321 / 347 / 316Ti Stainless Steel Pipe | Stabilized Austenitic Stainless Steel | ASTM A312

🟧 Product Overview

Stabilized stainless steel pipes (321 / 347 / 316Ti) are designed to prevent carbide precipitation during welding and long‑term exposure to temperatures between 450–850°C, where standard austenitic stainless steels (304/316) may suffer intergranular corrosion.

321 Stainless Steel Pipe (Ti‑stabilized)

• Titanium added to bind carbon
• Prevents chromium carbide formation
• Ideal for welded structures and thermal cycling environments

347 Stainless Steel Pipe (Nb‑stabilized)

• Niobium (Nb) provides stronger stabilization than Ti
• Better resistance to repeated thermal cycling
• Widely used in high‑temperature pressure vessels

316Ti Stainless Steel Pipe (Mo + Ti stabilized)

• Based on 316 with added titanium
• Combines molybdenum corrosion resistance + stabilization
• Excellent for chemical, marine, and high‑temperature service

Key Advantages:

• Excellent resistance to intergranular corrosion
• Superior weldability for thick‑wall and heavy‑weld applications
• Stable performance in 450–850°C temperature range
• Suitable for high‑temperature and corrosive environments

🟧 Standards

• ASTM A312 / A312M
• ASTM A213
• EN 10216‑5
• JIS G3463
• GB/T 14976

🟧 Grades

• 321 (UNS S32100) — Titanium stabilized
• 347 (UNS S34700) — Niobium stabilized
• 316Ti (UNS S31635) — Titanium stabilized molybdenum alloy

🟧 Product Specifications & Available Sizes

Outer Diameter (OD)

• Seamless: 6–530 mm
• Welded: 12–630 mm

Wall Thickness (WT)

• 0.5–30 mm

Length

• 6 m / 12 m / custom

Type

• Seamless (Cold Drawn / Hot Rolled)
• Welded (ERW / TIG / Laser Welded)

Surface Finish Options

• 2B
• BA
• Polished (180–600 grit)
• Pickled
• Annealed

Dimensions (mm)
Ф21×4	Ф87×17.5	Ф121×19	Ф168×19
Ф21×4.5	Ф89×6-12	Ф124×6.5	Ф168×8
Ф22×6.5	Ф89×15	Ф127×10	Ф170×25
Ф25×8	Ф89×17	Ф127×13	Ф172×18
Ф28×8	Ф91×7.5	Ф127×8	Ф180×10
Ф30×10	Ф92×12	Ф130×12	Ф180×18
Ф30×8	Ф95×10	Ф130×18	Ф180×6
Ф32×8	Ф95×12	Ф133×6-12	Ф180×8
Ф34×6	Ф95×16	Ф133×18	Ф183×18
Ф34×8	Ф95×20	Ф140×8-12	Ф185×18
Ф38×10	Ф95×5.5	Ф140×15	Ф185×20
Ф38×8	Ф95×8	Ф140×20	Ф192×18
Ф40×10	Ф100×8.5	Ф142×18	Ф194×10
Ф40×8	Ф100×13	Ф145×18	Ф194×16
Ф42×5-10	Ф102×6-10	Ф146×10	Ф196×16
Ф45×6-12	Ф102×15	Ф146×12	Ф196×24
Ф48×5-10	Ф104×8.5	Ф152×10	Ф200×20
Ф50×8-12	Ф108×6-10	Ф152×12	Ф219×6-12
Ф51×10	Ф108×13	Ф152×14	Ф219×15
Ф55×10	Ф108×15	Ф152×20	Ф245×10
Ф57×6-10	Ф110×6	Ф152×6	Ф250×25
Ф60×6-12	Ф114×6-10	Ф152×8	Ф273×6-12
Ф65×6-12	Ф114×13	Ф159×6-10	Ф273×34
Ф68×6-12	Ф114×17.5	Ф159×12	Ф325×8-10
Ф70×8	Ф116×12	Ф159×15	Ф355×14
Ф70×10	Ф116×8	Ф159×18	Ф377×10
Ф76×6-12	Ф118×2	Ф159×22	Ф406×14
Ф80×8-12	Ф121×6-11	Ф168×10	Ф457×14
Ф83×8-12	Ф121×16	Ф168×12	Ф508×15

🟧 Chemical Composition

（ASTM A312）

321

Element	Content (%)
C	≤ 0.08
Si	≤ 1.00
Mn	≤ 2.00
P	≤ 0.045
S	≤ 0.030
Cr	17.0–19.0
Ni	9.0–12.0
Ti	≥ 5 × C%

347

Element	Content (%)
C	≤ 0.08
Si	≤ 1.00
Mn	≤ 2.00
P	≤ 0.045
S	≤ 0.030
Cr	17.0–19.0
Ni	9.0–13.0
Nb + Ta	≥ 10 × C%

316Ti

Element	Content (%)
C	≤ 0.08
Si	≤ 1.00
Mn	≤ 2.00
P	≤ 0.045
S	≤ 0.030
Cr	16.5–18.5
Ni	10.5–13.5
Mo	2.0–2.5
Ti	≥ 5 × C%

🟧 Mechanical Properties

（321 / 347 / 316Ti are similar）

Property	Requirement
Tensile Strength	≥ 515 MPa
Yield Strength	≥ 205 MPa
Elongation	≥ 40%
Hardness	≤ 217 HB

🟧 Physical Properties

Property	Value
Density	7.90–7.98 g/cm³
Melting Point	1370–1450°C
Thermal Conductivity	14.0–16.3 W/m·K
Electrical Resistivity	0.72–0.80 μΩ·m

🟧 Manufacturing Processes

• Hot Rolling
• Cold Drawing
• TIG Welding
• Laser Welding
• Stabilizing Annealing
• Pickling
• Polishing
• Eddy Current Testing
• Hydrostatic Testing

🟧 Primary Industry Usage

• Exhaust systems
• Heat exchangers
• Thermal processing equipment
• Chemical and petrochemical piping
• High‑temperature pressure vessels
• Welded structures exposed to 450–850°C
• Marine and offshore equipment（316Ti）

🟧 Why Use Stabilized Stainless Steel Pipe

• Prevents intergranular corrosion after welding
• Ideal for high‑temperature welded structures
• Better long‑term stability than standard 304/316
• 347 offers superior thermal cycling resistance
• 316Ti provides both Mo corrosion resistance + stabilization

🟧 Why Choose WelSteels

• Full range of stabilized stainless steel grades
• Strict quality control with MTC 3.1
• Expertise in high‑temperature and welded‑structure applications
• Seamless & welded options for all stabilized grades
• Global shipping with professional loading supervision
• Competitive pricing for industrial and engineering projects

International Standard of Stainless Steel

NO	China	Japan	America		Korea	Germany	India	Australia
	GB	JIS	ASTM	UNS	KS	DIN	BIS	AS	CNS
Austenitic Stainless Steel
1	12Cr17Mn6Ni5N	SUS201	201	S20100	STS201	1.4372	10Cr17Mn6Ni4N20	201-2	201
2	12Cr18Mn9Ni5N	SUS202	202	S20200	STS202	1.4373	–	–	202
3	12Cr17Ni7	SUS301	301	S20200	STS301	1.4319	10Cr17Ni7	301	301
4	06Cr19Ni10	SUS304	304	S30400	STS304	1.4301	07Cr18Ni9	304	304
5	022Cr19Ni10	SUS304L	304L	S30403	STS304L	1.4306	02Cr18Ni11	304L	304L
6	06Cr19Ni10N	SUS304N1	304N	S30451	STS304N1	1.4315	–	304N1	304N1
7	06Cr19Ni9NbN	SUS304N2	XM21	S30452	STS304N2	–	–	304N2	304N2
8	022Cr19Ni10N	SUS304LN	304LN	S30453	STS304LN	–	–	304LN	304LN
9	10Cr18Ni12	SUS305	305	S30500	STS305	1.4303	–	305	305
10	06Cr23Ni13	SUS309S	309S	S30908	STS309S	1.4833	–	309S	309S
11	06Cr25Ni20	SUS310S	310S	S31008	STS310S	1.4845	–	310S	310S
12	06Cr17Ni12Mo2	SUS316	316	S31600	STS316	1.4401	04Cr17Ni12Mo2	316	316
13	06Cr17Ni12Mo2Ti	SUS316Ti	316Ti	S31635	–	1.4571	04Cr17Ni12MoTi20	316Ti	316Ti
14	022Cr17Ni12Mo2	SUS316L	316L	S31603	STS316L	1.4404	~02Cr17Ni12Mo2	316L	316L
15	06Cr17Ni12Mo2N	SUS316N	316N	S31651	STS316N	–	–	316N	316N
16	022Cr17Ni13Mo2N	SUS316LN	316LN	S31653	STS316LN	1.4429	–	316LN	316LN
17	06Cr18Ni12Mo2Cu2	SUS316J1	–	–	STS316J1	–	–	316J1	316J1
18	022Cr18Ni14Mo2Cu2	SUS316J1L	–	–	STS316J1L	–	–	–	316J1L
19	06Cr19Ni13Mo3	SUS317	317	S31700	STS317	–	–	317	317
20	022Cr19Ni13Mo3	SUS317L	317L	S31703	STS317L	1.4438	–	317L	317L
21	06Cr18Ni11Ti S	SUS321	321	S32100	STS321	1.4541	04Cr18Ni10Ti20	321	321
22	06Cr18Ni11Nb	SUS347	347	S34700	STS347	1.4550	04Cr18Ni10Nb40	347	347
Duplex Stainless Steel
1	–	SUS329J1	329	S32900	STS329J1	1.4477	–	329J1	–
2	022Cr23Ni5Mo3N	–	S32205	F60	–	1.4462	–	2205	2205
3	022Cr25Ni7Mo4N	–	S32750	F53	–	1.4410	–	2507	2507
Ferrite stainless steel
1	06Crl3Al	SUS405	405	S40500	STS405	1.4002	04Cr13	405	405
2	022Cr11Ti	SUH409	409	S40900	STS409	1.4512	–	409L	409L
3	022Cr12	SUS410L	–	–	STS410L	–	–	410L	410L
4	10Cr17	SUS430	430	S43000	STS430	1.4016	05Cr17	430	430
5	10Cr17Mo	SUS434	434	S43400	STS434	1.4113	–	434	434
6	022Cr18NbTi	–	–	S43940	–	1.4509	–	439	439
7	019Cr19Mo2NbTi	SUS444	444	S44400	STS444	1.4521	–	444	444
Martensitic Stainless Steel
1	12Cr12	SUS403	403	S40300	STS403	–	–	403	403
2	12Cr13	SUS410	410	S41000	STS410	1.4006	12Cr13	410	410
3	20Cr13	SUS420J1	410	S42000	STS420J1	1.4021	20Cr13	420	420J1
4	30Cr13	SUS420J2	–	–	STS420J2	1.4028	30 Cr13	420J2	420J2
5	68Cr17	SUS440A	440A	S44002	STS440A	–	–	440A	440A