不鏽鋼不是不生鏽，是慢生鏽；不鏽鋼也不同級別，燒水壺是低級別的

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Physical Properties of Stainless steels

Designations		Density	Modulus of elasticity	Mean coefficient of thermal expansion [10−6·K−1]		Thermal Conductivity	Specific Heat	Electrical resistivity
EN [N°]	AISI/ASTM	at 20 °C [kg/dm3]	at 20 °C [GPa]	20 °C 200 °C	20 °C 400 °C	at 20 °C [W/(m·K)]	at 20 °C [J/(kg·K)]	at 20 °C [(Ω·mm2)/m]
Austenitic stainless steels
1.4301	304	7,9	200	16,5	17,5	15	500	0,73
1.4401	316	8,0	200	16,5	17,5	15	500	0,75
Duplex stainless steels
1.4462	2205	7,8	200	13,5	14,0 (g)	15	500	0,80
1.4362	2304	7,8	200	13,5	14,0 (n)	15	500	0,80
1.4501		7,8	200	13,5	(n.r.)	15	500	0,80
Ferritic stainless steels
1.4512	409	7,7	220	11,0	12,0	25	460	0,60
1.4016	430	7,7	220	10,0	10,5	25	460	0,60
Martensitic stainless steels
1.4021	420	7,7	215	11,0	12,0	30	460	0,60
1.4418		7,7	200	10,8	11,6	15	430	0,80
Precipitation hardening stainless steels
1.4542	630	7,8	200	10,8	11,6	16	500	0,71