Kształtowanie struktury kompozytów na osnowie stali szybkotnącej infiltrowanych miedzią

• Autorzy: Madej M. , Leżański J.

Warianty tytułu

EN

Engineering the structure of copper infiltrated high speed steel based composites

• Języki publikacji: PL

Abstrakty

PL

Przedstawiono badania wpływu technologii oraz dodatków stopowych na strukturę i wybrane własności kompozytów na osnowie stali infiltrowanej miedzią. Materiał badawczy stanowiły kształtki ze stali szybkotnącej z dodatkiem węglika wolframu, miedzi i grafitu, infiltrowane miedzią (metodą nakładkową). Przeprowadzone analizy struktury i własności wytworzonych kompozytów pozwoliły na określenie podstawowych zależności występujących w badanych materiałach.

EN

High hardness, mechanical strength, heat resistance and wear resistance of M3/2 high speed steel (HSS) make it an attractive material for manufacture of valve train components such as valve seat inserts and valve guides [2, 3]. Since technological and economical considerations are equally important, infiltration of high-speed steel skeleton with liquid cooper has proved to be a suitable technique whereby fully dense material is produced at low cost. Attempts have been made to describe the influence of the production process parameters and alloying additives, such as tungsten carbide, electrolytic cooper and graphite on the microstructure and mechanical properties of copper infiltrated HSS based composites. The compositions of powder mixtures are 100% M3/2, M3/2+30% WC, M3/2+7.5% Cu, M3/2+0.3% C (graphite). The powders were uniaxially cold compacted in a cylindrical die at 800 MPa. The green compacts were sintered in vacuum at 1150°C for 60 minutes. Thereby obtained porous skeletons were subsequently infiltrated with copper, by gravity method, in vacuum furnace at 1150°C for 15 minutes. The M3/2 grade HSS powder cannot be fully densified at a temperature as low as 1150°C and the as-sintered density is approximately equal to the green density [2, 4|. The same situation has been found with M3/2+7.5% Cu and M3/2 + 0.3% C materials. Addition of 30% tungsten carbide increases the as-sintered density presumably due to occurrence of liquid phase as a result of chemical reaction between the steel matrix and tungsten carbide particles. The properties of the investigated composites are given in Table 1. The morphologies of capillaries in porous and as-sintered materials as well as microstructures of the composites are shown in Figs 2-5. From the analysis of the obtained results (Tab. 1) and microstructural observations it may be concluded that the microstructure is mainly affected by the manufacturing route and powders characteristics (M3/2 HSS, tungsten carbide and electrolytic cooper). Scanning electron microscopy (SEM) shows that in the material containing 30% tungsten carbide, the carbide phase is evenly distributed within the cooper-rich regions. Additions of electrolytic cooper, of about 25%, has created a microstructure which consists of ,,paths" and ,,lakes" of copper due to melting of the cooper powder (Fig. 4b, d). Graphite does not essentially affect the microstructure. The differences in the capillary morphology between 100%M3/2 (Fig. 2c) and M3/2+0.3% C (Fig. 5c) materials, in as-sintered condition, have been found insignificant.

Słowa kluczowe

PL

kompozyty; struktura; infiltracja; infiltracja miedzią; badania

EN

composites; structure; infiltration; copper infiltrated; investigation

• Wydawca: Wydawnictwo Politechniki Częstochowskiej
• Czasopismo: Kompozyty
• Rocznik: 2001
• Tom: R. 1, nr 2
• Strony: 175--179
• Opis fizyczny: Bibliogr. 4 poz., tab., rys.

Twórcy

autor

Madej M.

• Akademia Górniczo-Hutnicza, Zakład Metaloznawstwa i Metalurgii Proszków, ul. Mickiewicza 30, 30-059 Kraków

autor

Leżański J.

• Akademia Górniczo-Hutnicza, Zakład Metaloznawstwa i Metalurgii Proszków, ul. Mickiewicza 30, 30-059 Kraków

Bibliografia

• [1] Leżański J., Inflirtracja cieczy w porowatych materiałach, Metalurgia i Odlewnictwo 1988,118.
• [2] Greetham G., Development and performance on infiltrated and non-infiltrated valve seat insert materials and their performance, Powder Metall. 1990, 3, 2, 112-114.
• [3] Wright C.S., The production and application of PM high speed steels, Powder Metall. 1994, 3, 937-944.
• [4] Igharo M., Wood J.V., Effect of consolidation parameters on properties of sintered high speed steels, Powder Metall. 1990, 33, 1, 70-76.