7. Welding of Aluminium Alloys kau.ac.kr（7所示。）.pdf

7. Welding of Aluminium Alloys 7. Welding of Aluminium Alloys 84 Figure 7.1 compares basic physical properties Property Al Fe of steel and aluminium. Side by side with dif- Atomic weight [g/Mol] 26.9 55.84 ferent mechanical behaviour, the following Specific weight [g/cm³] 2.7 7.87 Lattice fcc bcc differences are important for aluminium weld- E-module [N/mm²] 71*10³ 210*10³ ing: R PO,2 [N/mm²] ca. 10 ca. 100 pO,2 - considerably lower melting point compared R m [N/mm²] ca. 50 ca. 200 m spec. Heat capacity [J/(g*°C)] 0.88 0.53 with steel Melting point [°C] 660 1539 - three times higher heat conductivity Heat conductivity [W/(cm*K)] 2.3 0.75 Spec. el. Resistance [nm] 28-29 97 - considerably lower electrical resistance Expansion coeff. [1/°C] 24*10-6 12*10-6 - double expansion coefficient FeO - melting point of Al 0 considerably higher 2 3 Oxydes Al O Fe O 2 3 3 4