Table 6-1.—Corrosion-Resistant Steel Tubing Specification Tubing Material Type Condition General Usage and Applications MIL-T-7081 6061 A1 Specification covers annealed and three heat treated tempers used mostly in 0-annealed and T-6. Has good workability. The 6061-T6 is used in hydraulic/pneumatic 3000 psi systems. MIL-T-8506 304 Annealed Low-pressure applications such as fuel lines. 18-8 Unsatisfactory for high-pressure hydraulic lines. Corrosion-Resistant Has high degree of resistance to corrosion. Steel (CRES) MIL-T-8504 304 Annealed Unsatisfactory for welding, brazing or exposure 18-8 to temperatures higher than 800°F. Used in CRES high-pressure hydraulic/pneumatic systems. MIL-T-8606 304L Annealed Hydraulic/mechanical applications. Has high 18-8 (low carbon) resistance to corrosion and high temperatures up CRES 321 to 1500°F. Suitable for applications requiring 347 welding/brazing. Type II intended for high-pressure hydraulic applications, using brazed sleeve joints. MIL-T-6845 304 1/8H Used in high-pressure hydraulic/pneumatic 18-8 systems. Unsuitable for welding/brazing CRES applications or exposure to temperatures above 800°F. MIL-T-8973 304L 1/8H Used in high-pressure hydraulic/pneumatic 18-8 (low carbon) systems assembled with brazed sleeve joints. CRES 316L Suitable for use in moderately corrosive or (low carbon) oxidizing environments, temperatures to 1200°F. 321 Weldable. 347 MIL-T-5695 304 1/4H Used for aircraft structural parts or similar 18-8 1/2H applications not requiring sharp bends or flaring. CRES Unsatisfactory for welding other than resistance weld. MIL-T-8808 321 Annealed Aircraft hydraulic quality, used in high-pressure 18-8 347 hydraulic/pneumatic systems. Most often used in CRES these systems requiring brazing/welding. 6-2