I. Standard system and naming logic

• SUS316L (Japanese Standard JIS G4303)

Ultra-low carbon austenitic stainless steel defined under the Japanese Industrial Standard System, the suffix “L” specifically refers to the carbon content of ≤ 0.030% of the low carbon version, suitable for welding after the need to maintain the corrosion resistance of the scene.

• TP316L (ASTM A312)

ASTM standard “TP” means Tube & Pipe (pipe), its chemical composition is similar but the maximum allowable carbon content is 0.035%, which is 16.7% wider than SUS316L. In the American Standard system need to be synchronized to meet the ASME SA-240 plate standard requirements

Ⅱ.Comparison of core performance differences

(i) Chemical composition control

Element	SUS316L Standard Values	TP316L Standard Values	The Impact Of Differences
C	≤0.030%	≤0.035%	Affect welding process
Mo	2.0-3.0%	2.0-3.0%	Pitting resistance core element ‌
Ni	10.0-14.0%	10.0-14.0%	Austenite stability assurance ‌

(ii) Physical performance

•  Tensile strength

Typical values are 485MPa for SUS316L and 485-620MPa for TP316L, with the latter having a higher upper strength limit but with a 30% increase in dispersion.

• Corrosion resistance

Intergranular corrosion: SUS316L through the GB/T4334.5 method of testing pass rate of 12% higher than TP316L

Pitting Corrosion Equivalent (PREN): both ≥ 28, but SUS316L due to more stringent carbon control so that the actual PREN value increased 1.2-1.5 units

Ⅲ. Application Scenario Selection Guide

(i) Preferred scenario for SUS316L

•  Biopharmaceutical clean piping

Requirements for ultra-low surface iron ion precipitation (≤ 0.1μg/cm²), SUS316L electrolytic polishing roughness Ra ≤ 0.3μm

• Ocean platform seawater system

In Cl-concentration ≥20000ppm environment, SUS316L service life is 20% longer than TP316L.

(ii) Preferred TP316L scenario

• Oil heat exchanger tube piping

American Standard system allows for a more economical cold-drawing process, with a cost reduction of 8-15 percent

•  Food machinery frame structure

AFSL has more flexible control of dimensional tolerances (e.g. OD tolerance ±1% vs. ±0.8% for Japanese standards)

IV Quality Assurance System

(i) Spectroscopic Inspection (PMI)

Full elemental analysis per batch to ensure Mo content ≥ 2.5% (corrosion resistance threshold)

(ii) Intergranular corrosion accelerated test

Adopting 65% nitric acid boiling method, 3 times more sensitive than conventional sulfuric acid-copper sulfate detection method

Concluding Remarks

By accurately analyzing the differences between SUS316L and TP316L (e.g., 53% improvement in carbon control accuracy) and the common advantages (PREN values exceed industry benchmarks).

Stratify customers accurately. Facing the Japanese and Korean customers to promote SUS316L, at the same time to provide JIS test report; facing the North American customers to TP316L, informing our company will be strictly in accordance with the United States General Certification ASME production production; and facing the Middle East customer intentions, the use of double standard certification models that meet the norms of stainless steel pipe EN/BS/ISO, etc.