The invention provides steel with the tensile strength of 630Mpa for a mobile-type pressure vessel The steel is produced by using one or a mixture of more than two of the following chemical components in percentage by weight: 015-020% of C, 015-040% of Si, 100-170% of Mn, less than or equal to 0015% of P, less than or equal to 0006% of S, 010-030% of Ni, 002-020% of V, 003-03% of Cu, or 001-010% of Cr or 0008-0020% of Ti A production method of the steel comprises the following steps: continuously casting so as to form billet, heating, carrying out hot rolling, and carrying out thermal treatment by adopting a normalizing technology The yield strength of the steel is greater than or equal to 460Mpa, the tensile strength of the steel is 630-730Mpa, the elongation of the steel is greater than or equal to 25%, the yield ratio of the steel is less than or equal to 080, and the steel has good welding properties The hardening capacity of the steel subjected to heat and hot machining is not obvious The steel has low requirements on welding wire energy, welded joints have good mechanical properties, and the steel lays a foundation for the enlargement and weight reduction of the mobile-type pressure vessel and is relatively low in production cost

Steel with tensile strength of 630Mpa for mobile-type pressure vessel and production method thereof

The invention discloses a large-thickness rack steel plate and a production method thereof. The large-thickness rack steel plate comprises, by mass, 0.09%-0.13% of C, 0.20%-0.40% of Si, 1.0%-1.2% of Mn, 0-0.010% of P, 0-0.003% of S, 3.3%-3.6% of Ni, 0.80%-1.0% of Cr, 0.70%-0.80% of Mo, 0.20%-0.30% of Cu, 0.010%-0.030% of Nb, 0.02%-0.05% of V, 0.060%-0.080% of TAl, 0.001%-0.002% of B and the balance Fe and inevitable impurities. According to the large-thickness rack steel plate, the component design is reasonable, and solution strengthening is conducted through the moderate carbon and the manganese; grains are refined by adding a small quantity of the Nb and the V, and carbonitrides of the steel plate play a dispersion strengthening effect; the low-temperature toughness and the certain hardenability of the steel plate are improved by adding the Mo, the Ni and the Cr; when the thickness of the steel plate reaches 210 mm, the half position of the plate thickness still has a good mechanical property of high toughness match.

Large-thickness rack steel plate and production method thereof

A problem to be solved in the invention is providing a production method of a petroleum casing pipe. The production method comprises the following steps: processing a pipe billet to make a steel pipe, and carrying out normalizing and tempering treatment, wherein the chemical components of the pipe billet comprise 0.07-0.15wt% of C, 0.25-0.70wt% of Si, 0.15-0.70wt% of Mn, 0-0.045wt% of P, 0-0.008wt% of S, 6.80-10.4wt% of Cr, 0.64-1.75wt% of Mo, 0.15wt% or less of Cu, 0.03wt% or less of Al, 0.10wt% or less of Ni, and the balance of Fe and inevitable impurities, the normalizing temperature is 950-970DEG C, the normalizing heat insulation time is 50-70min, the tempering temperature is 785-805DEG C, and the tempering heat insulation time is 210-270min; and cooling in a heat treatment furnace to 655-695DEG C at a cooling speed of 40-55DEG C/h after the tempering heat insulation, tapping, and carrying out air cooling. The petroleum casing pipe obtained in the invention has high strength and good impact toughness, and is suitable for underground complex geologic environment.

Production method of petroleum casing pipe

The invention discloses low-cost high-machinability steel for an engineering machine and a manufacturing method of steel. The steel comprises components including, by weight, 0.06% to 0.10% of C, 0.30% to 0.60% of Si, 1.00% to 1.60% of Mn, not larger than 0.015% of P, not larger than 0.0030% of S, 0.20% to 0.60% of Ni, 0.50% to 0.80% of Cr, 0.25% to 0.55% of Mo, 0.025% to 0.065% of V, 0.0008% to 0.0020% of B, 0.008% to 0.018% of Ti, 0.030% to 0.070% of Al, not larger than 0.0050% of N, 0.0010% to 0.0040% of Ca, and the balance Fe and inevitable impurities. Mn/C is larger than 15, {steel plate quenching temperature*[(%Cr)+3.3(%Mo)+1.75(%V)+2.15(%Si)]}/[11.7(%C) +1.23(%Mn)+0.36(%Cu)+(%Ni)] is larger than or equal to 415 and smaller than or equal to 565, Ca/S ranges from 0.80 to 1.50, and (%Ca)*(%S) is larger than or equal to 2.5*10 and smaller than or equal to 2.5*10 . Controlled rolling and two-phase-area quenching and tempering technologies are combined, high strength is obtained, and meanwhile, low-temperature toughness, cold machining moldability, welding performance and fatigue-resisting impact load properties of a steel plate are also excellent.

Low-cost high-machinability steel for engineering machine and manufacturing method of steel

The invention discloses a high-strength quenched and tempered steel plate S500QZ35 with the thickness of 150-200 mm. The high-strength quenched and tempered steel plate S500QZ35 comprises chemical components including, by weight, 0.08-0.13% of C, lower than or equal to 0.20% of Si, 0.85-1.50% of Mn, lower than or equal to 0.013% of P, lower than or equal to 0.005% of S, 0.015-0.050% of Nb, 0.030-0.065% of V, 0.20-0.45% of Mo, 0.40-0.80% of Ni, 0.20-0.45% of Cr, 0.030-0.060% of Als, the balance Fe and the balance residual elements. The sum of the weights of the Cr, the Mo and the V is lower than or equal to 0.85%. Compared with the prior art, the high-strength quenched and tempered steel plate S500QZ35 has the advantages that the uniform and refined internal texture of the high-strength quenched and tempered steel plate S500QZ35 can be effectively guaranteed, the high-strength quenched and tempered steel plate S500QZ35 is stable in performance and high in reproducibility, and special requirements on steel plates for hydroelectric units can be met; the high-strength quenched and tempered steel plate S500QZ35 is excellent in flaw detection quality and can be widely popularized and applied to manufacturing hydroelectric equipment components.

High-strength quenched and tempered steel plate S500QZ35 with thickness of 150-200 mm and method for producing high-strength quenched and tempered steel plate S500QZ35

The invention discloses a 80Kg grade steel plate with ultrahigh toughness and extreme thickness and a manufacturing method of the steel plate. The steel plate comprises the following components in percentage by weight: 0.08-0.13% of C, Si smaller than or equal to 0.10%, 0.80-1.20% of Mn, P smaller than or equal to 0.013%, S smaller than or equal to 0.0030%, 0.20-0.45% of Cu, 1.00-1.60% of Ni, 0.35-0.65% of Cr, 0.30-0.60% of Mo, 0.040-0.070% of Als, 0.010-0.030% of Nb, 0.030-0.060% of V, 0.004-0.010% of Ti, N smaller than or equal to 0.0050%, 0.001-0.004% of Ca, 0.0008-0.0016% of B, and balance of Fe. According to the manufacturing method, a component system of low C-ultralow Si-medium Mn-(Ti+V+Nb+B) microalloyed steel is used as a basis, special rolling control and offline gradient tempering technology (QQ+T) are optimized, so that microstructures of the produced steel plate are small tempered bainite+ tempered martensite, the average crystal colony size is less than 20 microns, excellent obdurability and plasticity match is obtained, and mechanical performance in the direction of the thickness of the steel plate is uniform.

80Kg grade steel plate with ultrahigh toughness and extreme thickness and manufacturing method of the steel plate

High-performance quenched and tempered steel plate with 80 kg carbon equivalent and manufacturing method of high-performance quenched and tempered steel plate

Disclosed are a 60kg-level low-cost and high-toughness steel plate and a production method thereof. The 60kg-level low-cost and high-toughness steel plate comprises, in weight percentage, 0.145%-0.185% of C, not less than 0.30% of Si, 1.35%-1.65% of Mn, not less than 0.013% of P, not less than 0.003% of S, not less than 0.25% of Cu, not less than 0.25% of Ni, 0.005%-0.015% of AlS, 0.150%-0.190% of V, 0.015%-0.020% of N, 0.001%-0.003% of Ca, and the balance of Fe and unavoidable impurities. Based on an alloyed component system of medium C, low Si, high Mn, ultralow AlA and high V with metallurgical technical control, RCR-NT (recrystallization controlled rolling-normalized tempering) processes are optimized, the microstructure of the finished steel plate includes even and small ferrite, pearlite and trace granular bainite, average grain size of the ferrite is smaller than 15 micrometers, even and fine match of high toughness and high plasticity is obtained, and the steel plate has extremely fine low-temperature toughness. The steel plate is especially applicable to large-sized steel structured containers, such as bearing components, petroleum storage tanks, mobile tankers and the like.

Zicheng Liu

Papers

80Kg grade steel plate with ultrahigh toughness and extreme thickness and manufacturing method of the steel plate

High-performance quenched and tempered steel plate with 80 kg carbon equivalent and manufacturing method of high-performance quenched and tempered steel plate

60kg-level low-cost and high-toughness steel plate and production method thereof