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Low alloy steel plates for pressure vessels operating at subzero temperatures are designated according to their chemical composition and mechanical properties. The grade of such steel plates, published by the Chinese national standards organization, can include Grades H480Y, H340Y, H420Y, H440Y, H460Y, H480YZ and H420YSZ.
H480Y:
This grade is a hot rolled carbon steel plate for pressure vessels. It belongs to the Chinese national standard for hot rolled steel plates for pressure vessels operating at subzero temperature. This grade is made up of 0.20 to 0.50 percent of Carbon and Residual Elements, 0.05 to 0.35 percent of Tungsten, 0.05 to 0.50 percent of Molybdenum, 0.05 to 0.25 percent of Vanadium, 0.015 to 0.030 percent of Boron, 0.0020 percent of Nitrogen and less than 0.03 percent of Cerium in addition to Iron and trace amounts of other elements. The Tensile Strength of this steel grade is minimum 480MPa, and maximum Tensile Strength is 620MPa. The Yield Strength of this steel grade is minimum 375MPa and maximum is 570MPa. The Elongation in 2 inches of this steel grade is 21 percent, and the Brinell Hardness of this steel grade is 150HB or 197HBW.
H340Y:
This grade is also a hot rolled carbon steel plate for pressure vessels, as specified by the Chinese national standards organization. It consists of 0.15 to 0.45 percent of Carbon and Residual Elements, 0.04 to 0.30 percent of Tungsten, 0.03 to 0.30 percent of Molybdenum, 0.04 to 0.15 percent of Vanadium, 0.010 to 0.030 percent of Boron, 0.0020 percent of Nitrogen and less than 0.03 percent of Cerium in addition to Iron and trace amounts of other elements. The Tensile Strength of this grade is minimum 340MPa and maximum strength is 490MPa. The Yield Strength of this steel grade is minimum 275MPa and the maximum Yield Strength is 440MPa. The Elongation in 2 inches of this steel grade is 25 percent, and the Brinell Hardness of this steel grade is 140HB or 187HBW.
H420Y:
This grade is also a hot rolled plain carbon steel plate for pressure vessels, as specified by the Chinese national standards organization. It is a low alloy steel plate composed of 0.17 to 0.25 percent of Carbon and Residual Elements, 0.04 to 0.30 percent of Tungsten, 0.03 to 0.35 percent of Molybdenum, 0.04 to 0.15 percent of Vanadium, 0.010 to 0.030 percent of Boron, 0.0020 percent of Nitrogen and less than 0.03 percent of Cerium in addition to Iron and trace amounts of other elements. The Tensile Strength of this steel grade is minimum 420MPa and maximum strength is 550MPa. The Yield Strength of this steel grade is minimum 315MPa and the maximum Yield Strength is 490MPa. The Elongation in 2 inches of this steel grade is 23 percent, and the Brinell Hardness of this steel grade is 140HB or 187HBW.
H440Y:
This grade is also a hot rolled carbon steel plate for pressure vessels. It is composed of 0.20 to 0.25 percent of Carbon and Residual Elements, 0.05 to 0.30 percent of Tungsten, 0.20 to 0.50 percent of Molybdenum, 0.04 to 0.15 percent of Vanadium, 0.010 to 0.030 percent of Boron, 0.0020 percent of Nitrogen and less than 0.03 percent of Cerium, in addition to Iron and trace amounts of other elements. The Tensile Strength of this steel grade is minimum 440MPa and maximum strength is 580MPa. The Yield Strength of this steel grade is minimum 340MPa and maximum Yield Strength is 530MPa. The Elongation in 2 inches of this steel grade is 22 percent, and the Brinell Hardness of this steel grade is 140HB or 187HBW.
H460Y:
This grade is also a hot rolled carbon steel plate for pressure vessels, as specified by the Chinese national standards organization. It consists of 0.20 to 0.25 percent of Carbon and Residual Elements, 0.05 to 0.30 percent of Tungsten, 0.20 to 0.60 percent of Molybdenum, 0.04 to 0.15 percent of Vanadium, 0.010 to 0.030 percent of Boron, 0.0020 percent of Nitrogen and less than 0.03 percent of Cerium in addition to Iron and trace amounts of other elements. The Tensile Strength of this grade is minimum 460MPa and maximum strength is 600MPa. The Yield Strength of this steel grade is minimum 350MPa and maximum Yield Strength is 550MPa. The Elongation in 2 inches of this steel grade is 21 percent, and the Brinell Hardness of this steel grade is 140HB or 187HBW.
H480YZ:
This grade is similar to the H480Y grade but with the addition of the copper element, up to 0.15 percent, to improve the corrosion-resistant properties of the steel. The chemical composition and mechanical properties of this grade are otherwise similar to the H480Y grade.
H420YSZ:
This grade is also similar to the H420Y grade but with the addition of the copper element, up to 0.15 percent, to improve the corrosion-resistant properties of the steel. The chemical composition and mechanical properties of this grade are otherwise similar to the H420Y grade.
