Metal Science and Heat Treatment Vol. 38. Nos. 5 - 6. 1996 UDC 621.78.063.4 QUENCHING MEDIA BASED ON POLYALKYLENE GLYCOL FOR HEAT TREATMENT OF ALUMINUM ALLOYS A. V. Sverdlin, t G. E. Totten, 2 and G. M. Webster 2 Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 17 - 19, June, 1996. Quenching media based on polyalkylene glycol have been used for heat treatment of aluminum alloys instead of hot water for .,0 years. However, their use ,till accompanied by some difficulties. In the aircraft industry of the U.S. aqueous solutions of polymers based on polyalkylene glycol are called quenching liquids of types I and II. The aim of the present work is to consider the possibility of using these media for quenching aluminum alloys. It is known from practice that the use of quenching media based on polyalkylene glycol instead of hot water can de- crease stresses in parts. However, a certain limitation on their use is caused by the fact that some properties of heat- treated parts are below the requisite level. The present work concerns the possibility of using quenching medium I based on polyal- kylene glycol for heat treatment of aluminum alloys in the aircraft and space industries. We conducted a detailed analysis of quenching medium A of a type I (UCON Quenchant), on which ample experi- mental material has been accumulated in industry. The characteristics of quenching medium A of type l (in accordance with ASM 3025) are as follows: 45 -48% H20, specific weight (20°C)), = I.I + 0.005 g/cm 3, refractive in- dex (20°C) 1"1=1,4145+0.0005, viscosity (at 100°C) v = (540 + 65) ~ I 0 - 5 m2/sec. Table I presents recommendations on the composition of the quenching medium of type I for some semifinished prod- ucts made of aluminum alloys. Table 2 presents the minimum admissible properties of aluminum alloys used in the aerospace industry in accordance with the standard [3]. Comprehensive investigations of the Bradley University, Peon& Illinois Umon Carbide Corporahon, Tarrytown, New York TABLE I Polymer Alloy Semifinished product Thickness, mm concentration, % 2024-T62 Sheet 20 16 7075-T6 25 4 20 - 22 7075-T73 Stamped preform 63 6 I0- 12 7075 76 5 20 - 22 poss;bility of using UCON Quenehant A quenching liquid for hardening massive forgings made of alloy 7075-T73 have been conducted by T. O. Anderson and M. D. Schuler (Hughes Aircraft Company). The design of the experiment is presented in Table 3, and the quenching method with mixing is presented in Fig. I. It can be seen from the data of Table 4 and Fig. 2 that the lowest strength characteristics are exhib- ited by forgings of alloy 7075-T73 with a cross section 100 mm in size. Their values depend on the concentration of the polymer, namely, Gb and o 02 decrease with its growth. On the basis of the data presented in Table 4 optimum concentra- tions of UCON Quenchant A are suggested for forgings of aluminum alloy 7075-T73, namely, Forging thickness, mm Polymer concentration, % 25 ............................ 25 50 ............................ 15 75 ............................ 15 I00 .............................. 10 TABLE 2 rain mln Cross-section o0 2 or Alloy size, mm N/mm 2 0.50-63 325 415 2024-T6 I 6 - 6.3 340 430 6.3- 127 340 430 6.30- 12.7 435 500 < 76.0 385 455 7075-T73 75- 100 380 440 100- 125 365 430 7075-T6 19 - 25 450 515 7050 50- 75 450 510 252 0026-0673/9610506-0252515 O0 ID 1997 Plenum Pubhshmg Corporation