|Broad Area of Technology:||Materials Science and Engineering, Composite Materials|
|Narrow Field:||Thermal and Thermochemical Treatment, Hardening of Tools|
|Purpose:||The process permits increasing the performance, service characteristics and life of tools and machine parts made of steels, cast irons and hard alloys|
Brief Description and Specific Features
The process involves diffusion treatment of tools and machine parts (in a way similar to pack carburization) in metal oxide powder media during 4-6 h at the temperatures not exceeding 1000 °C (the chemical composition of the media and the temperature constitute the "know-how"). The treatment results in the formation of a uniform multicomponent carbide coating on the surface of the items. The thickness of the coatings is 4 - 7 mm on hard alloys, up to 70 mm on steels and up to 140 mm on cast iron; the microhardness is HV 2800 - 3700, which is close to that of silicon carbide. With the addition of a carburizing agent, the powder media permit obtaining coatings of a desired thickness on tool steels. The structure of the coatings is composed of globular alloyed carbides, the surface hardness being HRC 65 - 70.
Advantages Over Known Methods of Surface Hardening
the process is more simple and economical due to the use of standard equipment, cheap metal oxide media which allow multiple usage, and relatively low temperature
it does not require thorough cleaning of the surface
due to high thickness of the obtained coatings, the process allows for the subsequent sizing of the articles made from steels and cast irons
the technology is most efficient for disposable (not subjected to resharpening) hard alloy tools. For example, 1 kg of the powder medium (the cost is $20 - 30) used twice permits to process 1 - 2 kg of hard alloy tools (the cost is $100 - 300 per kg) increasing the wear resistance by the factor of 3 to 4, the strength of the material being unaffected. Moreover, sintering of the hard alloy may be combined with the diffusion treatment in the powder media.
Results of Testing in Industry
The use of multicomponent carbide coating produced by the developed process gives an opportunity to increase the service life of hard alloy cutting tools by the factor of 2 to 20 and the life of steel tools and machine parts by the factor of 2 to 5.
Examples: the increase of service life of processed tools, times:
For more information please contact the author:
Belarussia State Polytechnic Academy
65 F.Skorina Ave., built. 7
Phone: (375) 17 2581066 (home), 2399260 (office)
Fax: (275) 17 2329137
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