TP317 Seamless Stainless Steel Tube

UNS S31700 | 1.4449 | ASTM A213

TP317 Seamless Stainless Steel Tube (S31700 / 1.4449) is manufactured to ASTM A213 from stainless steel billet, cold-drawn to the required outside diameter and wall thickness. Supplied from our Wenzhou mill with EN 10204 3.1 mill test certificate, PMI and dimensional inspection on request.

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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.

Produced 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.

TP317 Key Features and Technical Advantages

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

Maintains strength and oxidation resistance at elevated temperatures.

Feature	Description
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

TP317 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
Standard	MM	Common	High	MM	Tolerance(MM)	Length	MM
EN 10216-5 HFD	30≤D≤219.1（D2)	±1.0% or ±0.5mm, whicever is the greater		T1, T≤4	±15% or ±0.6mm, whicever is the greater	L≤6M	+5/0
	30≤D≤219.1（D2)	±1.0% or ±0.5mm, whicever is the greater		T2	±12.5% or ±0.4mm, whicever is the greater	L≤6M	+5/0
	219.1≤D≤610 (D1)	±1.5% or ±0.75mm, whicever is the greater		T≤0.05D	+22.5%/-15%	6≤12	+10/0
				T1, 0.05D≤0.09D	±15% or ±0.6mm, whicever is the greater	6≤12	+10/0
				T2, T>0.09D	±12.5% or ±0.4mm, whicever is the greater	L>12	+by agreement/0
EN 10216-5 CFD	D3(D≤219.1)	±0.75% or ±0.3mm, whicever is the greater		T3	±10% or ±0.2mm, whicever is the greater
EN 10216-5 CFD	D4(D≤219.1)	±0.5% or ±0.mm, whicever is the greater		T4	±7.5% or ±0.15mm, whicever is the greater
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
		+0.4/-1.6		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
	200≤225	+0.4/-1.6		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%	D＜38	+3.2/0
	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		For CD SMLS pipe D≤38.1	+20%/0		+5.0/0
	140-200	±0.75		For CD SMLS pipe D>38.1	+22%/0
	200-300	±1.25		For CD SMLS pipe D>38.1	+22%/0

TP317 Dimensional Standards and Tolerances

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

Produced in compliance with:

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

TP317 Common Industrial Applications

Industry	Typical 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

TP317 Quality Assurance and Production Process

Process Step	Description
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 About TP317 Seamless Stainless Steel Tubes

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.

Request a TP317 Tube 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