According to ASME BPVC Section II, the 9% nickel steel is classified into material group D as a low carbon alloy steel. Its nominal coefficients of thermal conductivity (TC) and thermal diffusivity (TD) at elevated temperatures are listed in below two tables.

Thermal Conductivity (TC) of 9% Nickel Steel At Different Temperatures

*Temp.	70	100	150	200	250	300	350	400	450	500
*T.C	21.0	21.0	21.2	21.3	21.4	21.5	21.5	21.5	21.5	21.4
*Temp.	550	600	650	700	750	800	850	900	950	1000
*T.C	21.3	21.1	20.9	20.7	20.5	20.2	20.0	19.7	19.4	19.1
*Temp.	1050	1100	1150	1200	1250	1300	1350	1400	1450	1500
*T.C	18.8	18.5	18.3	18.0	17.7	17.3	16.3	15.6	15.4	15.3

*Temp.: metal temperature, °F; *T.C: nominal coefficient of thermal conductivity, Btu/hr-ft-°F.

Thermal Diffusivity (TD) of 9% Nickel Steel At Different Temperatures

*Temp.	70	100	150	200	250	300	350	400	450	500
*T.D	0.408	0.401	0.392	0.384	0.377	0.371	0.364	0.357	0.350	0.342
*Temp.	550	600	650	700	750	800	850	900	950	1000
*T.D	0.333	0.324	0.314	0.304	0.294	0.284	0.274	0.263	0.253	0.242
*Temp.	1050	1100	1150	1200	1250	1300	1350	1400	1450	1500
*T.D	0.230	0.218	0.205	0.192	0.177	0.160	0.137	0.073	0.124	0.197

*Temp.: metal temperature, °F; *T.D: nominal coefficient of thermal Diffusivity, ft²/hr.