UNS S31700|1.4449|TP317 Seamless Stainless Steel Tube

Seamless Stainless Steel TP317 Tubes (UNS S31700 / W.Nr. 1.4449) are high-alloy austenitic solutions specifically engineered for superior resistance to localized chemical attack and pitting in aggressive environments. As a premier manufacturer based in Wenzhou, China, XinZhe produces high-integrity seamless tubing that strictly complies with ASTM A312, ASTM A213, and ASME SA213 international standards.

Distinguished by its increased Molybdenum (3.0% min) content, our TP317 tubing offers enhanced mechanical properties and superior corrosion resistance compared to standard 316 grades, particularly in acidic chloride environments. These tubes maintain a typical tensile strength of 570 MPa and remain essentially non-magnetic, making them indispensable for mission-critical applications in chemical processing, pulp and paper manufacturing, and aerospace systems. Through advanced cold-drawing and precise solution annealing, XinZhe ensures optimal microstructure and long-term durability for demanding industrial media.

PREN ≈ 28-30 ,higher than TP316L PREN 24-25

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What Is a Seamless Stainless Steel TP317 Tube?

TP317 (UNS S31700) is a high-molybdenum austenitic stainless steel tube containing 3.0–4.0% molybdenum. That molybdenum content is what distinguishes it from TP316: it raises the resistance to pitting, crevice corrosion and chloride attack, and improves performance in sulphur-bearing and acidic process streams, while retaining the good ductility and fabrication behaviour of an austenitic grade.

Seamless Stainless Steel TP317 Tube (UNS S31700 / EN 1.4449) is a high-performance austenitic stainless steel tube with elevated molybdenum content, designed for use in highly corrosive and high-pressure environments.

Manufactured through a seamless process (cold-drawn or hot-finished from a solid billet), TP317 tubes feature:

Compared to welded tubes, TP317 seamless tubes provide greater reliability and safety in critical industrial systems.

Key Features and Technical Advantages

TP317 is an upgraded version of 316/316L, offering:

Maintains strength and oxidation resistance at elevated temperatures.

High Molybdenum Content (3.0% – 4.0%)

Pitting corrosion
Crevice corrosion
Chloride-induced attack

Improved Performance Over 316 Stainless Steel

Better resistance to aggressive chemicals
Longer service life in acidic environments

High Ductility & Fabrication Performance

Easy to bend and form
Ideal for heat exchanger tubing and complex piping systems

1. Superior Corrosion Resistance

Sulfuric acid
Phosphoric acid
Acetic acid
Chloride-rich environments

2. High Pressure & Structural Integrity

Higher pressure tolerance
Reduced failure risk
Longer operational lifespan

Product Specifications and Data

To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Stainless Steel 317.

The composition of Stainless Steel 317 is carefully balanced to achieve its superior corrosion resistance and high strength.

Cr	Ni	P	S	Mo	Mn	Si	C
18.00 - 20.00	11.00 - 15.00	≤ 0.045	≤ 0.030	3.00 - 4.00	≤ 2.00	≤ 1.00	≤ 0.08

Tensile Strength	Yield Strength	Elongation	Hardness
≥ 515 MPa	≥ 205 MPa	≥ 34%	≤ 192 HBW

Density	Melting Point	Thermal Expansion	Thermal Conductivity	Modulus of Elasticity	Electrical Resistivity
8.0 g/cm³	1398 - 1454 °C	16.6 µm/m·°C (20-100°C)	16.3 W/m·K (20°C)	193 GPa	0.74 x 10⁻⁶ Ω·m (20°C)

Standard	OD(D)	Tolerance（MM)		Thickness(S)	Tolerance(MM)	Length	Tolerance
	MM	Common	High	MM			MM
EN 10216-5 HFD	30≤D≤219.1（D2)	±1.0% or ±0.5mm, whicever is the greater(取较大者)		T1, T≤4	±15% or ±0.6mm, whicever is the greater(取较大者)	L≤6M	+5/0
				T2	±12.5% or ±0.4mm, whicever is the greater(取较大者)
	219.1≤D≤610 (D1)	±1.5% or ±0.75mm, whicever is the greater (取较大者)		T≤0.05D	+22.5%/-15%	6≤12	+10/0
				T1, 0.05D≤0.09D	±15% or ±0.6mm, whicever is the greater(取较大者)
				T2, T>0.09D	±12.5% or ±0.4mm, whicever is the greater(取较大者)	L>12	+by agreement/0
EN 10216-5 CFD	D3(D≤219.1)	±0.75% or ±0.3mm, whicever is the greater(取较大者)		T3	±10% or ±0.2mm, whicever is the greater(取较大者)
	D4(D≤219.1)	±0.5% or ±0.mm, whicever is the greater(取较大者)		T4	±7.5% or ±0.15mm, whicever is the greater(取较大者)
ASTM A213 HFD	D≤100	+0.4/-0.8		D<100,S≤2.4	+40%/0	HFD, all size	+5.0/0
		+0.4/-1.2		D<100,2.4≤3.8	+35%/0
		+0.4/-1.6		D<100,3.8≤4.6	+33%/0
				D<100,S>4.6	+28%/0
	100≤200	+0.4/-1.2		D>100, 2.4≤3.8	+35%/0
	200≤225	+0.4/-1.6		D>100,3.8≤4.6	+33%/0
				D>100,S>4.6	+28%/0
ASTM A213 CFD	D<25	±0.10		D≤38.1	+20%/0	CFD, D<50.8	+3.0/0
	25≤D≤40	±0.15
	40	±0.20
	50≤D<65	±0.25
	65≤D<75	±0.30		D>38.1	+22%/0	CFD, D≥50.8	+5.0/0
	75≤D≤100	±0.38
	100≤200	+0.38/-0.64
	200≤225	+0.38/-1.14
ASTM A269	D≤13	±0.13		D≤13	±15%	D<38	+3.2/0
	13	±0.13		13	±10%
	38≤D<89	±0.25				D>38	+4.8/0
	89≤D<140	±0.38
	140≤D<203	±0.76
	203≤D<305	±1.01
	305≤D<356	±1.26
ASTM A270	D<25	±0.13		For weld pipe all size	±12.5%		+3.0/0
	25-50	±0.20
	50-75	±0.25
	75-100	±0.38		For CD SMLS pipe D≤38.1	+20%/0
	100-140	±0.38					+5.0/0
	140-200	±0.75		For CD SMLS pipe D>38.1	+22%/0
	200-300	±1.25

Dimensional Standards and Tolerances

TP317 seamless tubes are supplied to the dimensional tolerances of ASTM A213 / A1016 unless a tighter project specification applies.

Manufactured in compliance with:

ASTM A213 (Boiler & Heat Exchanger Tubes)
ASTM A269 (General Service Tubing)
ASTM A312
EN 10216-5

Common Industrial Applications

Chemical and Petrochemical Industry

Reactors, vessels and heat exchangers
Acid and chloride service piping
Storage and transfer lines

Pulp and Paper Industry

Digester and liquor handling
Bleach plant equipment
Heat exchangers

Marine and Offshore Engineering

Seawater cooling systems
Offshore platform pipework
Desalination piping

Food and Pharmaceutical Processing

Sanitary process lines
Heat exchanger tubing
Corrosive media transfer

Quality Assurance and Manufacturing Process

Certification

All TP317 (UNS S31700) tubes are supplied to ASTM A213 / ASME SA213 and ASTM A312 / ASME SA312 with EN 10204 3.1 mill test certificates. Third-party inspection (SGS, BV, TUV, Lloyd's), PMI reports and full heat-number traceability can be provided on request.

Non-Destructive Testing (NDT)

Hydrostatic or eddy-current testing is performed on 100% of tubes. Ultrasonic testing (UT) and dye-penetrant inspection (PT) are available for critical service, with records retained for each production lot.

Material Verification

Positive Material Identification (PMI) and spectrometric analysis confirm that the chemical composition matches the ordered grade and that the ferrite/austenite balance is within the specified range.

Mechanical Testing

Tensile, yield, elongation and hardness tests are carried out per heat. Impact testing can be supplied at the project design temperature for subsea and low-temperature service.

Dimensional Inspection

Outside diameter, wall thickness, ovality and straightness are measured against ASTM A1016 / A1016M or ASTM A789 tolerances. Length, square-cut ends and end-finish conditions are verified before packing.

TP317 vs TP316 / TP317L – Technical Comparison

TP317 is a high-molybdenum austenitic grade. Comparing it with TP316 and TP317L shows where the extra molybdenum pays off.

Molybdenum Content

TP316: 2–3% Mo, carbon 0.08% maximum
TP317: 3–4% Mo, carbon 0.08% maximum
TP317L: 3–4% Mo, carbon 0.030% maximum

Corrosion Resistance

The step from 2–3% to 3–4% molybdenum measurably raises the PREN, improving resistance to pitting and crevice corrosion in chloride-bearing media and to attack in sulphur-bearing and acidic process streams. That is the reason TP317 is selected over TP316 where chlorides or acids push 316 beyond its limit.

Mechanical and Fabrication Properties

TP317 retains the ductility and fabrication behaviour of an austenitic grade, with good thermal stability and weldability. Its higher carbon than the L grade means welded assemblies should be solution annealed where intergranular corrosion resistance is critical.

Selection Guide

Choose TP317 where higher molybdenum is needed in a non-welded or annealable component
Choose TP317L for welded assemblies in the same service
Choose TP316 where the chloride and acid duty is moderate

Frequently Asked Questions

What is TP317 tube?

TP317 (UNS S31700) is a high-molybdenum austenitic stainless steel tube containing 3.0–4.0% molybdenum. That molybdenum content distinguishes it from TP316 and raises its resistance to pitting, crevice corrosion and chloride attack.

What is the difference between TP317 and TP316?

The molybdenum content: TP317 contains 3–4% against 2–3% in TP316. The extra molybdenum raises the PREN, improving performance in chloride-bearing and acidic process streams and making TP317 the choice where 316 would be marginal.

What is the difference between TP317 and TP317L?

Carbon content. TP317 permits up to 0.08% carbon while TP317L is limited to 0.030%. The low-carbon L grade avoids sensitisation in the heat-affected zone, making it preferable for welded assemblies.

What is TP317 tube used for?

TP317 is used for chemical and petrochemical reactors and heat exchangers, acid and chloride service piping, pulp and paper process equipment and marine and offshore pipework.

Ready to Request a Quotation?

Send your Seamless Stainless Steel TP317 Tube enquiry with grade, application, size (OD and wall thickness or schedule), quantity, length, end finish and inspection requirements. Our technical team will confirm availability, testing scope and lead time.

Request a TP317 Tube Quotation

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