TP304 304L 316 316L Exhaust Steel Tube.Video
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TP304 304L 316 316L Exhaust Steel Tube.Video
1. Material properties and core differences
| rade | Carbon Content | Alloying Elements | Corrosion Resistance | High-Temperature Performance | Typical Applications |
|---|---|---|---|---|---|
| TP304 | ≤0.08% | Cr18–20%, Ni8–10% | Resistant to atmospheric, water, and weak acid/alkali (general-purpose) | Service temperature ≤870°C; limited high-temperature oxidation resistance | Common automotive exhaust systems, industrial ventilation pipes |
| TP304L | ≤0.03% (ultra-low) | Same as TP304 (low-carbon) | Enhanced intergranular corrosion resistance after welding | Service temperature ≤870°C; stable performance post-welding | Exhaust structures requiring frequent welding (e.g., modified exhausts) |
| TP316 | ≤0.08% | Cr16–18%, Ni10–14%, Mo2–3% | Molybdenum-alloyed for enhanced chloride resistance (e.g., seawater, HCl) | Service temperature ≤870°C; superior high-temperature strength vs. 304 | Coastal exhaust systems, chemical waste gas pipelines |
| TP316L | ≤0.03% (ultra-low) | Same as TP316 (low-carbon) | Optimal chloride resistance and intergranular corrosion resistance after welding | Service temperature ≤870°C; excellent long-term high-temperature stability | Exhaust systems in high-corrosion environments (e.g., marine engineering, medical equipment) |
1. Production process
Welding process:
TIG welding: suitable for thin-walled pipes (wall thickness ≤ 3mm), argon gas protection is required (purity ≥ 99.99%).
MIG welding: high efficiency, but the weld needs to be polished (roughness Ra ≤ 12.5μm).
Surface treatment:
Pickling and passivation: use HNO₃+HF mixed liquid to remove oxide scale and form a passivation film (ASTM A967 standard).
Coating protection: ceramic coating (such as ZrO₂) can reduce thermal conductivity by 30% and temperature resistance up to 1200.
2. Implementation standards
International standards:
ASTM A312/A312M-24b: austenitic stainless steel seamless/welded pipe, suitable for high temperature and corrosive environment.
ASME SA-249: welded austenitic steel pipe for boilers and superheaters.
