Sökning: "powder metallurgy PM"

Visar resultat 11 - 15 av 29 avhandlingar innehållade orden powder metallurgy PM.

1. 11. Influence of Segregants on Creep Fracture in Powder Metallurgical Martensitic Stainless Steel

   Författare :Mats Norell; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; AES; creep; segregants; powder metallurgy; prior particle boundaries; atomisation; SIMS; martensitic stainless steel; ESCA; cavities; powder surfaces;

   Sammanfattning : This thesis deals with the behaviour of segregants in Powder Metallurgical (PM) 10%Cr steel and their impact on creep fracture. Particular interest is taken in determining the reaction products involved in creep cavitation and how these are connected to the powder surface reactions during the gas atomisation and consolidation (hot isostatic pressing). LÄS MER

3. 12. Sintering of water-atomized iron and low-alloyed steel powder

   Författare :Johan Wendel; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reduction kinetics; water-atomized steel powder; water-atomized iron powder; sintering; oxide reduction; surface analysis; dilatometry; surface chemistry; thermogravimetric analysis;

   Sammanfattning : Iron and steel powder grades are extensively used in the powder metallurgy (PM) industry for manufacturing of ferrous structural components, with a major customer in the automotive industry. The powder grades are predominantly manufactured by water-atomization, yielding powder particles with highly irregular morphology and good compressibility, making the powder ideal for the conventional press-and-sinter manufacturing route. LÄS MER

4. 13. Contact fatigue and crack propagation studies of sintered PM steel

   Författare :Anders Holmberg; Åsa Kassman Rudolphi; Urban Wiklund; Johan Ahlström; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tribology; PM steel; Fatigue; Crack Initiation; Crack Propagation; Material Analysis; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

   Sammanfattning : Gears made of PM steel are of interest for the automotive industry because from the press/sinter route, complex geometries can be produced to near net shape with only a few processing steps while keeping the material and energy usage at a minimum. However, the PM steels of today have significant performance limitations caused by the inherent porosity which impairs the mechanical properties by acting as stress raisers in the material. LÄS MER

5. 14. Critical Aspects of Delubrication and Sintering of Chromium-alloyed Powder Metallurgy Steels

   Författare :Seshendra Karamchedu; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; delubrication; oxide reduction; surface oxide; carbon control; sintering atmosphere; chromium-alloyed sintered steels;

   Sammanfattning : The cost efficiency and performance of Powder Metallurgy (PM) steels can be improved by replacing conventionally used alloying elements such as copper and nickel with chromium. Utilizing chromium imposes a challenge in terms of processing due to its effect on powder compressibility and high oxygen affinity, the latter of which, to a certain extent, is dealt with by introducing chromium in prealloyed form that decreases its activity. LÄS MER

7. 15. Surface Characterization of Soft Magnetic Composite Powder and Compacts

   Författare :Christos Oikonomou; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; X-ray photoelectron spectroscopy XPS ; energy dispersive X-ray spectroscopy EDX ; surface layers; thickness determination; powder metallurgy PM ; soft magnetic composites SMC ; focused ion beam FIB ; depth profiling; high resolution scanning electron microscopy HR SEM ;

   Sammanfattning : .... LÄS MER