3962 results about "Tempering" patented technology

A 7XXX series aluminum alloy having reduced quench sensitivity suitable for use in aerospace structural components, such as integral wing spars, ribs, extrusions and forgings comprises, in weight %: 6 to 10 Zn, 1.3 to 1.9 Mg, 1.4 to 2.2 Cu, wherein Mg<=Cu+0.3, one or more of 0 to 0.4 Zr, up to 0.4 Sc, up to 0.2 Hf, up to 0.4 Cr, up to 1.0 Mn and the balance Al plus incidental additions including Si, Fe, Ti and the like plus impurities. By controlling the Mg content to 1.3 to 1.7 wt. %, limiting Mg<=Cu+0.3 and 6.5<=Zn<=8.5, the alloy provides significantly improved combined strength and fracture toughness in heavy gauges. For example, in a six-inch thick plate there is provided a combination of about 75 ksi quarter-plane tensile yield strength (L) with a fracture toughness (L-T) of about 33 ksi{square root}in which progresses by artificial aging/tempering to a combined strength and fracture toughness of about 67 ksi tensile yield strength (L) and a fracture toughness (L-T) of about 40 ksi{square root}in. The alloy product possesses equally attractive combinations of strength and fracture toughness when intentionally quenched slowly following solution heat treatment so as to lessen dimensional distortion, particularly in shapes of varying cross section.

The invention discloses low-yield ratio and high-strength steel for bridges and a manufacturing method thereof. The steel comprises the following chemical components by weight percent : 0.06-0.10 percent of C, 0.20-0.45 percent of Si, 1.20-1.50 percent of Mn, no more than 0.010 percent of P, no more than 0.0020 percent of S, 0.30-.060 percent of Ni, 0.20-0.50 percent of Cu, 0.15-0.50 percent of Mo, 0.025-0.060 percent of Nb, no more than 0.035 percent of Ti, 0.020-0.040 percent of Alt, and Fe and unavoidable impurities in balancing amount. According to the invention, through smelting, refining, performing a reasonable thermo-mechanical control process (TMCP) and optimizing tempering heat treatment production, the tensile strength of the steel is 700-780 MPa, the yield strength is 530-600MPa, the extensibility is greater than or equal to 18 percent, the yield ratio is less than or equal to 0.80, and 40 below zero DEG C low-temperature longitudinal impact is greater than or equal to 100 J, so that the steel is good in obdurability matching and low in the yield ratio, is provided with excellent performance of shock prevention, and is stable in production process and strong in operability.

The present invention discloses one kind of thick steel plate with high strength and low welding crack sensitivity and its production process. The chemical composition includes C 0.06-0.09 wt%, Si 0.15-0.55 wt%, Mn 1.00-1.60 wt%, P not more than 0.015 wt%, S not more than 0.006 wt%, Ni 0.15-0.40 wt%, Cr not more than 0.30 wt%, Mo not more than 0.30 wt%, Cu not more than 0.30 wt%, V 0.02-0.06 wt%, Nb 0.005-0.05 wt% and Als 0.010-0.04 wt%, except Fe and inevitable impurities; and meets Pcm not higher than 0.20 % and Ceq not higher than 0.42 %. The production process includes two stage controlled rolling, on-line laminar flow cooling, off-line tempering and other steps. The produced steel plate has thickness up to 75mm, tensile strength not lower than 610 MPa and very low welding crack sensitivity.

The present invention discloses one kind of thick steel plate with great line energy and low welding crack sensitivity and its production process. The chemical composition includes C 0.06-0.10 wt%, Si 0.15-0.40 wt%, Mn 1.20-1.60 wt%, P not more than 0.015 wt%, S not more than 0.007 wt%, Ni 0.15-0.40 wt%, Cr not more than 0.30 wt%, Mo 0.15-0.30 wt%, V 0.02-0.06 wt%, Al 0.015-0.045 wt%, Ti 0.010-0.034 wt%, except Fe and inevitable impurities; and meets Pcm not higher than 0.20 %. The production process includes pre-treatment of molten iron, smelting in converter, LF furnace plus VD furnace vacuum treatment, two stage controlled rolling, on-line laminar flow cooling, tempering at 600-680 deg.c and other steps. The produced steel plate has no need of quenching and tempering treatment.

The invention discloses a boron-contained centrifugal composite high-speed steel roller, which comprises an outer layer of the high-speed steel roller, a middle layer of the high-speed steel roller and a core of the high-speed steel roller. The manufacturing method includes steps of smelting, interrupted front treatment, roller pouring, annealing, rough machining, double tempering, finish machining and testing. By the method, three-layer composite roller technology is adopted in the boron-contained centrifugal composite high-speed steel roller, composite ability of the outer layer of the high-speed steel roller and the core of the high-speed steel roller is increased, the roller is less prone to spalling, high in rigidity and accident resistant ability, fine in abrasion resistance, safe in use, low in energy consumption and short in cycle in heat treatment, oxidation and decarburization of the roller and roller breakage in use are avoided. The manufacturing method is simple and hot quenching process is omitted.

The invention provides a heat treatment method for high-strength and toughness hot-formed steel plates for automobiles, which belongs to the technical field of high-strength steels for automobiles, and aims to solve the problems of high strength but poor plasticity of steel plates for hot-formation at present. Technical measures to solve the problem: the mass percentage of the components is: C: 0.2~0.4%, Si: 0.1-0.5%, Mn: 1.0~2.0%, Cr: 0.1~0.5%, B: 0.001-0.005%, Ti : 0.01~0.05%, Al: 0.01-0.1%, P: <0.02%, S: <0.01%, N: <0.01%, and the balance is iron and unavoidable impurities. In the range of ~500℃, tempering treatment is carried out for 1-5min. The invention has the advantages that after the tempering treatment, the plasticity of the hot-formed steel is significantly improved while the strength is slightly reduced, and the toughness of the steel plate after hot stamping is improved.

The invention relates to a high-strength variable cross-section reed which can bear high-stress, comprising the components with mass mixture ratios as follows: 0.46 to0.62 percent of C, 0.20 to 2.00 percent of Si, 0.30 to 0.90 percent of Mn, 0.8 to 1.20 percent of Cr, 0.10 to 0.20 percent of V, 0.005 to 0.1 percent of Al, and the rest of Fe and impurity. The manufacturing method of the reed is that: temperature control and variable cross-section rolling is carried out to a spring flat steel which has the components and mass mixture ratios under 700 DEG C to 950 DEG C to form the variable cross-section reed which is then heated to 86 DEG C to 950 DEG C for quenching, tempering is carried out at temperature of 380 DEG C to 450 DEG C, and then stress shot blasting is carried out to the pulled stress surface by adopting the steel shot with diameter from 0.8 mm to1.0 mm at the speed of 50 to 90mm/s under the bending stress of 800MPa to 1600MPa. The high-strength variable cross-section reed effectively solves the problem that fatigue property on the surface and the inside defect sensibility is significantly increased under the high stress condition after the strength is improved, the tensile strength is more than1800MPa, and the performance thereof is much better than the performance level of domestic spring and achieves the international leading level.

The present invention relates to one kind of cast steel for bearing parts in mechanical lifting system and its making process. The cast steel of Cr-Ni-Mo line consists of C 0.15-0.30 wt%, Mn 0.60-1.10 wt%, Si 0.3-0.8 wt%, Ni 0.4-1.1 wt%, Cr 0.4-1.1 wt%, Mo 0.15-0.40 wt%, S less than 0.025 wt%, P less than 0.025 wt%, and residual elements including Cu, W and V less than 0.60 wt%. The making process of the cast steel includes the following technological steps: making steel in MF furnace or electric arc furnace; casting in sand mold with equivalent circular kiel test rod; normalizing, quenching and tempering of both cast part and test rod in the same furnace; and non-destructive detection of the cast part.

The invention discloses an abrasion-resistance high-speed steel composite roller and a preparation method thereof, and belongs to the technical field of rollers. The composite roller forms a whole through roller body high-speed steel and roller core nodular cast iron by means of centrifuge composite casting. The roller body molten steel is controlled to comprise, by mass, 1.5%-2.4% of C, 3.5%-6.0% of Cr, 3.5%-6.0% of Mo, 3.5%-6.0% of V, 1.5%-3.5% of W, 0.6%-1.2% of Nb, 0.5%-1.2% of Ni, 0.3%-0.8% of Si, 0.3%-0.8% of Mn, 0-0.04% of S, 0-0.04% of P and the balance Fe. The roller body molten steel is deoxidized, external-furnace modification treatment is conducted on the molten steel through multi-element micro-alloy wires, and then pouring is conducted on a centrifugal machine to form the roller; the roller core is made of nodular cast iron, tempering is conducted on the roller after quenching, and therefore the characteristics of being high in hardness, high in toughness, good in abrasive resistance and the like are realized, and an excellent using effect is achieved.

The invention discloses a hypoeutectic high-chromium white cast iron, which comprises the following components calculated according to mass fraction: 1.9-2.4 of C, 16-22 of Cr, less than or equal to 0.8 of Si, less than or equal to 0.7 of Mn, 0.5-1.0 of Ni, 1.0-1.7 of Mo, less than 0.04 of S, less than 0.06 of P, 0.05-0.4 of RE, 0.5-1.0 of Cu, 0.05-0.15 of Zn, 0.1-0.3 of V and the balance of Fe. The preparation method comprises the following steps of: defining the mixture ratio according to the requirement of mass fraction and mixing; mixing scrap steel and pig iron in an intermediate-frequency induction furnace and heating the mixture to be melt; after molten iron is smelt, sequentially adding high carbon ferro-chrome, manganese iron, nickel and molybdenum and smelting again; feeding a zinc ingot with small granularity and rare earth or vanadium at the bottom of a casting ladle, covering a steel sheet or scrap iron and compacting; pouring the molten iron into the casting ladle and carrying out metamorphism and deslagging treatment; casting the molten iron and forming to obtain a hypoeutectic high-chromium white cast iron piece; then placing the hypoeutectic high-chromium white cast iron piece into a heat treatment furnace for thermally treating; and quenching and tempering to obtain a hypoeutectic high-chromium white cast iron material with the hardness of 60-66HRC (Hardness Rockwell) and the impact ductility of 10-14J/cm<2>. The hypoeutectic high-chromium white cast iron has the advantages of low cost, high wear resistance and reliable use safety. In addition, the preparation method of the hypoeutectic high-chromium white cast iron is simpler, and is easy in operation and strong in practicability.

The invention relates to low-cost chromium-molybdenum-vanadium hotwork tool-die steel and a heat treatment process thereof and belongs to the technical field of alloy steel manufacturing processes. The steel comprises the following components by weight percent: 0.3-0.4% of C, 0.6-1.2% of Si, 0.6-1.2% of Mn, 3.5-4.5% of Cr, 0.8-1.2% of Mo, 0.4-0.8% of V, less than 0.02% of P, less than 0.02% of S and the balance of Fe. The preparation process of the hotwork tool-die steel is as follows: mixing, smelting, casting and then remelting electroslag; carrying out homogenization treatment at 1200-1280 DEG C for 8-10 hours, then forging, and carrying out ultrafining heat treatment and isothermal annealing treatment; and finally quenching and tempering, namely heating steel ingots to 1000-1100 DEG C to be austenitized and carrying out tempering two to three times at 560-620 DEG C after carrying out oil quenching or high pressure gas quenching. The hotwork tool-die steel has the advantages of high heat stability and roughness and good heat fatigue property.

The invention discloses a quenching and tempering method in tooth punching process of a gear with a medium-hard tooth surface. The method comprises the following steps of: machining of a gear blank: roughly turning and drilling the gear blank after forging and normalizing treatments; rough turning and heat treatment of a tooth shape: roughly hobbing the gear to form the tooth shape; releasing needed grinding amount according to a tooth thickness; then quenching and tempering at medium and high temperature, wherein the heating process of the quenching is under the protection of a carbon potential atmosphere; and carrying out shot blasting after the heat treatment; finish machining of the tooth shape: firstly, finely machining a tooth shape assembling standard of the gear by semi-finish turning and accurate grinding; and then finely machining the tooth shape of the gear by tooth grinding. The gear manufactured by the method disclosed by the invention has the advantages that the hardness of the tooth surface and the tooth root is improved, the hardness of the quenched and tempered tooth surface ranges from about HB340-370, thereby solving the problem that the medium-hard gear hobbing tool with tooth surface hardness higher than HB320 is difficult to machine. As a process of hobbing before the heat treatment is adopted in the method, the hobbing efficiency is greatly improved and the tool loss is reduced.

The invention relates to hot-work die steel for an extrusion wheel and a manufacturing method of the die steel. The invention adopts the technical scheme that the manufacturing method comprises the following steps: hot-forging after scrap steel or molten iron and scrap steel are smelted in an electric furnace and are subjected to electroslag remelting or vacuum induction melting and then carry out spheroidizing annealing at a temperature of 700-880 DEG C; quenching at a temperature of 1,020-1,120 DEG C and tempering at a temperature of 530-650 DEG C, wherein the hot-work die steel has a hardness of up to 40-52HRC and a tensile strength of up to 1,850-1,955MPa. The hot-work die steel comprises the following chemical components in percentage by weight: 0.30-0.50wt% of C, 0.80-1.20wt% of Si, 0.2-0.5wt% of Mn, 3.00-5.00wt% of Cr, 1.00-1.50wt% of Mo, 0.70-1.20wt% of V, 0.005-0.03wt% of N and less than 0.030wt% of P, less than 0.030wt% of S and the balances of Fe and inevitable impurities. The steel has the characteristics of low cost, good thermal fatigue property, high heat stability and excellent comprehensive property and can be used for manufacturing the extrusion wheel of a continuously-extrusion-molded coating machine and other hot-work dies.

The invention provides ultra-high strength steel with yield strength level of 1100MPa-1200MPa and a production method of the steel. The chemical constituents (weight percentage) include: 0.15-0.18% of C, 0.20-0.25% of Si, 0.85-1.25% of Mn, 0.20-0.60% of Cr; and 0.45-0.65% of Mo, 0.035-0.060% of V, 0.015-0.020% of Nb, 0-0. 55% of Ni, 0-0.035% of Cu, 0.01-0.06% of Al, no more than 0.015% of P, no more than 0.01% of S, no more than 0.008% of N, the balance of Fe and unavoidable impurities. The production method includes: smelting and casting into casting blank; and heating the casting blank to 1150-1250 DEG C, wherein the final rolling temperature is 860-920 DEG C, the coiling temperature is 650-750 DEG C, the quenching heating temperature is 880-930 DEG C, the thermal insulation time is 20-90min, the tempering heating temperature is 100-450 DEG C, the thermal insulation time is over 90min. Slow cooling or air cooling is conducted to room temperature. For the steel plate produced with the constituents and the technology, the yield strength is 1150-1230MPa, the tensile strength is 1250-1340MPa, the elongation is 11-13.5%, and the impact power value at minus 40 DEG C is 21-34J.