Tool Steel Composition Chart

Chemical composition limits for the principal AISI tool steel types — the M, T, H, A, D, O, S, L, P and W groups. Values are cast or heat analysis ranges in weight percent; a single value is a maximum unless followed by “min”.

wt % all values 13.00-15.00 from–to range 0.30 max maximum limit — not specified (a)–(e) footnote

AISI	UNS	C	Mn	Si	Cr	Ni	Mo	W	V	Co
Molybdenum high-speed steels (M series)
M1	T11301	0.78-0.88	0.15-0.40	0.20-0.50	3.50-4.00	0.30 max	8.20-9.20	1.40-2.10	1.00-1.25	—
M2	T11302	0.78-0.88; 0.95-1.05	0.15-0.40	0.20-0.45	3.75-4.50	0.30 max	4.50-5.50	5.50-6.75	1.75-2.20	—
M3, class 1	T11313	1.00-1.10	0.15-0.40	0.20-0.45	3.75-4.50	0.30 max	4.75-6.50	5.00-6.75	2.25-2.75	—
M3, class 2	T11323	1.15-1.25	0.15-0.40	0.20-0.45	3.75-4.50	0.30 max	4.75-6.50	5.00-6.75	2.75-3.75	—
M4	T11304	1.25-1.40	0.15-0.40	0.20-0.45	3.75-4.75	0.30 max	4.25-5.50	5.25-6.50	3.75-4.50	—
M7	T11307	0.97-1.05	0.15-0.40	0.20-0.55	3.50-4.00	0.30 max	8.20-9.20	1.40-2.10	1.75-2.25	—
M10	T11310	0.84-0.94; 0.95-1.05	0.10-0.40	0.20-0.45	3.75-4.50	0.30 max	7.75-8.50	—	1.80-2.20	—
M30	T11330	0.75-0.85	0.15-0.40	0.20-0.45	3.50-4.25	0.30 max	7.75-9.00	1.30-2.30	1.00-1.40	4.50-5.50
M33	T11333	0.85-0.92	0.15-0.40	0.15-0.50	3.50-4.00	0.30 max	9.00-10.00	1.30-2.10	1.00-1.35	7.75-8.75
M34	T11334	0.85-0.92	0.15-0.40	0.20-0.45	3.50-4.00	0.30 max	7.75-9.20	1.40-2.10	1.90-2.30	7.75-8.75
M35	T11335	0.82-0.88	0.15-0.40	0.20-0.45	3.75-4.50	0.30 max	4.50-5.50	5.50-6.75	1.75-2.20	4.50-5.50
M36	T11336	0.80-0.90	0.15-0.40	0.20-0.45	3.75-4.50	0.30 max	4.50-5.50	5.50-6.50	1.75-2.25	7.75-8.75
M41	T11341	1.05-1.15	0.20-0.60	0.15-0.50	3.75-4.50	0.30 max	3.25-4.25	6.25-7.00	1.75-2.25	4.75-5.75
M42	T11342	1.05-1.15	0.15-0.40	0.15-0.65	3.50-4.25	0.30 max	9.00-10.00	1.15-1.85	0.95-1.35	7.75-8.75
M43	T11343	1.15-1.25	0.20-0.40	0.15-0.65	3.50-4.25	0.30 max	7.50-8.50	2.25-3.00	1.50-1.75	7.75-8.75
M44	T11344	1.10-1.20	0.20-0.40	0.30-0.55	4.00-4.75	0.30 max	6.00-7.00	5.00-5.75	1.85-2.20	11.00-12.25
M46	T11346	1.22-1.30	0.20-0.40	0.40-0.65	3.70-4.20	0.30 max	8.00-8.50	1.90-2.20	3.00-3.30	7.80-8.80
M47	T11347	1.05-1.15	0.15-0.40	0.20-0.45	3.50-4.00	0.30 max	9.25-10.00	1.30-1.80	1.15-1.35	4.75-5.25
M48	T11348	1.42-1.52	0.15-0.40	0.15-0.40	3.50-4.00	0.30 max	4.75-5.50	9.50-10.50	2.75-3.25	8.00-10.00
M62	T11362	1.25-1.35	0.15-0.40	0.15-0.40	3.50-4.00	0.30 max	10.00-11.00	5.75-6.50	1.80-2.10	—
Tungsten high-speed steels (T series)
T1	T12001	0.65-0.80	0.10-0.40	0.20-0.40	3.75-4.50	0.30 max	—	17.25-18.75	0.90-1.30	—
T2	T12002	0.80-0.90	0.20-0.40	0.20-0.40	3.75-4.50	0.30 max	1.00 max	17.50-19.00	1.80-2.40	—
T4	T12004	0.70-0.80	0.10-0.40	0.20-0.40	3.75-4.50	0.30 max	0.40-1.00	17.50-19.00	0.80-1.20	4.25-5.75
T5	T12005	0.75-0.85	0.20-0.40	0.20-0.40	3.75-5.00	0.30 max	0.50-1.25	17.50-19.00	1.80-2.40	7.00-9.50
T6	T12006	0.75-0.85	0.20-0.40	0.20-0.40	4.00-4.75	0.30 max	0.40-1.00	18.50-21.00	1.50-2.10	11.00-13.00
T8	T12008	0.75-0.85	0.20-0.40	0.20-0.40	3.75-4.50	0.30 max	0.40-1.00	13.25-14.75	1.80-2.40	4.25-5.75
T15	T12015	1.50-1.60	0.15-0.40	0.15-0.40	3.75-5.00	0.30 max	1.00 max	11.75-13.00	4.50-5.25	4.75-5.25
Intermediate high-speed steels
M50	T11350	0.78-0.88	0.15-0.45	0.20-0.60	3.75-4.50	0.30 max	3.90-4.75	—	0.80-1.25	—
M52	T11352	0.85-0.95	0.15-0.45	0.20-0.60	3.50-4.30	0.30 max	4.00-4.90	0.75-1.50	1.65-2.25	—
Chromium hot-work steels (H10-H19)
H10	T20810	0.35-0.45	0.25-0.70	0.80-1.20	3.00-3.75	0.30 max	2.00-3.00	—	0.25-0.75	—
H11	T20811	0.33-0.43	0.20-0.50	0.80-1.20	4.75-5.50	0.30 max	1.10-1.60	—	0.30-0.60	—
H12	T20812	0.30-0.40	0.20-0.50	0.80-1.20	4.75-5.50	0.30 max	1.25-1.75	1.00-1.70	0.50 max	—
H13	T20813	0.32-0.45	0.20-0.50	0.80-1.20	4.75-5.50	0.30 max	1.10-1.75	—	0.80-1.20	—
H14	T20814	0.35-0.45	0.20-0.50	0.80-1.20	4.75-5.50	0.30 max	—	4.00-5.25	—	—
H19	T20819	0.32-0.45	0.20-0.50	0.20-0.50	4.00-4.75	0.30 max	0.30-0.55	3.75-4.50	1.75-2.20	4.00-4.50
Tungsten hot-work steels (H21-H26)
H21	T20821	0.26-0.36	0.15-0.40	0.15-0.50	3.00-3.75	0.30 max	—	8.50-10.00	0.30-0.60	—
H22	T20822	0.30-0.40	0.15-0.40	0.15-0.40	1.75-3.75	0.30 max	—	10.00-11.75	0.25-0.50	—
H23	T20823	0.25-0.35	0.15-0.40	0.15-0.60	11.00-12.75	0.30 max	—	11.00-12.75	0.75-1.25	—
H24	T20824	0.42-0.53	0.15-0.40	0.15-0.40	2.50-3.50	0.30 max	—	14.00-16.00	0.40-0.60	—
H25	T20825	0.22-0.32	0.15-0.40	0.15-0.40	3.75-4.50	0.30 max	—	14.00-16.00	0.40-0.60	—
H26	T20826	0.45-0.55 (b)	0.15-0.40	0.15-0.40	3.75-4.50	0.30 max	—	17.25-19.00	0.75-1.25	—
Molybdenum hot-work steels
H42	T20842	0.55-0.70 (b)	0.15-0.40	—	3.75-4.50	0.30 max	4.50-5.50	5.50-6.75	1.75-2.20	—
Air-hardening cold-work steels (A series)
A2	T30102	0.95-1.05	1.00 max	0.50 max	4.75-5.50	0.30 max	0.90-1.40	—	0.15-0.50	—
A3	T30103	1.20-1.30	0.40-0.60	0.50 max	4.75-5.50	0.30 max	0.90-1.40	—	0.80-1.40	—
A4	T30104	0.95-1.05	1.80-2.20	0.50 max	0.90-2.20	0.30 max	0.90-1.40	—	—	—
A6	T30106	0.65-0.75	1.80-2.50	0.50 max	0.90-1.20	0.30 max	0.90-1.40	—	—	—
A7	T30107	2.00-2.85	0.80 max	0.50 max	5.00-5.75	0.30 max	0.90-1.40	0.50-1.50	3.90-5.15	—
A8	T30108	0.50-0.60	0.50 max	0.75-1.10	4.75-5.50	0.30 max	1.15-1.65	1.00-1.50	—	—
A9	T30109	0.45-0.55	0.50 max	0.95-1.15	4.75-5.50	1.25-1.75	1.30-1.80	—	0.80-1.40	—
A10	T30110	1.25-1.50 (c)	1.60-2.10	1.00-1.50	—	1.55-2.05	1.25-1.75	—	—	—
High-carbon, high-chromium cold-work steels (D series)
D2	T30402	1.40-1.60	0.60 max	0.60 max	11.00-13.00	0.30 max	0.70-1.20	—	1.10 max	—
D3	T30403	2.00-2.35	0.60 max	0.60 max	11.00-13.50	0.30 max	—	1.00 max	1.00 max	—
D4	T30404	2.05-2.40	0.60 max	0.60 max	11.00-13.00	0.30 max	0.70-1.20	—	1.00 max	—
D5	T30405	1.40-1.60	0.60 max	0.60 max	11.00-13.00	0.30 max	0.70-1.20	—	1.00 max	2.50-3.50
D7	T30407	2.15-2.50	0.60 max	0.60 max	11.50-13.50	0.30 max	0.70-1.20	—	3.80-4.40	—
Oil-hardening cold-work steels (O series)
O1	T31501	0.85-1.00	1.00-1.40	0.50 max	0.40-0.60	0.30 max	—	0.40-0.60	0.30 max	—
O2	T31502	0.85-0.95	1.40-1.80	0.50 max	0.50 max	0.30 max	0.30 max	—	0.30 max	—
O6	T31506	1.25-1.55 (c)	0.30-1.10	0.55-1.50	0.30 max	0.30 max	0.20-0.30	—	—	—
O7	T31507	1.10-1.30	1.00 max	0.60 max	0.35-0.85	0.30 max	0.30 max	1.00-2.00	0.40 max	—
Shock-resisting steels (S series)
S1	T41901	0.40-0.55	0.10-0.40	0.15-1.20	1.00-1.80	0.30 max	0.50 max	1.50-3.00	0.15-0.30	—
S2	T41902	0.40-0.55	0.30-0.50	0.90-1.20	—	0.30 max	0.30-0.60	—	0.50 max	—
S5	T41905	0.50-0.65	0.60-1.00	1.75-2.25	0.50 max	—	0.20-1.35	—	0.35 max	—
S6	T41906	0.40-0.50	1.20-1.50	2.00-2.50	1.20-1.50	—	0.30-0.50	—	0.20-0.40	—
S7	T41907	0.45-0.55	0.20-0.90	0.20-1.00	3.00-3.50	—	1.30-1.80	—	0.20-0.30 (d)	—
Low-alloy special-purpose steels (L series)
L2	T61202	0.45-1.00 (b)	0.10-0.90	0.50 max	0.70-1.20	—	0.25 max	—	0.10-0.30	—
L6	T61206	0.65-0.75	0.25-0.80	0.50 max	0.60-1.20	1.25-2.00	0.50 max	—	0.20-0.30 (d)	—
Low-carbon mold steels (P series)
P2	T51602	0.10 max	0.10-0.40	0.10-0.40	0.75-1.25	0.10-0.50	0.15-0.40	—	—	—
P3	T51603	0.10 max	0.20-0.60	0.40 max	0.40-0.75	1.00-1.50	—	—	—	—
P4	T51604	0.12 max	0.20-0.60	0.10-0.40	4.00-5.25	—	0.40-1.00	—	—	—
P5	T51605	0.10 max	0.20-0.60	0.40 max	2.00-2.50	0.35 max	—	—	—	—
P6	T51606	0.05-0.15	0.35-0.70	0.10-0.40	1.25-1.75	3.25-3.75	—	—	—	—
P20	T51620	0.28-0.40	0.60-1.00	0.20-0.80	1.40-2.00	—	0.30-0.55	—	—	—
P21	T51621	0.18-0.22	0.20-0.40	0.20-0.40	0.50 max	3.90-4.25	—	—	0.15-0.25	—
Water-hardening tool steels (W series)
W1	T72301	0.70-1.50 (e)	0.10-0.40	0.10-0.40	0.15 max	0.20 max	0.10 max	0.15 max	0.10 max	—
W2	T72302	0.85-1.50 (e)	0.10-0.40	0.10-0.40	0.15 max	0.20 max	0.10 max	0.15 max	0.15-0.35	—
W5	T72305	1.05-1.15	0.10-0.40	0.10-0.40	0.40-0.60	0.20 max	0.10 max	0.15 max	0.10 max	—

^(a) All steels except group W contain 0.25% max Cu, 0.03% max P and 0.03% max S; group W steels contain 0.20% max Cu, 0.025% max P and 0.025% max S. Where specified, sulfur may be increased to 0.06–0.15% to improve machinability of group A, D, H, M and T steels.
^(b) Available in several carbon ranges.
^(c) Contains free graphite in the microstructure.
^(d) Optional.
^(e) Specified carbon ranges are designated by suffix numbers.

Table notes

P21 additionally contains 1.05–1.25% Al (aluminum), specified for resistance to heat checking; Al is not shown as a separate column above.

Two values in the source table were printed with a missing decimal point and are corrected here: M10 chromium reads “3.75-450” in the source and is given as 3.75–4.50; A9 molybdenum reads “1.30-180” and is given as 1.30–1.80.

Composition limits are heat analysis values from the source. Product analysis tolerances may apply — confirm the governing standard (ASTM A681, A600 or A686, or the applicable national standard) with your supplier before ordering.

Grade-level limits for individual steels, such as the H13 chemical composition range, are listed on the grade pages.

Related reference pages

D2 tool steel · H13 tool steel · O1 tool steel · Tool steel equivalent grades · Tool steel properties chart · Tool steel heat treatment guide · Annealing & normalizing temperature chart · Processing & service characteristics · How to select tool steels · Tool steels overview · Stainless steel composition chart

Source: ASM Handbook, Volume 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys, Table 1 “Composition limits of principal types of tool steels” (10th ed.). Reference data for comparison — verify the applicable standard before ordering.