Technical Info | Stainless Steel Chemical Composition, Mechanical Properties, Grade Equivalents & Pipe Schedules

Grade Families

Know Your Stainless

Austenitic

300 Series

Non-magnetic, excellent corrosion resistance and formability, weldable, usable from cryogenic to 870 °C. The workhorse of process piping.

304304L316316L316Ti321347310S904L

Duplex

Ferritic-Austenitic

Roughly twice the yield strength of 304/316 with far better chloride stress-corrosion cracking resistance. Ideal for seawater, brine and sour service.

2205 (S32205)2507 (S32750)S327602304

Ferritic

400 Series (Cr)

Magnetic, lower cost, good resistance to stress-corrosion cracking. Used in exhaust, appliances, architectural trim and heat exchanger tubing.

409430439444

Martensitic & PH

Hardenable

Heat-treatable to high hardness and strength. Used for shafts, valve trim, cutlery and pump components where wear resistance matters.

41042043117-4PH

Reference Tables

Data Sheets

Grade	UNS	C max	Mn max	Si max	P max	S max	Cr	Ni	Mo	Others
SS 304	S30400	0.08	2.00	0.75	0.045	0.030	18.0–20.0	8.0–10.5	–	N 0.10 max
SS 304L	S30403	0.030	2.00	0.75	0.045	0.030	18.0–20.0	8.0–12.0	–	N 0.10 max
SS 304H	S30409	0.04–0.10	2.00	0.75	0.045	0.030	18.0–20.0	8.0–10.5	–	–
SS 316	S31600	0.08	2.00	0.75	0.045	0.030	16.0–18.0	10.0–14.0	2.0–3.0	N 0.10 max
SS 316L	S31603	0.030	2.00	0.75	0.045	0.030	16.0–18.0	10.0–14.0	2.0–3.0	N 0.10 max
SS 316Ti	S31635	0.08	2.00	0.75	0.045	0.030	16.0–18.0	10.0–14.0	2.0–3.0	Ti 5×(C+N)–0.70
SS 317L	S31703	0.030	2.00	0.75	0.045	0.030	18.0–20.0	11.0–15.0	3.0–4.0	–
SS 321	S32100	0.08	2.00	0.75	0.045	0.030	17.0–19.0	9.0–12.0	–	Ti 5×(C+N)–0.70
SS 347	S34700	0.08	2.00	0.75	0.045	0.030	17.0–19.0	9.0–13.0	–	Nb 10×C–1.00
SS 310S	S31008	0.08	2.00	1.50	0.045	0.030	24.0–26.0	19.0–22.0	–	–
SS 904L	N08904	0.020	2.00	1.00	0.045	0.035	19.0–23.0	23.0–28.0	4.0–5.0	Cu 1.0–2.0
SS 410	S41000	0.08–0.15	1.00	1.00	0.040	0.030	11.5–13.5	0.75 max	–	–
SS 430	S43000	0.12	1.00	1.00	0.040	0.030	16.0–18.0	0.75 max	–	–
Duplex 2205	S32205	0.030	2.00	1.00	0.030	0.020	22.0–23.0	4.5–6.5	3.0–3.5	N 0.14–0.20
Super Duplex 2507	S32750	0.030	1.20	0.80	0.035	0.020	24.0–26.0	6.0–8.0	3.0–5.0	N 0.24–0.32
Super Duplex	S32760	0.030	1.00	1.00	0.030	0.010	24.0–26.0	6.0–8.0	3.0–4.0	N 0.20–0.30, Cu 0.5–1.0, W 0.5–1.0

Composition in weight %. Single values are maximums unless a range is shown. Values per ASTM A240 / A312 / A182; always refer to the edition specified in your order.

Grade	UNS	Tensile Strength min (MPa)	Yield Strength 0.2% min (MPa)	Elongation min (%)	Hardness max (HB)	Density (g/cm³)
SS 304	S30400	515	205	40	201	7.93
SS 304L	S30403	485	170	40	201	7.93
SS 304H	S30409	515	205	40	201	7.93
SS 316	S31600	515	205	40	217	7.98
SS 316L	S31603	485	170	40	217	7.98
SS 316Ti	S31635	515	205	40	217	7.98
SS 317L	S31703	515	205	40	217	7.98
SS 321	S32100	515	205	40	217	7.92
SS 347	S34700	515	205	40	201	7.96
SS 310S	S31008	515	205	40	217	7.98
SS 904L	N08904	490	220	35	–	8.00
SS 410	S41000	450	205	20	217	7.75
SS 430	S43000	450	205	22	183	7.70
Duplex 2205	S32205	655	450	25	293	7.80
Super Duplex 2507	S32750	800	550	15	310	7.80
Super Duplex	S32760	750	550	25	300	7.80

Typical minimum values in the solution-annealed condition per ASTM A240 (plate). Pipe, fitting and forging specs may differ slightly. Elongation in 50 mm.

Grade	UNS	EN / DIN Number	EN Name	JIS	Pipe (A312)	Fitting (A403)	Forging (A182)	Plate (A240)	Bar (A276)
SS 304	S30400	1.4301	X5CrNi18-10	SUS 304	TP304	WP304	F304	304	304
SS 304L	S30403	1.4307 / 1.4306	X2CrNi18-9	SUS 304L	TP304L	WP304L	F304L	304L	304L
SS 316	S31600	1.4401	X5CrNiMo17-12-2	SUS 316	TP316	WP316	F316	316	316
SS 316L	S31603	1.4404	X2CrNiMo17-12-2	SUS 316L	TP316L	WP316L	F316L	316L	316L
SS 316Ti	S31635	1.4571	X6CrNiMoTi17-12-2	SUS 316Ti	TP316Ti	WP316Ti	F316Ti	316Ti	316Ti
SS 321	S32100	1.4541	X6CrNiTi18-10	SUS 321	TP321	WP321	F321	321	321
SS 347	S34700	1.4550	X6CrNiNb18-10	SUS 347	TP347	WP347	F347	347	347
SS 310S	S31008	1.4845	X8CrNi25-21	SUS 310S	TP310S	WP310S	F310	310S	310S
SS 904L	N08904	1.4539	X1NiCrMoCu25-20-5	–	N08904	WP904L	F904L	904L	904L
Duplex 2205	S32205	1.4462	X2CrNiMoN22-5-3	SUS 329J3L	A790 S32205	A815 S32205	F51 / F60	S32205	S32205
Super Duplex	S32750	1.4410	X2CrNiMoN25-7-4	–	A790 S32750	A815 S32750	F53	S32750	S32750

Nearest equivalents; compositions are not identical across systems. Confirm the governing standard for your project before substituting.

NPS	DN	O.D. inch	O.D. mm	Sch 5S	Sch 10S	Sch 40S / STD	Sch 80S / XS	Sch 160	XXS
1/2	15	0.840	21.3	1.65	2.11	2.77	3.73	4.78	7.47
3/4	20	1.050	26.7	1.65	2.11	2.87	3.91	5.56	7.82
1	25	1.315	33.4	1.65	2.77	3.38	4.55	6.35	9.09
1 1/2	40	1.900	48.3	1.65	2.77	3.68	5.08	7.14	10.15
2	50	2.375	60.3	1.65	2.77	3.91	5.54	8.74	11.07
3	80	3.500	88.9	2.11	3.05	5.49	7.62	11.13	15.24
4	100	4.500	114.3	2.11	3.05	6.02	8.56	13.49	17.12
6	150	6.625	168.3	2.77	3.40	7.11	10.97	18.26	21.95
8	200	8.625	219.1	2.77	3.76	8.18	12.70	23.01	22.23
10	250	10.750	273.0	3.40	4.19	9.27	12.70	28.58	25.40
12	300	12.750	323.8	3.96	4.57	9.53	12.70	33.32	25.40
16	400	16.000	406.4	4.19	4.78	9.53	12.70	40.49	–
24	600	24.000	610.0	5.54	6.35	9.53	12.70	59.54	–

Wall thickness in mm per ASME B36.19M (S schedules) and B36.10M. Full chart on the Pipes page.

Grade	Max Continuous Service (°C)	Intermittent Service (°C)	Scaling Temp in Air (°C)	Min Temp (Cryogenic)
SS 304 / 304L	870	925	870	–196 °C
SS 316 / 316L	870	925	870	–196 °C
SS 321 / 347	870	925	870	–196 °C
SS 310S	1035	1150	1035	–196 °C
SS 904L	400	–	–	–196 °C
Duplex 2205	300	–	–	–50 °C
Super Duplex 2507	300	–	–	–50 °C
SS 410	650	760	705	0 °C

Indicative limits in air. Actual allowable design temperatures depend on the pressure code (ASME B31.3 / Sec VIII) and the service environment.

Quick Reference

Selection Guide

304 or 316?

304 for general water, food, dairy, atmospheric and mild chemical service.
316 / 316L when chlorides, seawater, brine or acids are present — the 2–3% Mo improves pitting resistance.
316L / 304L (low carbon) for welded fabrication to avoid sensitisation.

High Temperature

304H / 316H — higher carbon for creep strength above 540 °C.
321 / 347 — stabilised with Ti / Nb for 425–870 °C service without sensitisation.
310S — up to 1035 °C continuous in furnaces and heat treatment fixtures.

Seawater & Chlorides

Duplex 2205 — PREN ≈ 35, good for brackish and cooling water.
Super Duplex 2507 — PREN ≥ 40, for hot seawater, desalination and offshore.
904L — high Ni / Mo / Cu for sulphuric and phosphoric acid.

PREN Formula

PREN = %Cr + 3.3 × %Mo + 16 × %N
304 ≈ 19 • 316L ≈ 24 • 317L ≈ 30
2205 ≈ 35 • 2507 ≈ 42 • 904L ≈ 34
Higher PREN = better pitting and crevice corrosion resistance.

Weight Formulas

Pipe kg/m = 0.02466 × (OD – WT) × WT
Plate kg/m² = thickness (mm) × 7.93
Round bar kg/m = 0.00623 × D²
Square bar kg/m = 0.00793 × A²

Surface Finishes

No.1 — hot rolled, annealed, pickled (plates)
2B — cold rolled, dull smooth (most sheets)
BA — bright annealed, reflective
No.4 — 150/180 grit brushed satin
No.8 — mirror polished

Technical
Information

Know Your Stainless

300 Series

Ferritic-Austenitic

400 Series (Cr)

Hardenable

Data Sheets

Selection Guide

304 or 316?

High Temperature

Seawater & Chlorides

PREN Formula

Weight Formulas

Surface Finishes

Head Office

Email Us

International Sales

Technical Information

Know Your Stainless

300 Series

Ferritic-Austenitic

400 Series (Cr)

Hardenable

Data Sheets

Selection Guide

304 or 316?

High Temperature

Seawater & Chlorides

PREN Formula

Weight Formulas

Surface Finishes

Head Office

Email Us

International Sales

Technical
Information