126results about How to "Prevent decarbonization" patented technology

The invention discloses a cold drawing welded tube manufacture process for a high-accuracy hydraulic oil cylinder, which sequentially comprises the following steps of longitudinal shearing, roll bending molding, high frequency welding, welding joint treatment, online eddy current testing, sizing cutting, normalization, pinching, surface treatment, cold drawing, annealing, straightening, defect detection and cutting for measurement. The method is quick in processing molding, high in production volume, free of damage on surfaces in cold drawing and high in manufacture accuracy. After cold drawing, bearing capacity of a welded tube is improved by about 60%, and the welded tube is high in tensile strength and good in elongation rate. Follow-up gold processing amount is reduced, utilization rate of steel materials is improved, and manufacture cost is reduced. The cold drawing welded tube can be directly applied to manufacture of high-accuracy hydraulic oil cylinders.

The invention discloses an automobile transmission gear heat treatment method. The method includes the steps of carburization, carbonitriding, quenching, cleaning, low temperature tempering and air cooling. The carburization technique is combined with the carbonitriding technique, abrasion resistance, fatigue strength and corrosive resistance are improved by a layer of highly hard nitride layer obtained on the carburized layer on the surface of a gear, and comprehensive performance of a product is good; meanwhile, the problems of massive carbide appearing under the high carbon potential state and network carbide appearing in the cooling process are avoided, and early-age cracking of the surface of the gear is avoided; moreover, by the method, the technological process is simplified, heating and cooling links and discharge links are reduced, carburization deformation and quenching deformation are reduced, generation of black structures is reduced as well, and anti-fatigue performance is guaranteed; finally, by the method, production cycle is shortened greatly, energy consumption is lowered, and production efficiency is improved highly.

The invention provides a one-step forging and molding method of a steering knuckle of a heavy-duty car. The technical scheme provided by the invention is as follows: a warm forging process is adopted and the method successively comprises the following steps of: checking, baiting (a sawing machine), heating, roughly forging, extruding, pre-forging, carrying out finish forging, cutting edges and correcting, wherein in the heating step, a forging temperature rises in a range of 1100-1200 DEG C through heating and the temperature environment of the finish forging is in a range of 750-850 DEG C. Preferably, the forging temperature of the heating section is 1180 DEG C. Preferably, the finish forging temperature is 800 DEG C. The one-step forging and molding method provided by the invention has the beneficial effects that: in a machining process, the method is energy-saving, fast in temperature-rising speed and high in automation degree; and in a forging process: the method has the advantages of fewer forging equipment, reduced investment, high automation degree, high efficiency, and capabilities of reducing the temperature reduction when a work piece runs in an equipment room, and ensuring the temperature of the finish forging, namely ensuring the machining precision of the work piece; and the production efficiency is high.

The invention provides an energy accumulator tank forging forming process which comprises the step of carrying out primary extrusion, secondary extrusion and third time of extrusion on a bar stock in sequence to form a goblet blank finished product with one end opened and the other end closed, wherein a step is arranged on the outer wall of the opened end of the goblet blank finished product; a boss is arranged on the inner end face of the closed end; a blind hole is formed in the outer end face of the closed end; the blind hole is opposite to the boss. Compared with the prior art, the energy accumulator tank forging forming process is simple in working procedure and high in material utilization rate, and has the advantages of reducing the production cost, preventing the parts from decarburization, improving the strength of the parts and improving the production efficiency.

The invention relates to a high-calcium magnesite-dolomite carbon brick and a method for making the same. The invention adopts a technical proposal that the high-calcium magnesite-dolomite carbon brick is made from the following raw materials by weight percentage: 40 to 60 percent of 1 to 5mm calcium magnesite clinker, 5 to 15 percent of less than or equal to 1mm calcium magnesite clinker, 1 to 15 percent of less than or equal to 1mm magnesite clinker, 20 to 30 percent of less than or equal to 0.088mm magnesite powder, 2 to 8 percent of graphite, 0.5 to 3 percent of less than or equal to 0.088mm aluminum powder, 0.5 to 3 percent of less than or equal to 0.088mm silicon powder, 0.5 to 3 percent of less than or equal to 0.088mm silicon carbide powder and 3 to 6 percent of phenolic resin. The method comprises: mixing the raw materials uniformly according to a mixture ratio and pressing the well mixed raw materials into green bricks; keeping the green bricks at 220 DEG C for 4 to 7 hours and drying the green bricks for more than 20 hours totally; and performing hydration-proof treatment to the green bricks after the green bricks are moved out of a drying kiln. The brick is alkaline and can overcome the defects of molten steel pollution and unstable service life.

The invention discloses a spheroidizing annealing furnace for a steel wire. The spheroidizing annealing furnace comprises a furnace body, an inner cylinder and a furnace cover, wherein a coal gas heating point is arranged on the furnace body; a fan is arranged in the inner cylinder; a motor for driving the fan is arranged below the furnace body; a shaft barrel at the bottom of the inner cylinder extends out of the furnace body; and a rotating shaft for connecting the motor with the fan penetrates through the shaft barrel. In the production process for a long time, heat insulating cotton and refractory bricks are aged; waste gas in a combustion chamber is exhausted out of the furnace body from the outer wall of the shaft barrel without entering the inner cylinder; and the steel wire is positioned in the annealing furnace and methanol gas is introduced into the annealing furnace at high temperature, so that the decarburization of the steel wire is prevented and the annealing quality of the steel wire is improved.

The invention relates to the technical field of machine part machining, in particular to an automobile hub bolt and a machining technology of the automobile hub bolt. The machining technology of the automobile hub bolt comprises the following technology steps of cold heading, heat treatment, tooth rolling, blacking and dehydrogenation. The automobile hub bolt comprises a lock head and a lock pillar, wherein the lock head and the lock pillar are integrally formed. Threads are formed on the outer surface of the lock pillar, and a positioning shaft shoulder is arranged between the lock pillar and the lock head. A notch is formed in the positioning shaft shoulder. According to the automobile hub bolt machining technology, heat treatment is performed at first, and the treatment of tooth rolling is then performed, metal flow lines of the threaded portion of a product and continuity of uniform organizations after the heat treatment can be better protected, and the adverse risks of decarburization, recarburization, cracking and the like of the product can be obviously prevented. The automobile hub bolt is high in strength, good in safety performance of use and capable of effectively reducing safety risks and danger of an automobile.

The invention discloses a preparation method of high-quality 40Cr alloy structure straight-bar round steel. The preparation method includes the following steps, namely, the step A of molten iron pretreatment and desulfuration, the step B of molten iron smelting, the step C of deoxidization alloying, the step D of molten iron LF furnace refining, the step E of molten iron VD furnace vacuum refining, the step F of molten iron casting, the step G of steel billet heating, the step H of rolling and the step I of steel finishing. The high-quality 40Cr alloy structure straight-bar round steel produced through the method is high in cleanliness and low in inclusion content and content of harmful elements P and S, has high strength, excellent ductility and toughness, excellent impact toughness and excellent upsetting deformation capacity, and can well meet the requirements of the field of high-end machine manufacturing industries.

The invention discloses a manufacture method of a 50CrVA alloy structural steel type hot rolled round steel bar. The manufacture method comprises the following steps of: smelting by a converter; refining through an LF furnace; performing continuous casting on a quadrate billet; heating a steel billet; rolling a bar; and cooling in heap, thus obtaining a 50CrVA alloy structural round steel bar ofat phi 60mm, wherein the 50CrVA alloy structural round steel bar ofat phi 60mm has stable quality and outstanding mechanical process performance. According to the manufacture method, the traditional mode of smelting by a large ultra-high-power electric furnace is replaced by the mode of smelting through the converter and refining through the LF furnace during steel-making, so that the manufacture method has the characteristics that the quality is stable, the production cost is low, and little electricity consumption is caused; the processes of smelting by the converter, refining through the LF furnace, fast rolling at a low temperature, and cooling in heap are innovated to produce the 50CrVA alloy structural round steel which has stable quality and outstanding comprehensive performance; the 50CrVA alloy structural round steel can particularly be used as the material for a through shaft and a half shaft of a cargo truck; and compared with the prior art, the manufacture method has the advantages that the production cost can be reduced by more than 50** Yuan per ton of materials, so that the economic benefit is remarkable.

The invention provides high-strength bolt steel with excellent delayed fracture resistance and a preparation method thereof. The high-strength bolt steel comprises the following components in percentage by weight: 0.35-0.50% of carbon, 0.20-0.70% of manganese, 0.75-1.35% of chromium, 0.55-1.45% of molybdenum, 0.10-0.50% of vanadium, 0.005-0.10% of aluminum, 0-0.005% of sulfur, 0.02-0.05% of silicon, 0.005-0.15% of titanium, 0.0005-0.003% of oxygen, 0.001-0.007% of nitrogen, and the balance iron and other inevitable impurities; the content of titanium is not less than 3.5 times of the content of nitrogen; the sum of the contents of chromium, molybdenum and vanadium is not lower than 1.75%; and the sum of the contents of sulfur, oxygen and nitrogen is not higher than 0.01%. The high-strength bolt steel is high in purity and refined in grains, can be used for manufacturing high-strength bolts with tensile strength not lower than 1400MPa, has a section shrinkage rate not lower than 50%, is excellent in delayed fracture resistance, and can be applied to automobiles and mechanical parts.

The invention discloses a sintering furnace for powder metallurgy products. The sintering furnace is composed of a sintering furnace feeding section 1, a sintering furnace sintering section 2, a sintering furnace cooling section 3 and a bracket 4. The sintering furnace for powder metallurgy products has the advantages of simple structure and small occupation space and is convenient to operate. Because carbinol is used for replacing liquid ammonia, the sintering furnace generates no pollution and no harm to a human body and is safe and reliable to use. The sintering furnace has the functions of protecting metallurgy sintering products, preventing products from being oxidized, preventing the products from decarbonising and has carburization effect on the products, and generated H2O can reduce the products in the sintering process.

The invention provides an annealing furnace which comprises a furnace shell, a hearth, a furnace door, heating elements, a temperature thermocouple and an intelligent temperature controller. The annealing furnace is characterized in that the furnace door is of a side opening type structure and is arranged on a panel of the furnace shell through multiple sets of hinges, the hearth is closed and is provided with a furnace opening, a protruding block matched with the furnace opening is arranged on the furnace door, and the protruding block tightly presses and is tightly attached to the interior of the furnace opening; a handle is arranged on the furnace door, the position between the furnace shell and the hearth is filled with a thermal insulation layer, and the heating elements surround the four walls of the hearth; a containing support and a rail are arranged inside the annealing furnace, and therefore materials can be continuously pushed into and ejected out of the annealing furnace, the automatic degree is high, and the labor amount is reduced; and the temperature in the hearth is even, the machining efficiency is greatly improved, and the energy resource using rate can be effectively improved.

The invention provides an anti-shedding carbon nano paint and a preparation method thereof. The paint is composed of the following components in percentage by weight: 5 to 20 wt% of nano Al2O3, 50 to 80 wt% of diatomite, 2 to 10 wt% of graphite powder, 5 to 20 wt% of binder, 1 to 3 wt% of suspended dispersing agent, and the balance being solvent and impurities. The preparation method comprises the following steps: preparing an Al(NO3)3 water solution and a NH4HCO3 water solution from Al(NO3)3 and NH4HCO3 respectively; adding the Al(NO3)3 water solution into turbid liquid of diatomite and NH4HCO3, filtering and washing generated Al(OH)3 precipitate to obtain a mixture of nano Al(OH)3 and diatomite; heating to dehydrate the mixture to form nano Al2O3; adding a solvent, graphite powder, binder and a suspended dispersing agent into the mixture of nano Al2O3 and diatomite, and evenly mixing to obtain the nano level anti-shedding carbon slurry. The provided paint has the advantages that the size of nano particles is uniform, the size is small, the dispersibility is good, the cost is low, the preparation and painting technologies are simple and feasible, the natural peeling ability is strong, the high temperature oxidation and decarbonization of steel plate can be effectively avoided, and the paint is suitable for precision machining of metal workpiece with complicated shapes.

The invention discloses steel flat for high-performance farm tools and working tools and a processing method of the steel flat. The steel flat is composed of the following components in percentage by weight: 0.43-0.47 wt% of C, 0.18-0.30 wt% of Si, 0.60-0.75 wt% of Mn, not larger than 0.025 wt% of S, not larger than 0.025 wt% of P, and the balance of Fe and inevitable impurities. The steel flat is prepared by the procedures of molten steel smelting and deoxidation alloying, molten steel LF furnace refining, molten steel casting, billet heating, rolling and steel finishing. The 90mm*16mm steel flat for hoe and shovel tools is obtained by the processing method disclosed by the invention, the mechanical processing property of the steel flat is better than that of GB/T699 standard, and the section of the steel flat is rectangular. Compared with 45 steel for hoe and shovel tools produced by a complete continuous-rolled bar rolling mill process, the steel flat disclosed by the invention has the advantages that the rolling cost is reduced by more than 20 Yuan/ton, and the steel flat has the advantages of low production cost, strong process adaptability and controllability, excellent comprehensive product performance and the like, thereby being capable of well meeting the requirements of city greening and farm production development.

The invention belongs to the technical field of armor plate production and particularly relates to an armor plate for a C-level securicar and a preparation method thereof. In the armor plate for the C-level securicar, the armor plate smelting chemical composition comprises the following components in percentage by weight: 0.22-0.24% of C, 0.12-0.20% of Si, 1.02-1.20% of Mn, less than or equal to 0.007% of P, less than or equal to 0.003% of S, 0.020-0.030% of Alt, 0.25-0.35% of Cr, 0.10-0.15% of Mo, 0.015-0.025% of Ti, less than or equal to 10ppm of [O], less than equal to 12ppm of [N], less than or equal to 2ppm of [H] and the balance of Fe and unavoidable impurities. The armor plate has excellent bulletproof property, relatively high purity and good shape and facilitates welding.

The invention relates to a preparation method of surface wear-resistant coating for nodular cast iron. The preparation method comprises the following steps: 1, performing aluminizing treatment on a nodular cast iron workpiece, and cooling to obtain an aluminized workpiece, wherein the aluminizing temperature is 780-850 DEG C and heat is preserved for 2-5h at the temperature; 2, performing high-temperature oxidation treatment to the aluminized workpiece obtained in the step 1, wherein the high-temperature oxidation temperature is 900-1000 DEG C and heat is preserved for 2-5h at the temperature.By the preparation method combining the aluminizing treatment and the high-temperature oxidation treatment, the problems that the bonding strength between a wear-resistant layer and a substrate is low and preparation of coating for a workpiece with relatively small volume and having an inner wall is difficult can be solved.

The invention provides protective paint for heat treatment of metal, which is characterized by being prepared from the following raw materials in parts by weight: 2-5 parts of W type ethyl cellulose resin, 5-10 parts of organobentonite paste having an organobentonite content of 20%, 10-15 parts of 11# frit, 10-12 parts of 04# frit, 5-13 parts of M-1 frit, 5-8 parts of industrial grade barium metaborate, 1-6 parts of 400-mesh mica powder, 5-8 parts of industrial grade rubellan iron oxide, 3-11 parts of industrial grade pigment and 20-50 parts of ethanol. In an environment of 900 DEG C, the paint can achieve favorable drying property and excellent physical and chemical properties through secondary film forming of the combined frit; and meanwhile, a coating formed by the paint also has favorable self-releasing property.

The invention discloses an anti-oxidation coating applied to high-temperature steel and a preparation method thereof, and belongs to the technical field of preparation of a high-temperature anti-oxidation coating. Based on the research of heat treatment of steel substrate, an anti-oxidation coating applied to high-temperature steel is developed. The anti-oxidation coating is especially suitable for long-term heat preservation process of carbon steel and silicon steel. The anti-oxidation coating applied to high-temperature steel is characterized in that: the coating comprises the following ingredients (by weight): an inorganic adhesive 30-50, bauxite 10-40, water 50-100, chromium oxide 3-5, magnesia 20-50, feldspar 20-50, industrial aluminum powder 0-10, and an auxiliary agent 1-2. The coating can be applied by the construction process such as spray coating, brush coating, roller coating and the like. The coating is applied on the surface of a workpiece to be heated and undergoes heat treatment with heating of the workpiece, thus effectively preventing high temperature oxidation of the workpiece during the heat treatment process.

The invention discloses a production method of an HRB500E fine-grain high-strength anti-seismic anti-corrosion reinforcing steel bar. The method comprises the following steps of converter smelting, deoxidizing alloying, LF refining, square billet continuous casting, steel billet heating, rolling and cooling in sequence to produce the fine-grain high-strength anti-seismic anti-corrosion reinforcing steel bar which is stable in quality, excellent in plasticity and toughness, greater than 1.27 in yield ratio and 11.5-12.0 in ferrite grain size. The Cr, V and Ni composite microalloying process is adopted, converter smelting and LF external refining are matched, the rolling technology for controlling the inner diameter and negative deviation of the reinforcing steel bar at low temperature is adopted, finishing is combined, formation and precipitation of a fine and dispersed microalloy carbon (nitrogen) compound second phase are promoted, the steel strength is improved, meanwhile, the plasticity and toughness are remarkably improved, mechanical connection is further facilitated, reasonable matching of high strength, obdurability, low strain timeliness, shock resistance and corrosion resistance of the reinforcing steel bar is achieved, and the method can be applied to the fields of main stream hydropower station flood discharge tunnel engineering, expressway road and bridge engineering and the like.

The invention discloses a hard alloy and a process for local laser coating of the hard alloy, belonging to the technical field of surface-hardening treatment of metal. The hard alloy comprises, by weight, 20 to 27% of Cr, 10 to 14% of W, 1.5 to 2.5% of C, 21 to 23% of Ni, 1% of Fe, 0.8 to 1% of Si, 1% of B and 1.5% of Re, with the balance being Co. The hard alloy is powdery and has a powder size of 40 to 200 [mu]m. The powdery alloy material used in the invention has good compatibility with a matrix material, the dilution rate of a cladding layer is small, and the thermal expansion coefficients of the two materials are almost same; through pretreatment and post-heat-treatment of a matrix and the cladding layer, temperature gradient is further reduced and internal thermal stress in the cladding layer is decreased, and thus, the phenomena of cracks and shedding of an alloy layer are avoided; therefore, the hard alloy overcomes the problem of infirm bonding between a coated alloy layer and matrix metal in the prior art and has the characteristics of high hardness and good wear resistance.