Tool Steel Thermal Conductivity Chart – W1, H11, H13, H21, T1, T15, M2 | Aobo Steel

Tool Steel Reference Data

Tool Steel Thermal Conductivity Chart

Thermal conductivity versus temperature for seven tool steels — W1, H11, H13, H21, T1, T15 and M2 — in W/m·K and Btu/ft·h·°F, from 95 °C (200 °F) up to 815 °C (1500 °F). Conductivity sets how quickly heat moves through a die or tool: the higher the value, the easier the tool sheds heat to its surroundings.

W/m·K metric conductivity Btu/ft·h·°F imperial conductivity Temp. test temperature

Type	Temp. °C	Temp. °F	W/m·K	Btu/ft·h·°F
W1	95	200	48.3	27.9
	260	500	41.5	24.0
	400	750	38.1	22.0
	540	1000	34.6	20.0
	675	1250	29.4	17.0
	815	1500	24.2	14.0
H11	95	200	42.2	24.4
	260	500	36.3	21.0
	400	750	33.4	19.3
	540	1000	31.5	18.2
	675	1250	30.1	17.4
	815	1500	28.6	16.5
H13	215	420	28.6	16.5
	350	660	28.4	16.4
	475	890	28.4	16.4
	605	1120	28.7	16.6
H21	95	200	27.0	15.6
	260	500	29.8	17.2
	400	750	29.8	17.2
	540	1000	29.4	17.0
	675	1250	29.1	16.8
T1	95	200	19.9	11.5
	260	500	21.6	12.5
	400	750	23.2	13.4
	540	1000	24.7	14.3
T15	95	200	20.9	12.1
	200	500	24.1	13.9
	400	750	25.4	14.7
	540	1000	26.3	15.2
M2	95	200	21.3	12.3
	200	500	23.5	13.6
	400	750	25.6	14.8
	540	1000	27.0	15.6
	675	1250	28.9	16.7

Table notes

Thermal conductivity as a function of temperature, in both metric (W/m·K) and imperial (Btu/ft·h·°F) units. The imperial values equal the metric values × 0.578; the temperature sets differ between grades as printed in the source.

Note: for T15 and M2 the second temperature pair is printed as 200 °C / 500 °F. These are not exact conversions of each other (500 °F = 260 °C); the pairs are reproduced as printed.

H13 sits in a narrow band of about 28.4–28.7 W/m·K from 215 to 605 °C, while the tungsten and molybdenum high-speed steels run roughly 20–29 W/m·K depending on temperature — useful when balancing heat removal in die casting, extrusion and forging tooling. Verify against the applicable heat treatment before design use.

Related reference pages

H13 tool steel · H11 tool steel · H21 tool steel · M2 tool steel · Hot-work tool steels · Hot-work tool steel softening resistance · Tool steel density and thermal expansion · Tool steel hot hardness chart · Tool steel properties chart

Source: ASM Handbook, Volume 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys, Table 12 “Thermal conductivity of selected tool steels” (10th ed., pp. 1817–1819). Reference data for comparison — verify the applicable heat treatment before design use.