Chemical composition and tensile yield strength of 15MnNiNbDR cryogenic vessel plate

15MnNiNbDR belongs to the national standard boiler container plate and implements the GB3531 standard. The research and development of 15MnNiNbDR cryogenic vessel plate is a great progress in the raw material of steel plate, which fills the blank of steel between -40 degree and minus 70 degree in the plate for low temperature pressure vessel under -50℃. 15MnNiNbDR steel plate has the characteristics of high toughness and high strength.

Chemical composition of 15MnNiNbDR cryogenic vessel plate:
C: ≤0.18; P: ≤0.020; Si: 0.15-0.50; Ni: 0.30-0.70; Cr: ≤0.45
S: ≤0.010; Mn: 1.20-1.60; Nb: 0.01-0.04; Al: ≤0.015

Tensile yield strength of 15MnNiNbDR cryogenic vessel plate:
Grade: 15MnNiNbDR
Thickness: 6-60
Yield strength (MPa): 370
Tensile strength (MPa): 530-630
Elongation after break A (%): ≥20
180°Cold Bay d=3a
Impact test temperature and impact energy≥60

15MnNiNbDR cryogenic vessel plate surface quality requirements: cracks, bubbles, scars, folds and inclusions
1. The surface of the 15MnNiNbDR steel plate is not allowed to have defects such as cracks, bubbles, scars, folds and inclusions. If there are any of the above surface defects, cleaning is allowed. The cleaning depth is calculated from the actual size of the steel plate and should not exceed half of the thickness tolerance of the steel plate. The minimum thickness of the steel plate should be guaranteed. 15MnNiNbDR steel plate should be smooth, without edges and corners, and should not be delaminated.

2. Other defects are allowed, the depth is calculated from the actual size of the steel plate, and shall not exceed half of the thickness tolerance of the steel plate, and the thickness of the defect shall not be less than the allowable thickness of the steel plate.