Chromium free hardfacing materials

a technology of hardfacing materials and chromium dust, which is applied in the direction of coatings, metallic material coating processes, molten spray coatings, etc., can solve the problems of chromium dust being known to cause cancer and undesirable for thermal spray applications, and achieve accurate measurement and measurement

Inactive Publication Date: 2016-01-28
SCOPERTA INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012]In some embodiments, the coating can be non-magnetic and therefore the coating thickness can be accurately measured with an Elcometer™ thickness gauge or similar device. In some embodiments, the coating can be non-magnetic and therefore the coating thickness can be accurately measured with an Elcometer™ thickness gauge or similar device after it has been exposed to temperatures exceeding about 1100 K for 2 hours or more and then slow cooled at a rate of 10K / s or less.
[0018]In some embodiments, the coating can be non-magnetic and therefore the coating thickness can be accurately measured with an Elcometer™ thickness gauge or similar device. In some embodiments, the coating can be non-magnetic and therefore the coating thickness can be accurately measured with an Elcometer™ thickness gauge or similar device after it has been exposed to temperatures exceeding about 1100 K for 2 hours or more and then slow cooled at a rate of 10K / s or less.
[0022]In some embodiments, the coating can be non-magnetic and the coating thickness can be accurately measured with an Elcometer™ thickness gauge or similar device after it has been exposed to temperatures exceeding about 1100 K for 2 hours or more and then slow cooled at a rate of 10K / s or less.

Problems solved by technology

However, chromium is considered undesirable for use in thermal spray applications due to the potential to form hexavalent chromium dust.
Hexavalent chromium dust is known to cause cancer.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0100]The previously disclosed alloy #4, Fe: BAL, Mn: about 5, Mo: about 13, Si: about 10 was produced in the form of a 40 gram trial ingot to verify hardness and thermal spray vitrification potential. The ingot hardness was measured to be 534 Vickers (converting from a Rockwell C measurement). The microstructure of the ingot showed a fully eutectic structure indicating a strong possibility for amorphous or nanocrystalline structure under the rapid cooling rate of the spray process. This material has been selected for manufacture into 1 / 16″ cored thermal spray wire for twin wire arc spray trials after slight modification to the alloy #14, Fe: BAL, Mn: about 5, Mo: about 13, Si: about 10, Al: about 2.

example 2

[0101]The previously presented alloy #5, Fe: BAL, Mn: about 5, Mo: about 7, Si: about 10 was produced in the form of a 40 gram trial ingot to verify hardness and thermal spray vitrification potential. The ingot hardness was measured to be 534 Vickers (converting from a Rockwell C measurement). The microstructure of the ingot showed a fully eutectic structure indicating a strong possibility for amorphous or nanocrystalline structure under the rapid cooling rate of the spray process. This material has been selected for manufacture into 1 / 16″ cored thermal spray wire for twin wire arc spray trials after slight modification to alloy #15, Fe: BAL, Mn: about 5, Mo: about 7, Si: about 10, Al: about 2.

example 3

[0102]The previously disclosed alloy #8, Fe: BAL, C: about 0.25, Mn: about 19, Mo: about 7, Si: about 5 was produced in the form of a 40 gram ingot to verify hardness, thermal spray vetrification potential and magnetic permeability. In this example, the alloy candidate is being developed as a ‘readable’ coating which requires the alloy to be non-magnetic in the sprayed form. The ingot hardness was measured to be 300 Vickers (converting from a Rockwell C measurement). While this is below the desired hardness threshold, it is well known by those skilled in the art that the rapid cooling process achieved in thermal spray will increase the hardness of the alloy in this form. Thus, it is not unreasonable to expect an increase in hardness in the sprayed form up to the desired level of 400 Vickers. The relative magnetic permeability was measured via a Low-Mu Magnetic Permeability Tester and was determined to be less than 1.01, well below the threshold required to ensure ‘readability’.

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Abstract

Disclosed are embodiments of Fe-based alloys for use as a hardfacing material having high hardness while avoiding the use of chromium. The alloys can be twin arc or thermally sprayed as coatings on different types of equipment. In some embodiments, the alloys can be readable even after heating of the alloys.

Description

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS[0001]Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57.BACKGROUND[0002]1. Field[0003]The disclosure generally relates to hardfacing materials which can be deposited as hardfacing coatings without the production of Cr, such as hexavalent Cr dust.[0004]2. Description of the Related Art[0005]Thermal spray processing is a technique which can be utilized to deposit a hard wear resistant and / or corrosion resistant layer onto the surface of a component. Thermal spray inherently creates a significant amount of dust due to the fact that about 10-40% or more of the feedstock material does not stick to the component of interest and rebounds of the surface in the form a fine metallic dust. One particular class of thermal spray materials which is used to form wear resistant layers is ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C22C45/02C22C38/12C22C38/08C22C38/04C22C38/02C23C4/06C22C38/58C22C38/50C22C38/48C22C38/46C22C38/44C23C4/12C22C38/14C22C38/00
CPCC22C45/02C22C38/14C22C38/12C22C38/08C22C38/04C22C38/02C22C38/004C22C38/002C22C38/58C22C38/50C22C38/48C22C38/46C22C38/44C23C4/125C23C4/06C23C4/067C23C4/131
Inventor CHENEY, JUSTIN LEEJIANG, TIANHO
Owner SCOPERTA INC
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