1. Material Definition and Standard Specifications
A32128 is titanium-stabilized austenitic stainless steel pipe for aviation applications (corresponding to the US designation AMS 5524). Its core characteristics are:
Composition Design:
Chromium-nickel base (Cr 17.0-19.0%, Ni 9.0-12.0%) + titanium reinforcement (Ti ≥ 5 × C%, typically 0.30-0.60%);
Ultra-low carbon (C ≤ 0.08%), controlled phosphorus and sulfur limits (P ≤ 0.025%, S ≤ 0.010%);
Implementation Standards: AMS 5524 (Aerospace Material Specification), GB/T 33821 (National Aviation Standard). 2. Core Performance Advantages
Intergranular Corrosion Resistance: Passes ASTM A262 Practice E testing (nitric acid + fluoride environment);
High-Temperature Performance:
Continuous operating temperature 800°C (short-term 900°C);
Oxidation resistance superior to 304 stainless steel (oxidation weight gain at 800°C reduced by 25%);
Processing Characteristics:
Welding requires ER321 welding wire, followed by post-weld solution treatment (1010-1120°C rapid cooling).
3. Typical Aviation Applications
Engine Systems:
Fuel Line Support Rings;
Nozzle Insulation Brackets;
Fuselage Structures:
Fastener Bushings in High-Stress Areas;
Landing Gear Hydraulic Ducts. 4. Comparison with Similar Materials
vs. A32100 (conventional 321):
Higher purity ([O] ≤ 30 ppm, [N] ≤ 150 ppm);
20% improved fatigue life (R = 0.1, 10⁷ cycles);
vs. A286 (nickel-based alloy):
Cost is only 1/3, but high-temperature strength is slightly inferior.
5. Procurement and Processing Key Points
Key Testing:
Titanium content verification (Ti/C ≥ 5);
100% penetrant testing (PT) to detect surface defects;
