13results about How to "Improve hardenability" patented technology

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.

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.

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.

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 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 application relates to the technical field of welding materials, in particular to a continuous oil pipe butt welding gas protection solid core welding wire and a welding method; the chemical components of the solid core welding wire include the following: C: 0.08%-0.14%, Si: 0.2%-0.3%, Mn: 0.7%-1.0%, Ni: 0.15%-0.25%, Cu: 0.25%-0.35%, Cr: 0.5%-0.7%, Mo: 0.10%-0.15%, Nb: 0.02%-0.03%, Ti: 0.01%-0.02%, and the rest is Fe and inevitable impurities; by adopting low-carbon components, the fatigue performance of a weld is reduced, then the Mn, Ni, Mo, Cr and Cu systems are adopted, and i and Nb trace elements are added at the same time, so that the solid solution strengthening, fine-grain strengthening and precipitation strengthening methods can be comprehensively utilized to improve the strength of the weld, the hardenability of the weld metal is improved, the generation of bainite is promoted, the toughness and strength of the metal weld are improved, and therefore the fatigue resistance of a pipe-pipe butt welding joint is comprehensively improved.

The application provides a rare earth-titanium-boron composite vacuum seal welding high-density cored wire and a preparation method thereof, and belongs to the technical field of metallurgical auxiliary materials. The preparation method comprises the following steps: weighing lanthanum-cerium rare earth alloy powder, titanium powder and boron powder for batching, and then uniformly mixing under a protective atmosphere to obtain mixed powder; filling the mixed powder into a low-carbon steel cylinder after pretreatment under a protective atmosphere, and then preliminarily sealing to obtain a composite blank; performing a reduction reaction on the composite blank in hydrogen, and then performing seal welding under a vacuum condition to obtain a composite blank after vacuum seal welding; heating the composite blank after vacuum seal welding, and then performing hot drawing to obtain the cored wire. The cored wire provided by the application realizes stable composite addition of rare earth, titanium and boron with high recovery rate, and significantly improves the structure and performance of 20Mn2 steel and the like, and solves the problems of cold heading cracking, insufficient toughness and aging embrittlement.

This disclosure provides a steel sheet with excellent hardenability and excellent cold workability. The steel sheet disclosed herein has the following composition by mass %: C: 0.15~0.50%, Si: 0.01~0.50%, Mn: 0.20~1.30%, P: less than 0.100%, S: less than 0.100%, Al: less than 0.100%, Cr: 0.01~1.20%, N: less than 0.0150%, and the balance being Fe and impurities. The total surface area of ​​ferrite and cementite particles is 95% or more, the average grain size of ferrite is 5.0~20.0 μm, and the Cr concentration in the cementite particles is [Cr]. θ and Mo concentration [Mo] θ To satisfy equation (1), the average particle size of the cementite particles is less than 1.50 μm, the spheroidization rate of the cementite particles is greater than 70% and less than 85%, and the dispersion DI of the number of cementite particles in a small square partition with a side length of 10 μm, as defined by equation (2), is less than 45%. 2[Cr] θ +3[Mo] θ ≤3 / √C (1) DI=σ θ / N θ ×100 (2)

This invention belongs to the field of casting technology and mainly relates to a production method for thick-walled cast steel parts, including the following steps: design of the chemical composition of the cast steel parts; design of the heat treatment process: the cast steel parts are treated with a heat treatment method of high-temperature annealing + quenching + high-temperature tempering in sequence. By adjusting the content of a wide range of constituent elements required by the customer, and adding trace elements Nb and B strengthening elements when designing and optimizing the internal control composition, the hardenability of the cast steel material is significantly improved; and combined with the heat treatment process of high-temperature annealing + quenching + high-temperature tempering, the relevant parameter ranges and steps of each heat treatment process are designed reasonably to ensure that the entire cross-section of the cast steel part obtains a uniform tempered sorbite structure, and that the strength, plasticity, and average Akv of the surface, half radius, and core of the cast steel part all meet the standard requirements; the performance compliance rate of the finally obtained cast steel parts is 100%.

This application relates to a wire rod, an arc-sprayed wire, and a preparation method thereof, belonging to the technical field of arc-sprayed materials. The chemical composition of the wire rod, by mass fraction, is: C: 0.08%~0.14%, Si: 0.10%~0.60%, Mn: 1.50%~2.00%, P≤0.020%, S≤0.020%, Cr≤0.10%, Ni≤0.10%, Mo≤0.05%, Cu≤0.10%, Ti≤0.010%, Al≤0.020%, N≤0.010%, TO≤0.010%, with the remainder being Fe and unavoidable impurities. The wire is prepared by optimizing the chemical composition of the alloy wire rod through processes such as smelting, continuous casting, rolling, surface treatment, rough drawing, copper plating, and fine drawing. The mass fraction of Cu is 0.10%~0.25%, and the other elements are the same as those in the wire rod. This wire material has excellent wear and corrosion resistance and adhesion strength to the aluminum alloy substrate. It can form a stable protective coating on the inner wall of the engine cylinder, taking into account both the advantages of engine lightweighting and high performance requirements, and effectively supporting long-term service.

This disclosure provides a steel sheet with excellent hardenability and excellent cold workability. The steel sheet disclosed herein has the following composition by mass %: C: 0.15~0.50%, Si: 0.01~0.50%, Mn: 0.20~1.30%, P: less than 0.100%, S: less than 0.100%, Al: less than 0.100%, Cr: 0.01~1.20%, N: less than 0.0150%, and the balance being Fe and impurities. The total surface area of ​​ferrite and cementite particles is 95% or more, the average grain size of ferrite is 5.0~20.0 μm, and the Cr concentration in the cementite particles is [Cr]. θ and Mo concentration [Mo] θ To satisfy equation (1), the average particle size of the cementite particles is less than 1.50 μm, the sphericity of the cementite particles is greater than 85%, and the dispersion DI of the number of cementite particles in a small square partition with a side length of 10 μm, as defined by equation (2), is less than 45%. 2[Cr] θ +3[Mo] θ ≤3 / √C (1) DI=σ θ / N θ ×100 (2)

This application relates to an 1180MPa grade ultra-high strength steel and its preparation method, belonging to the field of steel manufacturing technology. The chemical composition of the ultra-high strength steel, by mass fraction, is: C: 0.04%~0.25%, Si: 0.60%~1.80%, Mn: 1.20%~3.00%, Al: 0.02%~0.10%, P≤0.005%, S≤0.002%, Ti: 0.010%~0.040%, Cr: 0.10%~0.80%, N≤0.004%, B: 0.0010%~0.0030%, with the remainder being Fe and unavoidable impurities. The microstructure of the ultra-high strength steel includes ferrite and martensite. A breakthrough in the performance of ultra-high strength steel is achieved by employing a C-Si-Mn-Cr-B composition system and a segmented cooling process. After finishing rolling, the slab is air-cooled under a temperature-controlled insulation hood, allowing it to enter the water-cooling stage within the phase transformation temperature range and complete the martensitic phase transformation at an ultra-high cooling rate. The resulting ultra-high-strength steel possesses both ultra-high strength and good ductility, while its elongation, cold bending performance, and sheet shape quality are all comprehensively improved. This method effectively overcomes the sheet shape defects, performance fluctuations, and weld softening problems of traditional methods, and is suitable for the industrial production of ultra-thin ultra-high-strength steel.

This invention relates to a method for preparing a metal crusher guard plate, comprising a substrate and a wear-resistant plate layer; the wear-resistant plate layer is attached to one side of the substrate, and the substrate and the wear-resistant plate are metallurgically bonded; the composition of the substrate by weight percentage is: C: 0.40~0.45%, Si: 0.15~0.30%, Mn: 0.60~0.75%, Cr: 0.20~0.45%, Mo: 0.10~0.25%, Cu: 0.15~0.25%, with the balance being Fe; the composition of the wear-resistant plate layer by weight percentage is: C: 3.5~4.5%, Si: 1.8~2.2%. The composition of the wear-resistant plate is as follows: Mn: 0.4~0.5%, Mo: 0.15~0.35%, Cr: 0.25~0.50%, Cu: 0.12~0.20%, Mg: 0.02~0.1%, W: 0.02~0.1%, N: 0.005~0.02%, WC: 0.5~0.1%, with the balance being Fe. The preparation process of the wear-resistant plate includes the manufacturing of sand cores and sand molds, the preparation of molten steel for the base material and molten iron for the wear-resistant plate layer, casting and molding, and heat treatment. The wear-resistant plate layer has high hardness and wear resistance, and contains hard particles of tungsten carbide, thereby improving the wear resistance of the wear-resistant plate and extending its service life.