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New technology of roll production

'laser clading' is a modern wcco (wolfram-carbide-cobalt) melting process that increases detail longevity. As a result, we have new roll production technology that increases roll work resources by 4-5 times.

A major problem faced by metallurgy companies working in the field of hot steel rolling, is the very short work longevity (measured by hours) of various expensive rolls. This is due to the extreme work conditions (where the temperature reaches 950 degrees Celsius). Additionally, there are constant cyclic percussive loadings and sudden water stream cooling. Many technical improvements have been made to increase roll longevity by optimising the chemical composition of roll material matching the technological process of thermo-technical treatment. However, it is clear that continuing in this way holds no future prospect since all possibilities have been exhausted. Ways could be discovered to increase longevity another 2 to 3 percent, but that does not suit current requirements. This problem could be resolved by utilising WC-Co (wolfram carbide-cobalt), a high-quality material. Such a mixture can be produced with the assistance of powder metallurgy. Produced details are inclined to crack; furthermore, they are very expensive. However, details are long lasting if they do not crack. The obvious way towards resolution of the problem is formation of a cover on the working surface of steel blank from special materials, which are suitable for work under existing conditions. Instead of using a monolithic mixture of WC-Co, a layer of WC-Co carbide is melted on the steel blank. To accomplish this by using the 'Laser Cladding' process, development of a sprinkling technology is needed, which would enable production of a WC-Co covering in a greater thickness. The covering can be formed from powders and combined with the steel blank by employing metallurgy relations. The project partner 'NEOMAT' in LATVIA has solid experience in the production of wolfram carbide-cobalt powders, as well as tremendous scientific and industrial potential. The company's working experience includes a new technological process for spheroidal powder production. 'TECHNOLOGIJA' is a company with thirteen years of experience in the formation of powder coverings that are wear-resistant. The company has mastered HVOF, plasma, flame gas, and other cover processes. The WC-Co covering formed by the HVOF (High Velocity Oxy Fuel) process is notable for especially high wear-resistance. However, the covering formed in this way is only practical for work under conditions in which temperature does not exceed 400 degrees Celsius and there are no percussive loadings. Nonetheless, the WC-Co material itself is beneficial. The appropriate technological process for melting the WC-Co covering must be selected. The 'Laser Cladding' process is well known in Western countries. It is a progressive process, allowing the melting of different materials with the help of laser by which there is a minimal thermal effect to the product itself. For example, while melting the sprayed material on the cover of a detail, the temperature reaches 3000-4000 degrees Celsius in the melting zone. Meanwhile, the heat only reaches a depth of 0.1 mm in the detail, and has no thermal effect on the detail. This process is automated and fully controlled. However, this process is still not used for resolving metallurgy industry problems. The purpose of the project is to utilise the 'Laser Cladding' process as a solution to the problem described. Keywords: roll, lasers, technology.
Acronym: 
ULCOP
Project ID: 
3 444
Start date: 
01-01-2005
Project Duration: 
32months
Project costs: 
400 000.00€
Technological Area: 
Forming (rolling, forging, pressing, drawing)
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.