Patent ID: 8506884

Claim:
A Coriolis hydrogen flow meter for high pressure hydrogen comprising a U shaped sensor tube having inlet side and outlet side tubes, an oscillator for oscillating the sensor tube, a pickup for detecting a displacement of the inlet side and outlet side tubes, and a base to which the inlet side tube and the outlet side tube are fixed, wherein the sensor tube is made of a Fe—Ni base superalloy consisting 1.0 to 3.0 wt % of Nb, 10 to 20 wt % of Cr, 30 to 50 wt % of Fe, 1.0 to 2.0 wt % of Ti, 1.0 to 2.0 wt % of Al, 0.02 wt % or less of C, 0.0011 to 0.039 wt % of N, the balance being Ni and inevitable impurities, wherein an area rate of NbC in a cross sectional structure thereof is 0.4% or less, wherein a ratio of the content of N to that of C is N<2C, and wherein γ′ phase precipitants are formed.