The present invention discloses a high nitrogen steel with high strength, low yield ratio and high corrosion resistance for ocean engineering, comprising the following chemical components by weight percentage: C≤0.01%, Si≤0.1%, Cr 17%-19%, Mn 14%-16%, Mo 1%-1.5%, Ti≤0.05%, N 0.45%-0.6%, P≤0.01%, S≤0.01%, O≤0.02%, and the balance of iron. The present invention also discloses a preparation method as follows: (1) raw material weighing; (2) ingot preparation, remelting and smelting; (3) solution and forging treatments; and (4) hot rolling and post-rolling treatment. A product provided by the present invention has high tensile strength, low yield ratio and high corrosion resistance. At the same time, the present invention does not need pressurized equipment in the preparation process, therefore the preparation method is simple, the cost is low, and the present invention is suitable for industrial popularization in China.

The present invention discloses a high nitrogen steel with high strength, low yield ratio and high corrosion resistance for ocean engineering, comprising the following chemical components by weight percentage: C≤0.01%, Si≤0.1%, Cr 17%-19%, Mn 14%-16%, Mo 1%-1.5%, Ti≤0.05%, N 0.45%-0.6%, P≤0.01%, S≤0.01%, O≤0.02%, and the balance of iron. The present invention also discloses a preparation method as follows: (1) raw material weighing; (2) ingot preparation, remelting and smelting; (3) solution and forging treatments; and (4) hot rolling and post-rolling treatment. A product provided by the present invention has high tensile strength, low yield ratio and high corrosion resistance. At the same time, the present invention does not need pressurized equipment in the preparation process, therefore the preparation method is simple, the cost is low, and the present invention is suitable for industrial popularization in China.

A nitrogen-containing microalloyed spring steel and a preparation method thereof are provided. The chemical components are: 0.45-0.52% of carbon, 0.15-0.35% of silicon, 0.90-1.10% of manganese, 0.90-1.15% of chromium, 0.10-0.25% of molybdenum, 0.10-0.20% of vanadium, 0.025-0.04% of niobium, 0.007-0.012% of nitrogen, less than or equal to 0.03% of lead, tin, zinc, antimony, and bismuth, less than or equal to 25 ppm of oxygen and hydrogen, less than or equal to 0.02% of sulfur and phosphorus, less than or equal to 0.2% of copper, less than or equal to 0.35% nickel, and a balance of iron. The spring steel has significantly improved properties, including high mechanical strength, large elongation, high reduction of area, and good anti-fatigue performance.

A nitrogen-containing microalloyed spring steel and a preparation method thereof are provided. The chemical components are: 0.45-0.52% of carbon, 0.15-0.35% of silicon, 0.90-1.10% of manganese, 0.90-1.15% of chromium, 0.10-0.25% of molybdenum, 0.10-0.20% of vanadium, 0.025-0.04% of niobium, 0.007-0.012% of nitrogen, less than or equal to 0.03% of lead, tin, zinc, antimony, and bismuth, less than or equal to 25 ppm of oxygen and hydrogen, less than or equal to 0.02% of sulfur and phosphorus, less than or equal to 0.2% of copper, less than or equal to 0.35% nickel, and a balance of iron. The spring steel has significantly improved properties, including high mechanical strength, large elongation, high reduction of area, and good anti-fatigue performance.

A nickel-free LPG marine steel plate and a manufacturing method therefor belong to the technical field of high-strength structural steels; the steel plate consists of the following chemical components by mass percentage: 0.18 to 0.24% of C, 0.10 to 0.19% of Si, 16.1 to 18.9% of Mn, less than or equal to 0.012% of P, 0.15 to 0.35% of Mo, 0.10 to 0.25% of RE, and the balance of Fe and inevitable impurities; the steel plate has a yield strength of ≥410 MPa and an impact absorption work of ≥66 J at 150° C., has good low-temperature mechanical properties, can replace 5Ni and 9Ni-based steel, and is used for constructing an LPG storage tank and a relevant structural member at low costs.

A nickel-free LPG marine steel plate and a manufacturing method therefor belong to the technical field of high-strength structural steels; the steel plate consists of the following chemical components by mass percentage: 0.18 to 0.24% of C, 0.10 to 0.19% of Si, 16.1 to 18.9% of Mn, less than or equal to 0.012% of P, 0.15 to 0.35% of Mo, 0.10 to 0.25% of RE, and the balance of Fe and inevitable impurities; the steel plate has a yield strength of ≥410 MPa and an impact absorption work of ≥66 J at 150° C., has good low-temperature mechanical properties, can replace 5Ni and 9Ni-based steel, and is used for constructing an LPG storage tank and a relevant structural member at low costs.

The present invention relates to an iron-based alloy powder wherein the alloy comprises the elements Fe (iron), Cr (chrome) and Mo (molybdenum) and the iron-based alloy powder is produced by an ultra-high liquid atomization process comprising at least two stages as defined below.

A high-performance Nd—Fe—B isotropic magnetic powder and a preparation method thereof are disclosed. The method includes S1, smelting and refining ingredients under vacuum to obtain an alloy ingot, crushing the alloy ingot to obtain an alloy block, wherein the smelting is conducted at a temperature of 1,350-1,450° C., and the refining is conducted at a temperature of 1,335-1,430° C. and a pressure of 900-1,100 Pa in an inert gas atmosphere for 3-7 minutes; S2, melting the alloy block obtained in step S1 to obtain an alloy solution, rapidly quenching the alloy solution to form a Nd—Fe—B rapidly-quenched alloy plate; S3, crushing the Nd—Fe—B rapidly-quenched alloy plate obtained in step S2 to obtain a magnetic powder; S4, subjecting the magnetic powder to a crystallization heat treatment in an inert gas atmosphere, and cooling to obtain the Nd—Fe—B isotropic magnetic powder.

The present invention relates to a manufacturing method of 800 MPa grade steel bar and the 800 MPa grade steel bar produced therefrom. The 800 MPa grade steel bar produced by the manufacturing method comprises, in weight percentages, the following composition: carbon, 0.10%-0.30%; manganese, 7.00%-11.00%; aluminum, 1.00%-3.00%; silicon, 0-1.00%; vanadium, 0.05%-0.30%; niobium; 0-0.10%; and the balance of Fe and inevitable impurities; the manufacturing method comprises the steps of smelting to obtain molten steel containing components of the steel bar; forming the molten steel into a billet by casting; heating the billet to a temperature T1 of 1050° C.≤T1≤1200° C. and thermally insulating for 1.5-2.5 hours; performing hot rolling on the thermally insulated billet, the finishing rolling temperature T2 being 500° C.≤T2≤800° C.; and naturally cooling the hot-rolled billet to ambient temperature. The hot-rolled steel bar of the present invention has a dual-phase microstructure of martensite and austenite. The hot rolled steel bar both has a high yield strength of 800-1000 MPa, an ultra-high tensile strength of 1300 MPa-1900 MPa, an ultra-high tensile to yield ratio of 1.6-2.2, and a high uniform elongation of 8%-20%.

The present invention relates to a manufacturing method of 800 MPa grade steel bar and the 800 MPa grade steel bar produced therefrom. The 800 MPa grade steel bar produced by the manufacturing method comprises, in weight percentages, the following composition: carbon, 0.10%-0.30%; manganese, 7.00%-11.00%; aluminum, 1.00%-3.00%; silicon, 0-1.00%; vanadium, 0.05%-0.30%; niobium; 0-0.10%; and the balance of Fe and inevitable impurities; the manufacturing method comprises the steps of smelting to obtain molten steel containing components of the steel bar; forming the molten steel into a billet by casting; heating the billet to a temperature T1 of 1050° C.≤T1≤1200° C. and thermally insulating for 1.5-2.5 hours; performing hot rolling on the thermally insulated billet, the finishing rolling temperature T2 being 500° C.≤T2≤800° C.; and naturally cooling the hot-rolled billet to ambient temperature. The hot-rolled steel bar of the present invention has a dual-phase microstructure of martensite and austenite. The hot rolled steel bar both has a high yield strength of 800-1000 MPa, an ultra-high tensile strength of 1300 MPa-1900 MPa, an ultra-high tensile to yield ratio of 1.6-2.2, and a high uniform elongation of 8%-20%.