78results about How to "Improve hardenability" patented technology

The invention discloses high-toughness cold-rolled dual-phase steel, a preparation method thereof and an automobile part, and belongs to the technical field of alloy production. The high-toughness cold-rolled dual-phase steel comprises the following chemical components in percentage by weight: 0.15%-0.35% of C, 0.10%-0.50% of Si, 0.50%-4.00% of Mn, less than or equal to 0.5% of Mo, Nb, Ti and V, and the balance of Fe and impurity elements, the matrix structure of the dual-phase steel is long lath ferrite and martensite. The high-toughness cold-rolled dual-phase steel with the chemical components and the matrix structure has excellent toughness while having ultrahigh strength, the reaming and cold bending properties of the dual-phase steel are effectively improved, and the high-toughness cold-rolled dual-phase steel can be applied as an excellent automobile part. The preparation method of the high-strength and high-toughness cold-rolled dual-phase steel comprises the following step of preparing raw materials according to preset chemical components of the high-strength and high-toughness cold-rolled dual-phase steel. The method is simple, easy to operate and suitable for industrial production.

The invention discloses hot rolled steel for a 500MPa-grade high-ductility hollow anchor rod welded pipe as well as a preparation method and application of the hot rolled steel, and belongs to the technical field of hot continuous rolling plate strip production. The hot rolled steel for the 500MPa-grade high-ductility hollow anchor rod welded pipe is prepared through smelting, casting blank heating, rough rolling, coiling of a hot coiling box, finish rolling, laminar cooling and coiling. The yield strength is larger than or equal to 500 MPa, the tensile strength is larger than or equal to 600 MPa, the percentage elongation after fracture is larger than or equal to 26%, and the maximum force percentage elongation is larger than or equal to 14%. The hot rolled steel is subjected to the machining procedures of heating of a high-frequency electric heating device, three-roller spinning equal-diameter rolling, online heat treatment, saw cutting and slow cooling of a cooling bed, and a hollow anchor rod body is obtained; the yield force is larger than or equal to 150 kN, the tensile resistance is larger than or equal to 200 kN, and the maximum force elongation is larger than or equal to 6%. The method can effectively solve the problem that the ductility of the hollow anchor rod body prepared after heat treatment is poor due to the fact that existing anchor rod steel cannot have strength and ductility at the same time.

The invention discloses a method for improving the interlayer performance uniformity of a large-size high-toughness 7xxx aluminum alloy pre-stretched super-thick plate, and relates to the field of improvement of interlayer performance differences of high-strength aluminum alloy pre-stretched super-thick plates. The method aims at solving the problems that in the subsequent part machining and application process of the 7xxx alloy super-thick pre-stretched thick plate, the performance difference of a plate thickness layer is large, the damage resistance of the position where the performance of the plate is weak is reduced, the part loses efficacy, and the model safety is reduced. The method comprises the steps of controlling the uniformity of cross-section structure components of a large-size cast ingot, performing strong rolling deformation of plate interlayer performance uniformity, and performing strong quenching for improving the hardenability of the plate. According to the plate prepared through the method, the bottleneck that the comprehensive performance of the plate is synergistically improved is broken through, the overall performance of the thick plate is improved, the service life of parts is prolonged, the structural safety is enhanced, and the market competitiveness of products is improved. The method disclosed by the invention is used for controlling the interlayer performance uniformity of the 7xxx large-specification, super-thick and ultrahigh-strength aluminum alloy pre-stretched thick plate.

The invention discloses a Ti-V-Zr-Cr-Al series ultrahigh-strength near-beta titanium alloy and a preparation method, and belongs to the technical field of titanium alloy materials, the ultrahigh-strength near-beta titanium alloy comprises, by mass, 5.0%-5.5% of Al, 11.0%-11.5% of V, 2.5%-3.0% of Cr, 4.5%-5.0% of Zr and the balance Ti and inevitable impurity elements; in the preparation process, firstly, an alloy ingot is subjected to blooming forging and cooled to a phase transformation point for upsetting forging, a certain amount of primary alpha phases are formed in the alloy and evenly distributed in beta crystal grains, and a titanium alloy forging stock is obtained; and then the titanium alloy forging stock is sequentially subjected to solution treatment and aging treatment, and the near-beta ultra-high-strength titanium alloy of the double-state structure is obtained. The tensile strength exceeds 1800 MPa, the yield strength reaches 1780 MPa, the elongation at break is larger than 3.2%, and the uniform elongation is larger than 2.8%. Particularly, the tensile strength reaches 1800 MPa, the requirements of the fields of aerospace, the energy industry and the like can be met, and high use value and popularization value are achieved.

The invention relates to the field of metal materials and petroleum machinery, in particular to VBRE low-carbon low-alloy steel for a pressure-bearing part of an ultra-deep well blowout preventer group and a preparation method of the VBRE low-carbon low-alloy steel. The steel comprises the following chemical components in percentage by weight: 0.05 to 0.15 percent of C, 0.05 to 0.35 percent of Si, 0.40 to 0.80 percent of Mn, 2.0 to 3.0 percent of Cr, 0.80 to 1.20 percent of Mo, 0.05 to 0.25 percent of V, 0.0005 to 0.0030 percent of B, 0.0020 to 0.030 percent of RE and the balance of Fe. A series of key technologies such as purification smelting, high-purity rare earth treatment, argon protection pouring, cast ingot high-temperature demolding, high-temperature diffusion annealing, homogeneous forging forming and thermal refining are adopted, and the defects of internal component segregation, shrinkage cavity and porosity, non-metallic inclusion, uneven tissue, unstable performance and the like of the ultra-deep well blowout preventer set pressure-bearing part are greatly reduced; the VBRE low-carbon low-alloy steel for the pressure-bearing part of the blowout preventer group of the ultra-deep well, which has the characteristics of purity, homogeneity, compactness, refinement and the like and excellent obdurability matching, is obtained, and the service performance requirements of high strength, high toughness, heat resistance, corrosion resistance, fatigue resistance and the like are met.

This invention discloses a 440MPa grade steel plate with ultra-low temperature toughness and its preparation method, belonging to the field of steel materials technology. It solves the contradiction between insufficient strength and toughness grades and excessive nickel content in existing low-temperature steels. The composition of the 440MPa grade steel plate with ultra-low temperature toughness, by mass percentage, includes: C: 0.030%–0.085%, Si: 0.18%–0.38%, Mn: 0.95%–1.35%, P: ≤0.010%, S: ≤0.003%, Cr: 0.01%–0.25%, Mo: 0.01%–0.15%, Ni: 3.20%–4.25%, Cu: 0.12%–0.85%, Nb: 0.008%–0.035%, Al: 0.02%–0.036%, Ti: 0.008%–0.022%, with the balance being Fe and other unavoidable impurities. The steel plate of this invention exhibits excellent strength and low-temperature toughness.

The invention discloses 1000MPa-grade hydroelectric steel with optimized low-temperature toughness and a preparation method of the 1000MPa-grade hydroelectric steel, and belongs to the technical field of steel production. The 1000MPa-grade hydroelectric steel with the optimized low-temperature toughness is prepared from the following chemical components in percentage by weight: 0.03 to 0.09 percent of C, 0.80 to 1.40 percent of Mn, 0.10 to 0.15 percent of Si, 0.05 to 0.14 percent of Cu, less than or equal to 0.003 percent of S, less than or equal to 0.01 percent of P, 0.01 to 0.04 percent of Al, 0.03 to 0.10 percent of V, 0.03 to 0.06 percent of Cr, 0.3 to 0.65 percent of Mo, 0.001 to 0.002 percent of B, 0.01 to 0.018 percent of Ti, 0.015 to 0.025 percent of Nb, 0.18 to 0.60 percent of Ni and the balance of Fe and other inevitable impurities. The preparation method comprises a steel-making process, a heating process, a rough phosphorus removal process, a rolling process and a heat treatment process. By optimizing the chemical components and the preparation process of the 1000MPa-grade hydroelectric steel, the low-temperature toughness of the 1000MPa-grade hydroelectric steel is remarkably improved on the basis that the 1000MPa-grade hydroelectric steel with high strength is obtained, and the 1000MPa-grade hydroelectric steel is suitable for industrial application.

The present application relates to a HRB500E earthquake-resistant steel bar and a preparation method thereof, belonging to the technical field of earthquake-resistant steel bar production. The chemical composition of the steel bar comprises: C: 0.20 wt%-0.25 wt%, Si: 0.50 wt%-0.75 wt%, Mn: 1.20 wt%-1.40 wt%, P: ≤0.030 wt%, S: ≤0.030 wt%, V: 0.05 wt%-0.08 wt%, Fe; the metallographic structure of the steel bar is: ferrite and pearlite. The preparation method of HRB500E earthquake-resistant steel bars provided in the present application eliminates the heating step of the heating furnace, and is optimized from the aspects of composition control, continuous casting billet drawing speed control, direct rolling insulation roller conveying control, start rolling temperature, finishing rolling entrance temperature, wire drawing temperature, air cooling process, roller speed, etc. The produced HRB500E earthquake-resistant steel bars have excellent organizational properties, mechanical properties, and earthquake-resistant properties, with performance parameters Rp0.2≥520Mpa, tensile strength Rm≥700Mpa, elongation≥18%, Agt≥9%, strength-to-yield ratio≥1.25, and yield-to-yield ratio≤1.2.

A pre-hardened steel plate for a mirror-surface mold, comprising elements as follows: C: 0.28 to 0.36%, Si: 0.50 to 0.80%, Mn: 1.20 to 1.50%, P ≤ 0.020%, S ≤ 0.010%, Cr: 1.30 to 1.80%, Mo: 0.30 to 0.50%, Ni: 0.65 to 0.90%, V: 0.15 to 0.30%, H ≤ 1.5 ppm, and the balance is Fe and inevitable impurities. A pre-hardened steel plate with high hardenability for a mirror-surface mold having is obtained by using a manufacturing method comprising subjecting continuous casting billets to processes such as rolling, offline slow cooling, normalizing and tempering heat treatments. The advantages of the manufacturing method lie in that the production efficiency of continuous casting is high, the manufacturing costs are low. When not quenched-and-tempered, the hardness of the steel plate having a thickness of 20-180 mm reaches 38-42 HRC, the hardness fluctuation of the entire thickness ≤ 2 HRC, and the level of flaw detection satisfies the requirement of of level I in GB / T2970.

The utility model discloses an oil quenching device for steel ball processing, which relates to the technical field of steel ball processing and comprises a quenching pool, a cooling pool is arranged on one side of the quenching pool, quenching oil is arranged in the quenching pool and the cooling pool and circulates circularly, and a feeding mechanism is soaked in the quenching pool. According to the oil quenching device for steel ball machining, the cooling pool is arranged, quenching oil in the quenching pool is cooled, the quenching effect of steel balls is better, on the other hand, automatic quenching, automatic feeding and automatic discharging of the steel balls are achieved through the feeding mechanism, and the production efficiency is improved.

The invention relates to the technical field of bolt production, and particularly discloses a high-strength bolt machining process and device. Comprising the following steps: S1, material selection: selecting an alloy steel blank containing C, Si, Mn, Cr, Mo, V and the balance of Fe; s2, cold heading forming is conducted, specifically, the alloy steel blank is placed in a multi-station cold heading machine, and a bolt blank is formed through continuous cold heading and forging; s3, heat treatment is conducted, specifically, the bolt blank is subjected to quenching treatment and then subjected to tempering treatment, and a bolt base body is obtained; and S4, surface treatment is conducted, specifically, phosphating treatment is conducted on the surface of the bolt base body in sequence to form a phosphating layer, the composite coating is coated, and the high-strength bolt is obtained. The high-strength bolt machining process can be used for manufacturing connecting components requiring high reliability under complex working conditions such as heavy load, vibration and impact, and the high-strength bolt machining process has the advantages that the toughness, fatigue resistance and delayed fracture resistance are improved while high strength is kept.

The invention discloses a chromium and vanadium microalloying outlet R350HT heat treatment steel rail and a production method thereof. The R350HT heat-treated steel rail at the chromium and vanadium microalloying outlet, provided by the invention, comprises the following chemical components in percentage by mass: 0.76-0.80% of C; 0.50 to 0.58% of Si; 1.0 to 1.20 parts of Mn; p < = 0.020; s is less than or equal to 0.025; 0.10 to 0.15 percent of Cr, 0.01 to 0.03 percent of V and the balance of Fe and impurities. By optimizing the component design and the production process, the R350HT heat treatment steel rail provided by the invention has excellent wear resistance and very high strength and hardness.

This application provides a quenched and tempered steel plate and its production method. The quenched and tempered steel plate comprises the following components by mass percentage: C: 0.15–0.20%; Si: 0.20–0.40%; Mn: 1.20–1.50%; Cr: 0.20–0.50%; Ni: 0.10–0.20%; Nb: 0.020–0.040%; Ti: 0.010–0.040%; Mo: 0.30–0.50%; B: 0.0010–0.0025%; P≤0.015%, S≤0.004%; N≤0.004%, Als: 0.010–0.060%, with the remainder being Fe and unavoidable impurities. This application manufactures a thick, high-strength quenched and tempered steel plate with high surface quality by adjusting the elemental composition and content of the quenched and tempered steel plate, specifically by adding certain amounts of Ni, Cr, and B.

The invention belongs to the technical field of fastening connection, and particularly relates to corrosion-resistant steel with the grade being 8.8 or above, a duct piece bolt and a preparation method of the duct piece bolt. By compounding Cu and Ni, a compact and stable rust layer is promoted to be formed on the surface of the material, further corrosion is prevented, and the corrosion resistance of the material is improved; through trace Sn, a compound of SnO2 and graphite can be formed on the surface of the material to serve as an anti-corrosion layer, and the corrosion resistance of the material is greatly enhanced; by optimizing the content of C and adding a trace amount of B, the hardenability of the steel is improved so as to meet the performance requirements of the large-specification duct piece bolt of the tunnel. According to the corrosion-resistant steel with the grade of 8.8 or above, specific elements with specific contents are adopted, the excellent corrosion resistance is achieved, the mechanical performance is good, and the comprehensive performance is excellent.

The invention discloses a mining bimetallic chain wheel and a manufacturing method thereof, and the manufacturing method comprises the following steps: carrying out forging treatment on a bimetallic profile blank by adopting a three-fire forging forming mode; normalizing the chain wheel formed by forging; carrying out rough machining on a tooth groove, an inner hole, an outer circle and an end face on the normalized chain wheel blank; quenching and tempering heat treatment is conducted on the chain wheel base body; semi-finish machining is conducted on the outer circle and the tooth form of the chain wheel base body; and finish machining of the teeth. The chain wheel sheet material can meet the requirements that a chain wheel is low in appearance hardness, high in abrasion resistance and not prone to abrasion in the using process. The material of the connecting sleeve can meet the requirements of low appearance hardness and soft inner hole hardness of the chain wheel, and teeth are easy to manufacture. And the blank three-fire forging process is adopted, so that grains in the blank can be refined.

The invention relates to quenched and tempered steel for a large-specification wind power fastener. The fastener steel comprises the following chemical components in percentage by mass: 0.38 to 0.45 percent of C, 0.22 to 0.30 percent of Si, 1.52 to 1.60 percent of Mn, less than or equal to 0.011 percent of P, 0.008 to 0.025 percent of S, 0.55 to 0.65 percent of Ni, 1.21 to 1.31 percent of Cr, 0.50 to 0.58 percent of Mo and the balance of Fe and inevitable impurity elements. The whole technological process comprises the steps of burdening, KR molten iron pretreatment, converter or electric furnace smelting, LF refining (sulfide denaturation treatment), degassing, continuous casting, warm conveying to a heating furnace, heating, high-pressure water descaling, rolling, waste heat quenching treatment, tempering, turning, packaging and warehousing. The diameter of the fastener steel ranges from 80 mm to 130 mm, the martensite content of the core area after overall quenching reaches 90% or above, the core-surface hardness difference after quenching is controlled within 3 HRC, and the fastener steel achieves large specification, high dimensional precision and excellent comprehensive mechanical performance at the same time.

This invention discloses a type of steel for hydropower engineering and its preparation method. The steel comprises the following chemical components: C, Mn, Si, Alt, Nb, V, Ti, Cr, Ni, Mo, Cu, and B. Its yield strength is ≥950 MPa, tensile strength is ≥1000 MPa, and it exhibits excellent load-bearing capacity, meeting the structural material requirements for high-stress conditions in large-scale hydropower projects. Its impact value at -40℃ is ≥200 J, and its aging impact value at -40℃ is ≥200 J, demonstrating excellent low-temperature toughness and aging stability. It exhibits outstanding resistance to low-temperature brittle fracture and long-term service embrittlement, providing strong service safety and durability. It is suitable for critical load-bearing structures in hydropower projects operating in cold, high-stress, and long-term service conditions.

The invention belongs to the technical field of fastening connection, and particularly relates to corrosion-resistant steel with the grade of 6.8 or above, a duct piece bolt and a preparation method of the duct piece bolt. By compounding Cu and Ni, a compact and stable rust layer is promoted to be formed on the surface of the material, further corrosion is prevented, and the corrosion resistance of the material is improved; through trace Sn, a compound of SnO2 and graphite can be formed on the surface of the material to serve as an anti-corrosion layer, and the corrosion resistance of the material is greatly enhanced; by optimizing the content of C and adding a trace amount of B, the hardenability of the steel is improved so as to meet the performance requirements of the large-specification duct piece bolt of the tunnel. According to the corrosion-resistant steel with the grade of 6.8 or above, specific elements with the specific content are adopted, the steel does not depend on a coating, the excellent corrosion resistance is achieved, the mechanical performance is good, and the comprehensive performance is excellent.

The present invention relates to the field of material science and metal processing technology, and discloses a high-strength and toughening heat treatment process for thick-walled forgings for pressure vessels, comprising the following steps: S1, selecting a low-alloy steel material containing a specific proportion of vanadium, molybdenum, manganese, silicon and nickel; S2, gradually preheating the forging in a furnace to 450°C to 500°C, and continuously heating for 2 hours; S3, heating the forging to 870°C to 920°C, and adjusting the holding time according to the thickness of the forging to ensure that the heat is fully penetrated; S4, carburizing treatment is performed at 680°C to 720°C for 8 to 12 hours; S5, using oil for rapid cooling, and then air cooling to room temperature. The present invention significantly improves the hardness and toughness of the forging, while enhancing its corrosion resistance and fatigue life, and optimizing the microstructure of the material, so that the forging is suitable for the field of pressure vessel manufacturing with high requirements.

The application discloses a 27MnTiB high-strength wear-resistant steel plate and a production method thereof. By adopting a reasonable controlled rolling and controlled cooling process, cooperating with on-line quenching, stacking slow cooling and rapid low-temperature tempering, the 27MnTiB steel plate can not only obtain relatively high hardness and strength, but also obtain relatively high impact toughness, directly meeting the requirements of high-strength wear-resistant steel, with the yield strength being greater than or equal to 1500MPa, the tensile strength being greater than or equal to 1650MPa, the elongation being greater than or equal to 9%, the impact energy being greater than or equal to 60J, and the hardness being greater than or equal to 450HB. Meanwhile, the processing and manufacturing process is simplified, and the processing cost is reduced.

The invention belongs to the technical field of rolling, and relates to a rolling process for preparing ER50-6E welding wire steel with the tensile strength not larger than 1360 MPa and application of the ER50-6E welding wire steel. Billet steel is continuously fed, the in-furnace time is controlled to be not shorter than 110 minutes, the heating temperature is 1100-1150 DEG C, and the soaking temperature is 1170-1220 DEG C; the initial rolling temperature is 1070 DEG C to 1120 DEG C; the finish rolling temperature is not lower than 960 DEG C; and the water amount of finish rolling cooling water is reduced so that the finish rolling outlet temperature can be increased to be not lower than 1050 DEG C, the spinning temperature can be 920-950 DEG C, a heat preservation cover is completely closed, the roller way speed is low, and the cover outlet temperature is controlled to be 650 DEG C or below. The tensile strength of a hot-rolled wire rod does not exceed 500 MPa, the yield strength does not exceed 310 MPa, the yield ratio does not exceed 0.63, the hot-rolled wire rod is suitable for drawing a 0.8 mm welding wire from a phi 6.5 mm wire rod, the tensile strength of the welding wire is not larger than 1360 MPa, and the hot-rolled wire rod has good wire feeding performance.

The application discloses a Ti-V-Zr-Cr-Al system ultrahigh-strength near-beta titanium alloy and a preparation method thereof, and belongs to the technical field of titanium alloy materials. The ultrahigh-strength near-beta titanium alloy contains 5.0-5.5% of Al, 11.0-11.5% of V, 2.5-3.0% of Cr, 4.5-5.0% of Zr, and the balance of Ti and inevitable impurity elements according to mass percentage. In the preparation process, firstly, the alloy ingot is subjected to open forging, and then is subjected to upsetting and drawing forging after being cooled to a phase transition point, so that a certain amount of primary alpha phase is formed in the alloy and is uniformly distributed in beta grains, thereby obtaining a titanium alloy forging blank; and then, the titanium alloy forging blank is sequentially subjected to solid solution treatment and aging treatment, thereby obtaining a near-beta ultrahigh-strength titanium alloy with a duplex structure. The titanium alloy has a tensile strength of more than 1800 MPa, a yield strength of 1780 MPa, a fracture elongation of more than 3.2%, and a uniform elongation of more than 2.8%. In particular, the tensile strength reaches 1800 MPa, and the titanium alloy can meet the requirements of the fields of aerospace, energy industry and the like, and has high use value and popularization value.

The invention discloses a production method for improving the impact toughness stability of thick-specification high-strength steel Q690D. The thick-specification high-strength steel Q690D comprises the following chemical components in percentage by weight: 0.13-0.15% of C; 0.25 to 0.35 percent of Si; mn: 1.40% to 1.50%; 0.080% to 0.110% of Nb, V and Ti; 0.85 to 1.05 percent of Cr, Mo and Ni; less than or equal to 0.015% of P; s < = 0.005%; b: 0.0008% to 0.0015% of the total weight of the The content of Als is 0.015 to 0.030 percent; o: < = 0.0035%; n: less than or equal to 0.0050%; the production method comprises the steps of KR desulfurization, converter smelting, LF refining, RH refining, continuous casting, heating, rolling and heat treatment. The invention aims to meet the depth requirement of the through quenching layer of the thick steel plate, ensure the strength performance of the high-strength steel Q690D and avoid great fluctuation of low-temperature toughness caused by the boron element.

This application relates to a hot-rolled pickled duplex steel and its preparation method, belonging to the field of strip steel production technology. The chemical composition of the duplex steel, by mass fraction, is: C: 0.05%~0.15%, Si: 0.15%~1.50%, Mn: 1.0%~2.0%, Al: 0.02%~0.10%, P≤0.015%, S≤0.006%, Cr: 0.1%~0.5%, Nb: 0.01%~0.05%, Ti: 0.01%~0.03%, Ni: 0.01%~0.40%, V: 0.001%~0.050%, with the remainder being Fe and unavoidable impurities. Through optimized C-Si-Mn-Cr-Nb-Ni composition system design, combined with controlled rolling and staged laminar flow cooling processes, a multiphase microstructure composed of ferrite and martensite was successfully obtained in the hot-rolled pickled duplex steel. This multiphase microstructure enables hot-rolled and pickled duplex steel to maintain high strength while retaining high elongation. Furthermore, a specific component ratio effectively suppresses softening in the weld heat-affected zone. This hot-rolled and pickled duplex steel is particularly suitable for passenger car chassis manufacturing, achieving a balance between lightweight design, high safety performance, and good manufacturability.

The invention relates to the technical field of shaft steel smelting, in particular to high-hardenability shaft steel and a production process thereof. The high-hardenability shaft steel comprises the following chemical components in percentage by mass: 0.38%-0.45% of C, 0.15%-0.35% of Si, 0.75%-1.00% of Mn, 0.90%-1.20% of Cr, 0.30%-0.60% of Ni, 0.15%-0.30% of Mo, 0.03%-0.08% of V, less than or equal to 0.015% of P, less than or equal to 0.010% of S, 0.015%-0.035% of Al, less than or equal to 0.0012% of O, less than or equal to 0.004% of N, less than or equal to 0.00015% of H and the balance of Fe and inevitable impurities during smelting. The shaft steel material with excellent hardenability is developed through component design and a reasonable smelting and continuous casting process in combination with a corresponding rolling technology.

The application relates to the technical field of alloy steel, in particular to a 90 ksi steel grade alloy steel for extra-high voltage wellhead equipment and a preparation method thereof. The raw material components of the alloy steel include, by mass percentage, C: 0.25-0.35%, Si: 0.15-0.35%, Mn: 0.40-0.90%, P<=0.020%, S<=0.010%, Cr: 1.90-2.50%, Ni<=0.10%, Mo: 1.00-1.50%, V: 0.01-0.10%, Nb: 0.01-0.10%, Al: 0.01-0.10%, B: 30-60 ppm, and the rest is Fe and inevitable impurities. The 90 ksi steel grade alloy steel for extra-high voltage wellhead equipment provided by the application has high strength and good hydrogen sulfide corrosion resistance as a wellhead forging material.

The invention relates to steel for a torsion beam and a preparation method of the steel. The steel comprises the following chemical components: 0.05 to 0.08 percent of C, less than or equal to 0.15 percent of Si, 1.2 to 1.7 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.003 percent of S, 0.01 to 0.05 percent of Nb, 0.03 to 0.08 percent of Ti, 0.1 to 0.4 percent of Cr, 0.1 to 0.25 percent of Mo, 0.01 to 0.04 percent of V, 0.0005 to 0.005 percent of Ca and the balance of Fe. [Ti] / [Mo] < = 0.6, and [Cr] + [Mo] = 0.2-0.5%; the microstructure of the steel for the torsion beam comprises ferrite and bainite. The steel for the torsion beam has the advantages that the tensile strength is larger than or equal to 650 MPa, the hole expansion rate lambda is larger than or equal to 85%, and the ductility A80 is larger than or equal to 24%.

The invention belongs to the technical field of fastening connection, and particularly relates to corrosion-resistant steel with the grade of 10.9 or above, a duct piece bolt and a preparation method of the duct piece bolt. By compounding Cu and Ni, a compact and stable rust layer is promoted to be formed on the surface of the material, further corrosion is prevented, and the corrosion resistance of the material is improved; through trace Sn, a compound of SnO2 and graphite can be formed on the surface of the material to serve as an anti-corrosion layer, and the corrosion resistance of the material is greatly enhanced; by optimizing the content of C and adding a trace amount of B, the hardenability of the steel is improved so as to meet the performance requirements of the large-specification duct piece bolt of the tunnel. According to the corrosion-resistant steel with the grade of 10.9 or above, specific elements with specific contents are adopted, the excellent corrosion resistance is achieved, the mechanical performance is good, and the comprehensive performance is excellent.

The invention discloses a production and manufacturing method based on an F22 horizontal Christmas tree for deep sea, and relates to the field of production and manufacturing of Christmas trees, the production and manufacturing method comprises the following operation steps: S1, billet selection: billet materials comprise C; mn; p; s; si; cr; ni; mo; cu; as; sn; sb; v; a gas element H; a gas element O; a gas element N; fE; impurity elements; s2, cogging and forging; s3, pre-heat treatment; and S4, heat treatment. According to the production and manufacturing method based on the F22 horizontal Christmas tree for deep sea, through anvil block preheating and temperature control in each step in the forging process, the internal and external temperature difference of the forge piece is delayed, so that the cracking tendency of the forge piece is reduced, and no obvious forging crack is generated on the surface of the forge piece; it is guaranteed that the finish forging temperature is larger than or equal to 850 DEG C, the method has the advantages that the forging ratio is increased, grains are refined, and UT detection is free of defects, the surface of a horizontal Christmas tree body produced through the technology is free of cracking, the forged piece dissection after heat treatment meets the NACE standard, and the grain size grade is larger than 8 grade.

The invention discloses a rolling and cooling process for Nb-containing medium-carbon hub bearing steel, which relates to the technical field of steel production and sequentially comprises the following procedures of heating, rough rolling, continuous rolling, temperature holding, pre-finish rolling, finish rolling and cooling. Wherein in the heating process, the continuous casting billet comprises the following chemical components in percentage by mass: 0.53 to 0.58 percent of C, 0.20 to 0.35 percent of Si, 0.75 to 0.90 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.005 percent of S, 0.20 to 0.35 percent of Cr, 0.05 to 0.050 percent of Al, 0.10 to 0.20 percent of Nb and the balance of matrix Fe and inevitable impurities. According to the controlled rolling cooling process of the Nb-containing medium-carbon hub bearing steel, the actual hot rolling grain size of finished round steel is larger than or equal to 5 grades, the austenite grain size is larger than or equal to 8.0 grades, and the hot rolling state hardness is smaller than or equal to 235 HB.