UNS S31653|1.4429|TP316LN Seamless Stainless Steel Pipe

Seamless Stainless Steel TP316LN Pipes (UNS S31653 / W.Nr. 1.4429) are nitrogen-strengthened, ultra-low carbon austenitic solutions engineered for superior mechanical strength and exceptional corrosion resistance. As a premier manufacturer based in Wenzhou, China, XinZhe produces high-integrity seamless piping that strictly adheres to ASTM A312, ASTM A213, and ASME SA312 international standards.

Distinguished by the strategic addition of Nitrogen (0.10–0.16%), our TP316LN piping offers significantly higher yield strength than standard 316L while maintaining excellent ductility and non-magnetic characteristics even after cold working. These pipes are indispensable for mission-critical applications in high-pressure chemical reactors, nuclear engineering, and cryogenic processing. Through advanced cold-drawing and precise solution annealing, XinZhe ensures every pipe maintains a stable austenitic microstructure and optimized resistance to sensitization and pitting.

“TP316LN offers a minimum yield strength of 205 MPa, which is higher than the 170 MPa of standard TP316L.”

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What Is TP316LN Seamless Pipe?

Seamless Stainless Steel TP316LN Pipe (UNS S31653 / 1.4406 / 1.4429)

Nitrogen-Enhanced Austenitic Stainless Steel for High-Pressure & Cryogenic Applications

Product Overview

1. What is TP316LN Stainless Steel Seamless Pipe?

SeamlessTP316LN stainless steel pipe (UNS S31653 / W.Nr. 1.4406 / 1.4429) is a nitrogen-strengthened, ultra-low carbon austenitic stainless steel designed for high-stress, corrosive, and cryogenic environments.

Manufactured through a seamless process (hot piercing + precision cold drawing), it ensures:

No weld seams or weak points
Uniform microstructure
Superior pressure resistance
Excellent corrosion performance

The“LN” designationindicates:

Additional Information

L (Low Carbon ≤0.03%) → Prevents intergranular corrosion and sensitization
N (Nitrogen 0.10–0.16%) → Enhances strength and corrosion resistance

Compared with standard 316L, TP316LN offers significantly higher mechanical strength and improved corrosion resistance, making it ideal for critical engineering applications.

2. Key Features & Technical Advantages

Higher Strength & Reduced Weight

Nitrogen addition increases:

Yield strength
Tensile strength
Design stress capability

Enablesthinner wall pipes, reducing material and system costs.

Superior Corrosion Resistance (High PREN)

The combination of Molybdenum + Nitrogenimproves:

Pitting resistance
Crevice corrosion resistance
Performance in chloride-rich environments

Excellent Resistance to Intergranular Corrosion

Ultra-low carbon content ensures:

No chromium carbide precipitation
Stability in welding heat-affected zones
Compliance with sensitization-resistant design

Outstanding Cryogenic Performance

TP316LN maintains:

High toughness at -196°C (LNG temperature)
Stable mechanical properties at low temperatures

Widely used in LNG, aerospace, and cryogenic storage systems

High Pressure Integrity

Manufactured in accordance with:

ASTM A312
EN 10216-5

Ensures safe operation in high-pressure fluid transport systems

To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for 316LN stainless steel.

Table 1: Chemical Composition of Stainless Steel 316LN

The composition of Stainless Steel 316LN is carefully balanced to achieve its superior strength and corrosion resistance.

Table 2: Typical Mechanical Properties of Stainless Steel 316LN

Stainless Steel 316LN is specifically designed to maintain its strength and shape in high-stress, corrosive environments.

Table 3: Typical Physical Properties of Stainless Steel 316LN

These physical properties highlight the material's ability to perform reliably under a wide range of conditions.

Table4:The Standard of Stainless Steel Seamless Pipe Size Tolerance Size Chart :

TP316LN provides ~40% higher yield strength than TP316L

5. Dimensional Standards & Tolerances

We manufacture TP316LN pipes in strict compliance with international standards:

ASTM / EN / JIS / GB

ASTM A312
EN 10216-5
JIS G3459
GB/T 14976

Typical tolerances:

OD tolerance: ±0.2 mm to ±0.5%
Wall thickness: ±7.5% to ±20%
Length: per standard or customized

Suitable for precision engineering and critical systems

6. Industrial Applications

TP316LN seamless pipes are widely used in high-reliability industries:

Nuclear & Power Generation

Heat exchangers
Reactor systems
Control mechanisms

Chemical & Petrochemical

Urea production
Acetic acid systems
High-pressure reactors

Cryogenic & LNG

LNG pipelines
Liquid oxygen systems
Cryogenic storage tanks

Offshore & Marine

Subsea pipelines
Hydraulic systems
Instrumentation tubing

Pharmaceutical & Food Industry

High-purity process systems
CIP/SIP cleaning environments

7. Quality Assurance & Testing

Every TP316LN pipe is fully inspected and certified:

Certification

EN 10204 3.1 / 3.2 Material Test Certificates (MTC)

Testing & Inspection

100% PMI (Positive Material Identification)
Ultrasonic Testing (UT)
Eddy Current Testing (ET)
Hydrostatic Testing

Advanced Testing

ASTM A262 Intergranular Corrosion (IGC)
Grain size (ASTM E112)
Flattening & flaring tests

Third-Party Inspection

ABS
DNV
BV (Bureau Veritas)
TÜV
SGS

Tensile Strength	Yield Strength	Elongation	Hardness	Brinell Hardness
≥ 515 MPa	≥ 205 MPa	≥ 35%	≤ 192 HBW	≤192 HB

Density	Melting Point	Thermal Expansion	Thermal Conductivity	Modulus of Elasticity	Electrical Resistivity
8.0 g/cm³	1370 - 1400 °C	16.0 µm/m·°C (20-100°C)	16.3 W/m·K (20°C)	193 GPa	0.74 x 10⁻⁶ Ω·m (20°C)

Chemical Composition

Cr	Ni	Mo	N	P	S	Mn	Si	C
16.00 - 18.00	10.00−14.00	2.00−3.00	0.10 - 0.16	≤0.045	≤0.03	≤2.00	≤1.00	≤0.035

Size Tolerance Chart

Standard	OD(D)	Tolerance （MM)		Thickness(S)	Tolerance(MM)	Length	Tolerance
	MM	Common	High	MM			MM
ASTM A312	D ≤48.3	+0.4/-0.8		10.3 ≤73	+20%-12.5%		+6.0/0
	48.3 ≤114.30	±0.8		88.9 ≤457.2,t/D ≤5%	+22.5%/-12.5%
	114.3 ≤219.1	+1.6/-0.8		88.9 ≤457.2,t/D >5%	+15%/-12.5%
	219.1 ≤457.2	+2.4/-0.8		D ≥508, t/D≤5%,SMLS	+22.5%/-12.5%
	457.2 ≤660.4	+3.2/-0.8		D ≥508, t/D>5%,SMLS	+15%/-12.5%
	660.4 ≤863.6	+4.0/-0.8		D ≥508, WELD	+17.5%/-12.5%
	863.6 ≤1219.2	+4.8/-0.8
JIS 3459 Hot-Finished Smls Pipe	D ＜50	±0.51		S ＜4	±0.5
	D ≥50	±1.0%		S ≥4	±12.5%
JIS 3459 Cold-Finished	D ＜30	±0.3		S ＜2	±0.2
	D ≥30	±1.0%		S ≥2	±10.0%
JIS G3463 Hot-Finished Smls Pipe	100	+0.4/-0.8		D ＜100， S	/	D	+7/0
				D ＜100， 2≤S	+40%/0	D	+10/0
				D ＜100， 2.4≤S	+35%/0
				D ＜100， 3.8≤S	+33%/0
				D ＜100， 4.6≤S	+28%/0	D	+13/0
	100 ≤D	+0.4/-1.2		D>100, S ＜2	/
	120 ≤D			D>100 ， 2≤S	/	D	+15/0
	160 ≤D	+0.4/-1.8		D>100 ， 2.4≤S	+35%/0
	200 ≤D	+0.4/-2.4		D>100 ， 3.8≤S	+33%/0	D>50,7	+10/0
				D>100 ， 4.6≤S	+28%/0
JIS G3463 Cold-finished		+0.4/-0.8		D	+0.4/0
	60 ≤D	±0.3		D ≥2.0	+20%/0	D>50,7	+13/0
	80 ≤D	±0.4		D ≥40	+22%/0
	100 ≤D	+0.4/-0.6
	120 ≤D	+0.4/-0.8				D>50,10M	+15/0
	160 ≤D	+0.4/-1.2
	200 ≤D	+0.4/-1.6
GB/T 14975 冷拔(扎)钢管	D	±0.3	±0.1	所有壁厚，普通级PA	+12.5%/-10%
	12.7		±0.15
	38.1	±0.4	±0.3
	88.9	±0.9%	±0.4
	139.7		±0.8	所有壁厚，高级PC	±10%
	203.2		±1.1
	219.1		±1.6
	D ≥323.9		±0.5%
GB/T 14976 冷拔(轧)钢管	6	±0.2	±0.15	S ≤3	±12%(10% /0 高级PC)
	10 ≤D	±0.2	±0.2
	30 ≤D	±0.2	±0.3	S>3	+12.5%/-10%(10%/0 高级PC)
	50 ≤D	0.85%	0.75%
	D>219	0.9%	0.8%	Smin, all	+22%/0(+20%/0 高级PC)

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Send your TP316LN Seamless Pipe enquiry with grade, applicable ASTM/ASME standard and edition, OD × wall thickness, length, quantity, end finish, delivery destination and inspection documents — you will get a written quotation stating the specification and edition, delivery condition, documents included and lead time.

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