalling, • stress failure, • underbead cracking and • distortion.

[0009] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

[0010] The present invention is directed to a method of application of hard facing to wear parts and apparatus formed therefrom, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0011] With the foregoing in view, the present invention in one form, resides broadly in a method of application of hard facing to wear parts, the method including the steps of providing at least one anchor portion on a wear part /or a hardfacing member and attaching hard facing to the wear part using at least one anchor portion.

[0012] The wear part to which the hard facing is applied according to the present invention may be any type of wear part. Typically, a wear part has one or more wear surfaces and a hard facing will normally be provided relative to one or more of the wear surfaces. In particular, the hard facing will typically be applied to at least one, and normally more than one portion of the wear part but perhaps not everywhere surface which is present on a wear part.

[0013] Due to the wide variety wear parts which are available, the respective wear surfaces vary greatly in size and shape. The hard facing of the present invention can be applied to any one or more surfaces, in any size and/or shape and the hard facing may be applied to any portion of a wear surface. Normally, the hard facing is applied to the entirety or partially of at least one of the wear surfaces present on a wear part. Often, the position and extent of the hard facing applied to a wear surface and to which wear surfaces, will be based on the wear pattern of the particular wear part.

[0014] The hard facing of the present invention may be applied using any process or methodology provided that the process or methodology used allows anchoring of the hard facing to the at least one anchoring portion. Examples of processes to apply the hardfacing include weld, molten bonding or cold bonding techniques [0015] The hard facing applied may be or include any hard facing material or combination of materials. Typically hard facing is a metal material but other materials such as ceramics, tungsten carbide pressed forms/granules or similar could be used.

[0016] Metal(s) used for hard facing typically includes a substrate which may include one or more hard facing materials and/or particular material. Possible materials which could find use in the present invention include tungsten carbide, chromium carbide, martensitic stainless steel, austenitic manganese steels, semi-austenitic steels, austenitic stainless steel, cast iron (ADI,CADI low and CADI High), heat treatable steel and/or copper alloys. The particular type of hard facing provided will generally be chosen according to the particular wear part to which the hard facing is to be applied in the application for which the wear part is intended to be used.

[0017] In one particularly preferred embodiment, the hard facing is provided as a shaped block or similar preferably planar member which is mounted relative to the wear part.

Preferably, the hard facing member will be provided with an extension, preferably approximately centrally from a rear portion of the member which is preferably located at least partially within a preferred opening formed in the wear part. The extension can be any length but will preferably seat securely within the opening or relief preferably in a clearance fit.

[0018] In an alternative configuration the hardfacing block may be provided as a planar block with one or more extensions extending from one or more side edges to allow the block to be fitted around a portion of the sear part relative to the wear surface.

[0019] In a particularly preferred embodiment, an adhesive can be used to attach the hard facing block to the wear part. In particular, a portion of adhesive may be used within the opening and on a rear face of the hard facing member whereupon the extension of the hard facing member is located with the opening and hard facing member forced rearwardly onto the wear part.

[0020] The hard facing block may be provided on or into a recessed portion of the wear part in order to provide further security as to the location attachment of the hard facing block. The recess portion and/or preferred opening may be formed as a retrofit or at an original equipment manufacturing level. Using a technique such as this means that weakening of the substrate material of the wear part which can occur during conventional techniques of attaching hard facing relative to a wear part which all involve heating the substrate material, is avoided which means that if the hard facing block of the present invention is lost or worn away, the substrate material of the wear part exposed is still at its full strength rather than at a depleted strength which occurs in the prior art applications of hard facing.

[0021] The wear part will normally be provided with at least one anchor portion. The anchor portion may be provided at an original equipment manufacturing level or alternatively, the anchor portion may be provided as a part of new or replacement hardfacing.

[0022] Typically, at least one anchor portion will be provided relative to a wear surface relative to which hardfacing is to be applied. The particular nature of and number of anchor portion is provided will normally be dependent upon the particular configuration of the wear part and further, of the wear surface. For example, more than one anchor portion may be provided for larger wear surfaces and single leg portions may be provided for small wear surfaces.

[0023] Each anchor portion will preferably be or include at least one opening. The at least one opening will normally be provided at an angle relative to the wear surface. The angle will preferably be approximately 90° relative to the wear surface but, the angle may differ depending upon the particular wear part. For example, if the wear part is a rotating wear part, this may subject the particular wear surfaces to wear at slightly differing angles and therefore, the anchor portion may be provided approximately perpendicularly to the angle of the wear surface during the rotation.

[0024] According to the method of the present invention, one or more hardfacing elements is preferably provided relative to the at least one anchor portion. The hardfacing is normally deposited relative to a wear surface with a portion of the hardfacing located relative to the at least one anchor portion and according to the preferred embodiment, at least partially within the at least one opening.

[0025] According to a particularly preferred embodiment of the present invention, the hard facing will be applied as a weld, similar molten material or preformed tungsten carbide which then subsequently hardens or can be attached as a preformed shape to form the hard facing with a portion of the weld, molten material or preformed tungsten carbide deposited at least partially within the preferred opening and then extending outwardly onto at least a portion of the wear surface to function as hard facing or bonding agent for the wear surface. Any pattern or configuration of hard facing can be used provided that the hard facing is applied at least partially to the anchor portion.

[0026] Alternatively, the hard facing may be applied as a unitary plate or other type of member which is effectively welded or attached to the wear part using a weld, molten material or cold bonding agent deposited at least partially within the preferred opening and attaching the unitary plate or other type of member of hard facing material relative to the wear surface.

[0027] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0028] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

[0029] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows: [0030] Figure 1 is a front isometric view of a sizing segment with hard facing applied to selected teeth according to a preferred embodiment of the present invention.

[0031] Figure 2 is a top view of the sizing segment illustrated in Figure 1.

[0032] Figure 3 is a side elevation view of the sizing segment illustrated in Figure 1.

[0033] Figure 4 is a detailed review of the portion illustrated in Figure 1 identified as “A”.

[0034] Figure 5 is a front isometric view of an alternate sizing segment showing the location of the anchor portion.

[0035] Figure 6 is an isometric view of the sizing segment illustrated in Figure 1 after approximately 8 weeks use.

DESCRIPTION OF EMBODIMENTS

[0036] According to a particularly preferred embodiment of the present invention, a method of application of hard facing to wear parts is provided.

[0037] The method of application of hard facing to wear part according to the preferred embodiment includes the steps of providing at least one anchor portion on a wear part and attaching hard facing to the wear part using at least one anchor portion.

[0038] The wear part to which the hard facing is applied according to the present invention may be any type of wear part although the preferred embodiment illustrated in the accompanying Figures, is a sizing segment 100 for a roll crushing machine which crushes material using pressure and shear forces generated at low circumferential speed but at a high torque. Find material passes through the rolls without being crushed, falling through the gap between a pair of counter-rotating crushing rolls. The crushing rolls down to the number of exchangeable crushing segments which allow quick and easy exchange of the crushing segments was worn. The crushing segments have particular tooth configurations which allowed the crushing rolls to both crush the material and size the material.

[0039] As illustrated, the sizing segment 10 has an arcuate body 11 with a number of shaped keys 12 in order to slidingly engage with a corresponding configuration of keyways provided on an external surface of a crushing roll. The sizing segment 10 has a number of teeth upstanding from an external surface of the arcuate body 11 and in the illustrated embodiment, the teeth are either a low profile tooth 13 or an enlarged tooth 14. The teeth are provided in two substantially parallel, spaced apart rows on the body 11 and the enlarged teeth 14 are offset in the adjacent rows.

[0040] In this configuration, the sizing segment (a wear part) has a number of wear surfaces and hard facing is provided relative to the wear surfaces provided on the enlarged teeth 14, as illustrated in Figure 4, to an upper portion of the enlarged teeth 14 which extends above the level of the low profile teeth 13.

[0041] The hard facing of the present invention may be applied using any process or methodology provided that the process or methodology used allows anchoring of the hard facing to the at least one anchoring portion.

[0042] The hard facing applied may be or include any hard facing material or combination of materials. Typically hard facing is a metal material but other materials such as ceramics or similar could be used.

[0043] The wear part is provided with at least one anchor portion. The anchor portion may be provided at an original equipment manufacturing level or alternatively, the anchor portion may be provided as a part of new or replacement hardfacing.

[0044] The anchor portion is provided relative to a wear surface relative to which hardfacing is to be applied. In the illustrated embodiment, each anchor portion is an opening 15. As illustrated in Figure 5 in relation to an alternative configuration of segment, the opening 15 is provided at approximately 90° relative to the wear surface but, the angle may differ depending upon the particular wear part. For example, if the wear part is a rotating wear part, this may subject the particular wear surfaces to wear at slightly differing angles and therefore, the opening 15 may be provided approximately perpendicularly to the angle of the wear surface during the rotation.

[0045] According to the method of the present invention, one or more hardfacing elements is provided relative to the at least one anchor portion. The hardfacing is normally deposited relative to the wear surface with a portion of the hardfacing located relative to the at least one anchor portion and according to the preferred embodiment, at least partially within the at least one opening.

[0046] According to the particularly preferred embodiment of the present invention illustrated, the hard facing is applied as a unitary hardfacing plate 16 or cylindrical plug located in opening 15 which is effectively welded or attached to the wear part using a weld, molten material or cold bonding agent such as an adhesive or epoxy deposited at least partially or fully within the opening 15. The opening may be used to house at least a part of or contain a cylindrical hardfacing plug or disc which is formed integrally with, attached to or mounts a unitary hardfacing plate 16 or can be left in a cylindrical form relative to the wear surface.

[0047] Utilising the method of the present invention, the sizing segment of the illustrated embodiment can withstand the wear of use much more robustly than the carbon steel of the segment itself as evidenced by the illustration in Figure 6 which shows the sizing segment 10 after approximately 8 weeks use and in which the enlarged tooth 14 shows little wear and no loss of the unitary hardfacing plate 16 compared to the low profile teeth 13 which show significant wear.

[0048] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0049] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0050] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims

1. A method of application of hard facing to wear parts, the method including the steps of providing at least one anchor portion on a wear part and/or a hardfacing member and attaching hard facing to the wear part using at least the at least one anchor portion.

2. A method of application of hard facing to wear parts as claimed in claim 1 wherein each anchor portion is or includes at least one opening.

3. A method of application of hard facing to wear parts as claimed in claim 2 wherein the hardfacing is deposited relative to a wear surface with a portion of the hardfacing located at least partially within the at least one opening.

4. A method of application of hard facing to wear parts as claimed in claim 2 or claim 3 wherein the hard facing is applied as a weld or similar molten material which then subsequently hardens to form the hard facing with a portion of the weld or molten material deposited at least partially within the at least one opening and then extending outwardly onto at least a portion of the wear surface to function as hard facing for the wear surface.

5. A method of application of hard facing to wear parts as claimed in claim 2 or claim 3 wherein the hard facing is applied as a unitary plate which is welded or attached to the wear part using a weld or molten material deposited at least partially within the at least one opening and attaching the unitary plate or other type of member of hard facing material relative to the wear surface.