X6CrNiTi18-10 (321)

Description

X6CrNiTi18-10 (EN 1.4541 / AISI 321) per EN 10088. Ti addition (5×C min) stabilises carbon as TiC, preventing sensitisation. Can be used in welded condition for continuous service at 400-900 C where 304L would sensitise. Standard for automotive exhaust manifolds, aircraft exhaust ducting and welded chemical equipment in the sensitisation temperature range.

Key Properties — Solution Annealed

Rm (Tensile Strength)

515

MPa

Re / Rp0.2 (Yield)

205

MPa

A₅ (Elongation)

≥ 40.0

Hardness

— – 215

E (Young's Modulus)

193

GPa

Density

7.93

g/cm³

Main Designations (9)

Standard Body	Designation	Country / Region	Note
EN	X6CrNiTi18-10 / 1.4541	EU
AISI/SAE	321	USA
ASTM	A240 / A276 Type 321	USA
UNS	S32100	USA (UNS)
JIS	SUS321	Japan
GOST	08H18N10T (08Kh18N10T)	Russia
BS EN	321S31	UK
AMS	AMS 5510 (sheet/strip)	USA (Aerospace)
JUS	C.4571	Yugoslavia	Ti-stabilised austenitic stainless; JUS C.B2.040

Standards (9)

#	Standard Body	Designation	Country / Region	Note
1	EN	X6CrNiTi18-10 / 1.4541	EU	—
2	AISI/SAE	321	USA	—
3	ASTM	A240 / A276 Type 321	USA	—
4	UNS	S32100	USA (UNS)	—
5	JIS	SUS321	Japan	—
6	GOST	08H18N10T (08Kh18N10T)	Russia	—
7	BS EN	321S31	UK	—
8	AMS	AMS 5510 (sheet/strip)	USA (Aerospace)	—
9	JUS	C.4571	Yugoslavia	Ti-stabilised austenitic stainless; JUS C.B2.040

All values in wt.%

Carbon

≤ 0.0800

Silicon

≤ 1.0000

Manganese

≤ 2.0000

Chromium

17.0000 – 19.0000

Nickel

9.0000 – 12.0000

Titanium

0.4000 – 0.7000

Element	Symbol	Min %	Max %	Typical %
Carbon	C	—	0.0800	0.0400
Silicon	Si	—	1.0000	0.5000
Manganese	Mn	—	2.0000	1.2000
Chromium	Cr	17.0000	19.0000	17.8000
Nickel	Ni	9.0000	12.0000	10.5000
Titanium	Ti	0.4000	0.7000	0.5500

Mechanical Properties

Condition	Code	Rm min MPa	Rm max MPa	Re min MPa	Re max MPa	A₅ min %	Z %	KV J	HB min	HB max	HRC min	HRC max	E GPa
Solution Annealed	+AT	515	—	205	—	40.0	—	—	—	215	—	—	193.0

Physical Properties

Density

7.930

g/cm³

Melting Point

1400–1428

°C

Young's Modulus

193.0

GPa

Poisson's Ratio

0.290

—

Thermal Conductivity

16.1

W/m·K

Thermal Expansion

17.20

×10⁻⁶ /K

Specific Heat

502

J/kg·K

Electrical Resistivity

0.7200

µΩ·m

Magnetic

Heat Treatment

Solution Annealing

Temperature:1020°C – 1120°C

Medium:Water quench

Duration:Sufficient

Cooling:Rapid

Hardness After:<=HB 215

Stabilising anneal at 845-900 C can also be performed to precipitate TiC.

Stabilising Anneal (optional)

Temperature:845°C – 900°C

Medium:Air

Duration:2-4 h

Cooling:Air cool

Hardness After:Unchanged

Maximises sensitisation resistance for very long high-T service.

Machinability

Machinability Rating

relative to AISI B1112 = 100%

42.0%

Difficult

Turning Speed (HSS)

m/min

Turning Speed (Carbide)

m/min

Feed Rate (Turning)

0.110

mm/rev

Drilling Speed (HSS)

m/min

Milling Speed (Carbide)

m/min

Coolant	High-pressure flood coolant
Chip Formation	Long stringy chips; work-hardening
Tool Material	TiAlN carbide; positive rake
Surface Finish	Ra 0.4-1.6 um

TiC particles slightly more abrasive than 304/316 — slightly faster tool wear.

Applications

Automotive

Exhaust manifolds, flexible exhaust couplings and catalytic converter bodies.

Aerospace

Aircraft exhaust ducts, heat shields and firewall panels.

Chemical

Welded chemical equipment for service in the sensitisation temperature range 400-900 C.

Technical Notes

✅

321 vs 316L

316L: best for corrosive aqueous service (welded). 321: best for welded components in HIGH TEMPERATURE service (400-900 C) where sensitisation range is unavoidable. Do not use 321 for aggressive chloride corrosion — use 316L.

💡

Ti Stabilisation

Ti reacts preferentially with C to form TiC (stable to ~900 C), leaving Cr in solid solution. This prevents intergranular corrosion in welds — the key advantage over standard 304.