Thermal Expansion Coefficient and Mechanical Properties of Friction Stir Welded Invar (Fe-36%Ni)

• Published in: Journal of materials engineering and performance Vol. 18; no. 7; pp. 925 - 934
• Main Authors: Jasthi, Bharat K., Arbegast, William J., Howard, Stanley M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2009; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Corrosion and Coatings; Engineering Design; Ferrous alloys; Friction stir welding; Iron; Low expansion alloys; Materials Science; Parents; Quality Control; Reliability; Safety and Risk; Thermal expansion; Tribology; Wear; Welded joints; coefficient of thermal expansion; Invar; PCBN; friction stir welding; W-25%Re
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-008-9320-7

Two high-temperature pin tools, one a polycrystalline cubic BN and the other of W-25%Re, were used to friction stir weld 12.7 mm thick Invar (Fe-36%Ni) plate. Successful welds were produced at a rotational speed of 600 rev min −1 and travel speeds of 76, 102, and 127 mm min −1 . The coefficient of thermal expansion, tensile strength, and microhardness of the welds were measured and found to be essentially unchanged from the parent material. The measured elongation was 52% for the parent material and 30 and 37% for welds made with the W-Re and the polycrystalline cubic BN pin tools. Both pin tools produced comparable welds but the W-Re tool exhibited more wear and left small wear remnants in the weld especially at the weld plunge.