78results about How to "Improve hardness uniformity" patented technology

The invention discloses an economical non-quenched and non-tempered micro-alloyed plastic die steel plate and a making method thereof. The economical non-quenched and non-tempered micro-alloyed plastic die steel plate comprises 0.32-0.40wt% of C, 0.20-0.50wt% of Si, 1.00-1.50wt% of Mn, 1.20-1.70wt% of Cr, 0.20wt% or less of Mo, 0.0025wt% or less of B, 0.03wt% or less of Ti, 0.03wt% or less of Nb, and the balance Fe. The making method comprises the following steps: carrying out converter smelting, LF+RH refining and continuous slab casting; heating the obtained slab at 1200-1230DEG C, carrying out precision rolling at 900-950DEG C, and carrying out finishing rolling at 870-920DEG C; carrying out controlled cooling after the steel plate rolling; and tempering the steel plate obtained after the controlled rolling and controlled cooling at 550-600DEG C to obtain the finished pre-hardened plastic die steel plate having a bainite structure. The yield strength, the normal temperature impact toughness and the cross section hardness of the steel plate are above 800MPa, above 20J and 310-350HB respectively. The making method is suitable for the production of pre-hardened plastic die steel plates with the specification of below 120mm from 320mm continuous casting blanks.

The invention relates to high-performance hot-working die steel for a large die-casting die and a manufacturing technology of the high-performance hot-working die steel. The high-performance hot-working die steel is prepared from, by mass, 0.20%-0.30% of C, smaller than or equal to 0.40% of Si, 0.30%-0.60% of Mn, 4.10%-4.50% of Cr, 2.10%-2.30% of Mo, 0.10%-0.20% of W, 0.40%-0.80% of V, smaller than 0.01% of P, smaller than 0.005% of S, 0.02%-0.04% of Nb and the balance Fe. The manufacturing method of the die steel comprises the following manufacturing process that material mixing, smelting andcasting are conducted, and then electroslag remelting is conducted; high-temperature diffusion heat treatment is conducted, multi-directional forging hot working is conducted, and cooling controllingafter forging is conducted; secondary carbide refining heat treatment and isothermal annealing treatment are conducted; and finally quenching and tempering heat treatment is conducted. The hot-working die steel has the advantages that the hardenability, the heat stability, the impact toughness and the thermal fatigue property are superior to those of H13 steel, the hot-working die steel can be machined into a single large die-casting die with the weight reaching 5 tons or above, and the good using performance is achieved.

The invention relates to boron microalloyed die steel and a preparation process thereof and belongs to the technical field of alloy steel preparation processes. The main alloy elements in alloy chemical components of the die steel comprise, by mass, 0-0.20% of C, 0-0.20% of Si, 1.20-1.60 of Mn, 1.10-1.50% of Cr, 0-0.30% of Ni, 0.20-0.35% of Mo, 0-0.10% of V, less than 0.015% of P, less than 0.005% of S, 0.005-0.01% of B, and the balance Fe. The preparation process of the steel includes the following steps of conducting burdening, smelting, casting and hot delivery; conducting high temperature diffusion heat treatment, multi-directional forging hot working and post-forging hydrogen diffusion tempering treatment; and finally conducting quenching-and-tempering heat treatment so as to obtain a tempered martensite structure with the hardness being 32-38 HRC. The boron microalloyed die steel and the preparation process thereof have the advantages that the prepared die steel has low cost, high hardenability, high hardness, high polishing performance and high skin grain etching performance.

The invention discloses a high-strength steel thin-wall piece vacuum thermal treatment process, which comprises vacuum quenching and vacuum tempering, wherein the vacuum quenching comprises the following specific steps of: heating to 650 DEG C at the vacuum degree between 1.33*10<-4> Pa and 1.33*10<-2> Pa; preserving heat for 25 minutes; heating to 870-880 DEG C; preserving heat for 30-35 minutes; charging 7-9 bar of high-purity nitrogen gas into a furnace for performing air pressure quenching; and cooling to 50-60 DEG C; and vacuum tempering comprises the following specific steps of: performing counter-flow heating to a tempering temperature under the protection of 1-1.5 bar of high-purity nitrogen gas; preserving heat for 1.5-2 hours; charging 3-4 bar of high-purity nitrogen gas into the furnace for performing air pressure cooling; and cooling to a low temperature for discharging. A high-strength steel thin-wall piece vacuum thermal treatment surface has the advantages of freeness from oxidation and decarburization, high size precision, uniform hardness, high strength and low cost.

The invention relates to a prehardening plastic die steel plate and a manufacture method thereof. The steel plate comprises, by weight, C 0.28 to 0.40, Si 0.20 to 0.80, Mn 0.60 to 1.0, Cr 1.40 to 2.2, Mo 0.30 to 0.50, P no more than 0.030, S no more than 0.030, Al 0.01 to 0.08, Ti 0.01 to 0.05 and B 0.0010 to 0.0050, with the balance being Fe and unavoidable impurities. The manufacture method comprises a first step of smelting, that is, carrying out tapping and casting when components in liquid steel meet requirements so as to obtain steel ingots, a second step of hot rolling, that is, rolling the steel ingots into steel plates with a thickness of 60 to 200 mm, a width of 300 to 1500 and a length of 2000 to 8000 mm, a third step of cooling, that is, cooling the steel plates to a temperature below 550 DEG C, wherein, slow cooling time is no less than 24 hours, and a fourth step of tempering, that is, arranging the steel plates in a tempering furnace for tempering at a temperature of 400 to 600 DEG C, carrying out insulation for 4 to 12 hours, taking the steel plates out of the tempering furnace and cooling the steel plates to room temperature in the air. The difference of surface hardness of prehardening plastic die steel plates manufactured in the invention is within 20 HB.

The invention relates to a highly-polished prehardened die steel, and a preparation method thereof. The highly-polished prehardened die steel is composed of, by mass, 0.21 to 0.25% of C, Si<=0.30%, 1.40 to 2.00% of Mn, 1.30 to 1.70% of Cr, 0.60 to 1.00% of Ni, 0.40 to 0.60% of Mo, V<=0.10%, P<0.015%, S<0.005%, 0.02 to 0.04% of Nb, and the balance Fe. The preparation method comprises following steps: material blending, smelting, casting, and hot charging; high temperature diffusion heat treatment, multi-directional forging heat processing, after-forging heat treatment, and sawing; and hardeningand tempering heat treatment. The hardness of the obtained tempered martensite structure ranges from 38 to 42HRC. The advantages of the highly-polished prehardened die steel are that: cost is low, hardenability and hardness are high, and polishing properties and cleavage line etching performance are excellent.

The invention relates to high-uniformity and high-polishing type plastic mould steel ZW636 and a preparation method thereof. The plastic mould steel particularly comprises the following components inpercentage by mass: 0.20 to 0.30 percent of C, 0.10 to 0.40 percent of Si, 1.20 to 1.60 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.005 percent, 1.20 to 1.80 percent of Cr, 0.90 to 1.20 percent of Ni, 0.48 to 0.70 percent of Mo, 0.08 to 0.15 percent of V, 0.015 to 0.030 percent of Als, less than or equal to 0.25 percent of Cu, O of less than or equal to 12 ppm,N of 60 to 100 ppm, H of less than or equal to 1.5 ppm and the balance of Fe and unavoidable impurities. Through the specific preparation method, the plastic mould steel has the following characteristics: (1) the tissue is uniform, the grain crystal is small, the tissue rating is less than or equal to level 4, and the grain size is more than level 6; (2) the hardness is uniform and the hardness uniformity of the same section is less than or equal to 3 HRC; and (3) the high-uniformity and high-polishing type plastic mould steel ZW636 has high polishing property and can be polished to 8000 meshes, and the polishing rate is 95 percent.

The invention discloses steel for a high-strength, high-toughness and high-wear-resistance steel ball and a preparing method of the steel, and belongs to the technical field of steel for wear-resistant steel balls. The problems that the strength and toughness of existing steel for wear-resistant steel balls cannot meet requirements at the same time, and uniformity is poor are solved. The steel forthe wear-resistant steel ball comprises, by mass, 0.60-0.70% of C, 1.50-1.80% of Si, 0.92-1.2% of Mn, 1.30-2.00% of Cr, 0.01-0.20% of Mo, 0.25-0.60% of Ni, 0.01-0.05% of Al, 0.05-0.10% of Cu, 0.01-0.20% of V, less than or equal to 0.03% of S, 0.01-0.02% of P and the balance Fe and inevitable trace impurities, wherein the sum of Mo and V is greater than or equal to 0.08%. The preparing method includes the following steps of performing smelting to obtain molten steel, performing casting to obtain a cast ingot, forging the cast ingot to obtain a steel blank, and performing quenching and annealing treatment on the steel blank or quenching and partitioning treatment on the steel blank. The steel for the high-strength, high-toughness and high-wear-resistance steel ball is high in strength, toughness and uniformity and wide in application range.

The invention relates to a method for improving hardness uniformity of a cross section of a heat-treated steel rail head. The method comprises the following steps that the starting cooling temperatureof the heat-treated steel rail head is 740-820 DEG C, a dynamic staged accelerated cooling process is adopted, and the cooling speed and the cooling time of five cooling stages of the heat-treated steel rail head are sequentially as follows that the cooling speed is less than or equal to 9 DEG C/s, and cooling time is 8-12s; the cooling speed is less than or equal to 3 DEG C/s, and the cooling time is 3s; the cooling speed is less than or equal to 6 DEG C/s, and the cooling time is 30-40s; the cooling speed is less than or equal to 2 DEG C/s, and the cooling is carried out to 300-380 DEG C; and the natural cooling is carried out to room temperature. In the cooling stage, the cooling speed difference between adjacent stages is less than and equal to 6 DEG C/s. The cooling stage and the initial time of the heat-treated rail bottom are the same as those of the heat-treated rail head, and the cooling speed of each stage of the heat-treated rail bottom is 60-70% of that of the corresponding stage of the heat-treated rail head. The method is simple and high in operability, and the Rockwell hardness distribution uniformity of the cross section of the heat-treated steel rail head is remarkably improved.

The invention discloses a low-alloy composite roller and a manufacturing method of the low-alloy composite roller. The composite roller comprises an outer white cast iron layer and an inner grey castiron layer. The outer white cast iron layer is prepared from, by mass, 3.0-3.60% of C, 0.50-1.0% of Si, 0.50-1.0% of Mn, 0.50-1.50% of Cr, 0.50-1.50% of Ni, 0.20-1.0% of Mo, 0.10-0.80% of V, 0.10-0.30% of Ti, 0.10-0.30% of Ce, P with the content less than 0.15%, S with the content less than 0.10% and the balance Fe. The inner grey cast iron layer is prepared from, by mass, 3.0-3.5% of C, 1.5-2.5%of Si, 0.5-1.0% of Mn and the balance Fe. The toughness and hardness uniformity of the roller can be improved, the hardness of the composite roller is larger than 53HRC, and the wear resistance of theroller is effectively improved.

The invention relates to a copper-containing high-polishing pre-hardening plastic die steel and a manufacturing process thereof. The alloy chemical components of the die steel are mainly composed of the alloy elements of, in percentage by mass, less than or equal to 0.10% of C, less than or equal to 0.30% of Si, 0.20-0.40% of Mn, less than or equal to 0.30% of Cr, less than or equal to 0.20% of Mo, less than or equal to 0.10% of V, less than 0.015% of P, less than 0.005% of S, 1.60-2.00% of Ni, 0.40-0.70% of Al, 0.40-0.70% of Cu and the balance Fe; and the hot-work die steel is subjected to material preparing, smelting, casting, and then electroslag remelting; the die steel is subjected to high-temperature diffusion heat treatment, then multi-directional forging thermal processing and post-forging heat treatment; then the die steel is subjected to hydrogen diffusion annealing and pre-hardening treatment; and finally, the die steel is subjected to aging heat treatment. The die steel hasthe advantages that the hot-work die steel has the high polishing performance and the low alloy cost.

The invention discloses a calendaring roller shell and a manufacturing method of the calendaring roller shell. The calendaring roller shell is made of forged steel. The manufacturing method of the calendaring roller shell comprises the steps of roller blank preparation, thermal refining, surface quenching treatment, tempering treatment and final machining treatment. A line-frequency induction quenching method is adopted by surface quenching treatment. The quenching temperature is 890 DEG C-910 DEG C, the heating width of a line-frequency induction ring is 80mm-100mm, and the walking speed of the line-frequency induction ring is 0.8mm/s-1.2mm/s. According to the calendaring roller shell, cast iron is replaced by the forged steel and a special surface quenching technology is combined, so that the hardness of the surface of the finally machined calendaring roller shell reaches 82 HSD-88HSD, the uniformity of hardness is equal to or smaller than 3HSD, the depth of a surface quenching layer reaches 15mm-20mm, and the service life reaches over 20 years.

The invention realtes to a preprocessing technology for processing integral key shaft, accomplished by the following steps: induction annealing area of integral key shaft using electromagnetic induction to be heated to above A[C3] over 50-80 degree for incubation of 1-2 hours, namely slowly cooling to 300 degree in asbestos drum and then air colling to narmal temperature. The surface hardness can be greatly decreased by surface induction annealing treatment, at the same time the uniformity of hardness is increased and the grain can be refined (grain size 8), and the uniformity of structure can be advanced, therefore the processability of integral key shaft can be greatly improved, the process quality thereof can be advanced, the tool life is increased by more than 5 times, the processing cost is saved, and the production effciency and economy benefit can also be obviously generated. Compared with modulator procedure, the said technology saves proscessing cost and greatly increases production timeefficiency.

The invention relates to the welding processing field, disclosing a method for stirring a welding pool in the process of welding and an electromagnetic pendulum device. The method comprises the following steps: the electromagnetic pendulum device is installed at the position of a welding gun; after a electromagnetic coil power supply of the electromagnetic pendulum device is connected, the magnetic field with a certain direction is generated around a magnetic rod, under the action of the magnetic field, the electric arc generated by the welding gun oscillates and stirs the welding pool to ensure the evenness of metal impurities. The electromagnetic pendulum device comprises the electromagnetic coil, the magnetic rod and a magnetic pendulum shield; wherein, the electromagnetic coil winds the periphery of the magnetic rod, and the magnetic pendulum shield is arranged outside the electromagnetic coil. The method in the invention improves the uniformity of hardness of work pieces and ensures the quality of the surfacing layers on the surfaces of the work pieces, thus ensuring the qualification rate of repaired work pieces.

The invention relates to the field of steel for dies, in particular to high-toughness plastic die steel and a production method thereof. The die steel comprises the chemical components of, by mass, 0.55-0.75% of C, 2.00-3.50% of Mn, 0.45-0.50% of Mo, 2.00-3.00% of Cr, 0.40-0.60% of Sr, 0.80-1.20% of Ni, 0.02-0.04% of S, 0.20-0.30% of V, 0.004% of Ca and the balance Fe and unavoidable impurities. The production method comprises the following steps of plate blank heating, rolling, steel plate slow cooling, normalizing treatment and tempering heat treatment. By controlling rolling and the normalizing process, crystal particles are greatly refined, the hardness uniformity is high, the impact toughness is high, the free-cutting effect is obvious, the performance is stable, and the toughness ishigh.

The invention discloses a train wheel cooling device and method and a preparation method, and belongs to the technical field of train wheels. The device comprises a quenching table and a plurality ofspray guns which are uniformly arranged in the circumferential direction of the quenching table, and each spray gun comprises a water outlet panel and a water inlet branch pipe. Large and small spraying holes which are different in diameter are formed in the water outlet panels, wherein outlet water from the small spraying holes is separately controlled by a branch pipe, the large spray holes aredivided into the upper large spray holes and the lower large spray holes, and outlet water from the upper large spray holes and outlet water from the lower large spray holes are controlled by different branch pipes. According to the train wheel cooling device, the intensity of the cooling water jetted to the train wheels can be easily adjusted, and the uniformity of cooling, in the radial direction and in the axial direction, of wheel rims is improved. The cooling method is used for cooling of heat treatment of the train wheels by using the cooling device when the train wheels are prepared, the hardness uniformity of the wheel rims is effectively enhanced, and the using performance of the train wheels is improved. The preparation method is used for cooling of the heat treatment of the train wheels in the process of preparation using the cooling method, and the train wheels which are high in wheel rim hardness uniformity can be prepared.

The invention particularly relates to a medical grinding wheel for grinding insulin needles and a manufacturing method thereof. The medical grinding wheel for grinding the insulin needles is characterized in that raw material components of the medical grinding wheel include, by weight, 60-65% of silicon carbide, 10-18% of micropowder-grade ceramic corundum, 8-12% of modified resin, 5-15% of glass beads, 1-4% of cryolite powder and 1-4% of zinc oxide, and the cryolite powder and the zinc oxide serve as filling agents. Micropowder-grade ceramic corundum abrasive materials can conduct self-sharpening at the nanoscale size during the grinding process, and micro grinding edges are exposed continuously, so that the cutting depth can be increased, and the grinding efficiency can be improved. Poor grinding faces caused by smoothed and blunted abrasive particles can be avoided through the micro grinding edges exposed continuously. During production of the grinding wheel, water pressure pads are adopted in the diameter direction and the thickness direction of the grinding wheel, and the balance performance and structure uniformity of the grinding wheel are improved by 50% more than the specified value of the national standard.

The invention discloses a quenching lift for a bearing ring. The quenching lift comprises a motor, a frame, a workbench, a crank connecting rod mechanism and a power transmission mechanism. A transmission shaft of the power transmission mechanism is supported on the frame through bearings on two ends, and a first spindle and a second spindle are respectively arranged on two sides of the transmission shaft. A motor belt pulley is connected to a big belt pulley through a belt, a drive chain wheel on the big belt pulley shaft is connected to a driven chain wheel through a chain, the driven chain wheel drives an intermediate chain wheel, the intermediate chain wheel is connected to a large driven chain wheel on the transmission shaft through the chain, and two same drive chain wheels on the transmission shaft are respectively connected to a first spindle chain wheel and a second spindle chain wheel through the chain. Cranks of the crank connecting mechanism are respectively arranged on two ends of the first spindle and the second spindle, a cylinder sleeve and the frame are fixed through a support plate, and a piston in the cylinder sleeve is connected to the workbench through a vertical shaft of the workbench. According to the quenching lift for the bearing ring, the quenching hardness uniformity is improved by 2-3 HRC, the problems of uneven hardness and soft spots during quenching of the bearing ring are completely solved, the quenching efficiency is high, and the product quality is stable.

The invention discloses a double-ring differential centrifugal pressure vacuum casting system with enhanced ceramic density. The double-ring differential centrifugal pressure vacuum casting system with the enhanced ceramic density structurally comprises a shaft-driven motor, a power distribution block, a gear top cover seat, a rotating shaft column rod, a side frame support arm, a sliding frame pouring tank and lug fixing columns. According to the double-ring differential centrifugal pressure vacuum casting system, the cooperation of the rotating shaft column rod and the sliding frame pouringtank can be realized, the fine machining effect of an upper arc top sliding ring and a lower arc top sliding ring is achieved, and the effect of disturbance cooling and sweeping after pouring is formed; thickening stirring is carried out on the consistency of the clay through a display panel slide sheet and a corrugated liner plate, the slow pulling traction overall clay forms a transverse extension laying, and the clay molecular density at the early stage of the ceramic casting is ensured to be uniform, so that the compactness and smoothness of post-forming of the ceramic are optimized; and the polishing effect of the sliding rings as well as the vibration isolating operation enable the hardness uniformity after ceramic casting cooling is extremely high, the falling-resistant strength isimproved, the sliding-drawing leveling effect is formed for the concave-convex groove surface inside, the quality of the ceramic finished product is high, the processing and crushing probability is low, the cost is saved, and the forming efficiency is improved.

The invention discloses a differential-temperature heat treating method for a roller, and relates to the technical field of heat treating. The differential-temperature heat treating method includes the steps of a technological preparation stage, a preheating stage, a differential-temperature preheating stage, a high-speed temperature rising stage and a high-temperature heat preservation stage. According to the differential-temperature heat treating method, the preheating temperature is low and is 480 DEG C to 500 DEG C, the constant temperature before high-speed temperature rising is 800 DEG C to 850 DEG C, a stage-type temperature rising mode is adopted for the high-speed temperature rising stage, three temperature rising nodes exist, heat preservation is carried out for two minutes every time one temperature node is achieved, high-temperature heat preservation is divided two stages, and the heat preservation time and the temperature of the two stages are different. The roller prepared with the heat treating method has high hardness evenness and the good core microstructure, energy consumption of heat treatment can be reduced, and the production cost of an enterprise can be reduced.