32results about How to "Reduce tissue stress" patented technology

The present invention relates to the preparation of cermet material, and the sintered alloy has submicron crystal grain structure, and high hardness, toughness and strength. The cermet is prepared through mixing IVB, VB, VIB, Ti, one or more metal carbide, nitride or complex solid solution carbide-nitride ceramic powder and iron family element Ni, Co, etc.; high-energy ball milling, drying, pressing to form, vacuum sintering, hot isostatic pressing and other steps. The cermet has hard crystal phase reaches submicron granularity of 0.6-1.0 micron. Under scanning electronic microscope, four kinds of metal structure may be observed including black core phase, white core phase, gray ring phase and white adhesion phase. Compared with available cermet, the present invention has obviously improved hardness and toughness, and may be used in cutter and other wear resistant parts.

The invention provides a spheroidizing annealing technology of H13 hot work die steel and belongs to the field of die steel heat treatment technologies. The spheroidizing annealing technology of the H13 hot work die steel comprises the steps that (1) a forged H13 steel blank is cooled to the temperature of 400-500 DEG C, the cooled H13 steel blank is fed into a furnace, the temperature is raised to 720-750 DEG C at the temperature raising speed of 25-80 DEG C per hour for preheating, the temperature is kept for 1-2 hours, the temperature is then raised to 980-1050 DEG C at the temperature raising speed of 25-80 DEG C per hour, after all the furnace charge reaches the temperature, the temperature is kept for 3-5 hours, then the temperature of the forged H13 steel blank is lowered to be not higher than 550 DEG C through furnace cooling, and air cooling and discharging are conducted; hot charging is conducted, the temperature is raised to 900-950 DEG C at the temperature raising speed of 25-80 DEG C per hour, after all the furnace charge reaches the temperature, the temperature is kept for 0.5-1 hour, air cooling and discharging are conducted, and then the pre-treatment process is completed; and charging is conducted at the temperature 300-400 DEG C, the temperature is raised to 880+/-10 DEG C at the temperature raising speed of 25-80 DEG C per hour, the temperature is kept for 4-6 hours, the temperature is lowered to 760+/-10 DEG C at the cooling speed of 15-20 DEG C per hour, after the temperature is kept for 8-12 hours, the H13 hot work die steel is cooled to be lower than or equal to 500 DEG C at the cooling speed of 15-20 DEG C per hour, and then air cooling and discharging are conducted. The spheroidizing annealing technology of the H13 hot work die steel has the advantages that carbides are evenly distributed in the structure, the structure is refined, the defects of network carbides and the like in an original structure are eliminated, and the annealing hardness is lowered.

The invention discloses an anti-cracking machining method of a small axial surface carburizing and hardening stepped shaft with an end face provided with a groove. The groove is arranged in an end face of a shaft section B of the stepped shaft, a shaft section A and a side face, close to the shaft section A, of the shaft section B have carburizing and hardening requirements, other parts have no hardness requirements, 20Cr steel serves as blanks of the stepped shaft, the procedures of blanking, rough machining, carburizing treatment, semi finish machining, hardening, fine machining, cutting and groove milling are sequentially carried out on the blanks, and then the stepped shaft with different shaft sections having different mechanical properties are machined. The anti-cracking machining method is simple in structure and convenient to achieve; a protective step is arranged before carburizing, the protective step before the hardening is machined to be a fillet, and cracking caused by oversize stress when the carburizing and hardening are carried out on the root portion of the step can be effectively avoided; a shaft section B carburized layer is milled off before the hardening, the hardness of the shaft section B after the hardening is reduced, and machining efficiency of following steps is improved.

The invention relates to a method and device for progressive austempering heat treatment of bainite and martensite complex-phase steel/iron, and belongs to the technical field of metallic material heat treatment processes. The method comprises the following steps: performing water cooling on an austenitized workpiece for a certain period of time, taking out the workpiece for air cooling, and enabling the inner and outer temperatures of the workpiece to be close to each other by using waste heat temperature returning, thereby finishing a heat treatment cycle; putting the inner and outer parts of the workpiece into a lower bainite transformation temperature zone after finishing multiple heat treatment cycles; then performing isothermal transformation by using waste heat temperature returning or heat preservation by an insulation can; and finally performing air cooling to finish martensite transformation. By adopting the method, the defect that a workpiece with a relatively large wall thickness is easy to crack and generate early cracks during quenching can be overcome, and the obtained product is uniform in structure, good in comprehensive mechanical property, reliable in operation and low in cost and is green and environmentally-friendly.

The invention relates to a quench cooling process for H13 steel. The process sequentially comprises a grading heating step, a gas cooling step, a water cooling step and an air cooling step. During quench cooling in the invention, gas cooling, water cooling and air cooling occur in order. Water cooling speeds up the cooling rate of quenching, so that austenite is rapidly supercooled to a martensite region, thus ensuring a martensitic structure obtained during quenching. The air cooling after water cooling greatly slows down the cooling rate, therefore, the structural stress generated when the austenite structure transforms into the martensitic structure is reduced, thus guaranteeing that a workpiece does not crack and a deeper hardening layer can be obtained. The process provided in the invention is suitable for quench cooling of H13 steel.

The invention discloses 1000MPa-grade high-toughness and high-magnetism hot-rolled magnetic yoke steel and a production method thereof. The 1000MPa-grade high-toughness and high-magnetism hot-rolled magnetic yoke steel is prepared from the following components in percentage by weight: 0.20 to 0.50 percent of C, 0.2 to 1.0 percent of Si, 0.5 to 1.5 percent of Mn, less than or equal to 0.015 percentof P, less than or equal to 0.005 percent of S, less than or equal to 0.06 percent of Ti, less than or equal to 0.05 percent of Nb, 0.20 to 1.0 percent of Mo, 0.20 to 1.20 percent of Cr, 0.20 to 0.60percent of Ni, 0.03 to 0.15 percent of V, 0.0005 to 0.003 percent of B, 0.015 to 0.10 percent of Al, less than or equal to 0.010 percent of N, less than or equal to 0.0080 percent of O, and the balance of Fe and other unavoidable impurities; and meanwhile Cr+Mo+Ni is larger than or equal to 0.80 percent; Nb+V+Ti is larger than or equal to 0.06 percent; carbon equivalent CEV is larger than or equal to 0.50 percent. The yield strength of the hot-rolled magnetic yoke steel is larger than or equal to 1000MPa, the tensile strength is larger than or equal to 1050MPa; the impact power KV<2> is larger than or equal to 40J at the temperature of 20 DEG C below zero; the magnetic induction performance B<50> is larger than or equal to 1.58T; B<100> is larger than or equal to 1.73T; B<200> is larger than or equal to 1.90T; and B<300> is larger than or equal to 1.93T. The 1000MPa-grade high-toughness and high-magnetism hot-rolled magnetic yoke steel meets relevant requirements of the hydropower industry on rotor magnetic yoke steel.

A heat treatment process for high-hardenability Martensitic stainless steel for moving blades includes the following steps: (1) a forged workpiece is cooled to 50 DEG C to 90 DEG C by the air and loaded into a furnace, and the temperature is increased to 1120 DEG C to 1160 DEG C after 1 to 2 hours of constant temperature; (2) after the temperature is preserved for 8 to 10 hours, three times of water quenching are carried out; (3) the workpiece is blown by a fan, rotated and cooled to 250 DEG C to 280 DEG C, and cooling under cover is started; (4) the workpiece is cooled under cover to 100 DEGC, loaded into a furnace and tempered to remove stress, and the tempering temperature is between 650 DEG C and 680 DEG C; (6) the workpiece is taken out of the furnace, recooled to 200 DEG C by waterand then cooled to the room temperature by the air. The heat treatment process effectively meets the technical requirements of moving blades, also effectively controls the content of residual austenite, and guarantees the dimension stability of the moving blade workpiece, and more importantly, the heat treatment process solves the problems of deformation and cracks in heat treatment.

The invention discloses a microalloyed medium-thickness plate with high strength and toughness and good core metallurgical quality and a preparation method thereof, and belongs to the field of hot-rolled steel plate manufacturing. The microalloyed medium-thickness plate with high strength and toughness and good core metallurgical quality comprises 0.07-0.17% of C, 0.05-0.3% of Si, 0.8-1.9% of Mn, 0.0005-0.018% of P, 0.0005-0.010% of S, 0.05-0.25% of Cr, 0.005-0.03% of Nb, 0.05-0.3% of Mo, 0.09-0.25% of V, 0.012-0.025% of N and the balance Fe and inevitable impurity elements. The metallographic structure of the core of the microalloyed medium-thickness plate is acicular ferrite, granular bainite and pearlite. The preparation method of the microalloyed medium-thickness plate comprises the steps of molten iron pretreatment, smelting, LF refining, continuous casting, rough rolling, finish rolling and cooling. By optimizing the chemical components, smelting, rolling and cooling processes, the allowable hydrogen content in molten steel is increased to 4.5ppm, the vacuum degassing process is not needed, and the steel plate has high strength and toughness and good core metallurgical quality.

The invention discloses a heat forming production line and production method of a variable strength part. The production line comprises an unstacking device, a feeding device, a first heating furnace,a second heating furnace, a material outgoing device, a pressing machine and a discharging device which are sequentially arranged; a gas blowing cooling device is arranged on the discharging side ofthe first heating furnace; and a variable strength coating mold is arranged in the pressing machine, and comprises a soft area provided with a thermal barrier coating on the surface and a hard area internally provided with a cooling water way. Due to the heat forming production line and production method of the variable strength part, blank which is just discharged out of a furnace can be subjected to local transitory cooling, and the forming temperature of the blank is controlled within an ideal range. According to the prepared variable strength heat formed part, the soft area position can beany position of the part, meanwhile, a transition interval of the soft area and the hard area is narrow, the soft area is high in extending rate, and the production efficiency is high.

The invention relates to a method for overcoming the explosion defect of a 4140 steel tubing hanger body. Firstly, a blank is heated section by section, then basic procedures are prepared, then die forging is carried out, then lime sand cooling is used for cooling, and finally a formed workpiece is subjected to quenched-tempered heat treatment. As the blank is slowly heated, the internal structureof the blank slowly changes, the effects of refining grain and homogenizing the structure are achieved, the actual grain size can reach a 7-10 level, and harmful structures such as a Widmannstatten structure generated by overburning and overheating are avoided. Due to the manner of die forging, too large surface stress triggered by hammer forging of free forging is avoided, sequential forging iscarried out in multiple directions, the fluidity of the blank is improved, and knife patterns and main cracks are avoided. During final quenching, the quenching cooling speed is reduced, the cooling speed of a martensite transformation region is reduced, thus, transgranular extension is avoided, structural stress of martensite transformation is reduced, and macroscopic cracks are avoided.

The invention belongs to the technical field of metal material heat treatment, and particularly relates to a carburizing and quenching process of a thin-wall gear. The process comprises the following steps: low-temperature tempering and air cooling treatment is performed on the thin-wall gear after gear shaping; the thin-wall gear is subjected to pre-oxidation treatment, the temperature ranges from 400 DEG C to 500 DEG C, and the time ranges from 1 h to 2 h; carburizing treatment is conducted on the thin-wall gear; the thin-wall gear is heated to 900-930 DEG C in stages; strong carburizing treatment is conducted on the heated thin-wall gear for 3-5 h under the conditions that the temperature ranges from 900 DEG C to 930 DEG C and the carbon potential ranges from 1.0% to 1.2%; diffusion treatment is performed for 1 to 2 hours at the temperature of 900 to 930 DEG C and the carbon potential of 0.7 to 0.9 percent; the temperature is reduced to 800 DEG C to 850 DEG C under the condition that the carbon potential is 0.7% to 0.9%; temperature equalization treatment is performed under the conditions that the carbon potential is 0.7-0.9% and the temperature is 800-850 DEG C; the thin-wall gear is subjected to staged oil quenching cooling treatment; and after cooling of the thin-wall gear is finished, oil draining, cleaning, low-temperature tempering and air cooling are sequentially conducted, and carburizing and quenching are completed. The carburizing and quenching deformation of the thin-wall gear can be controlled, and it can be ensured that the heat treatment performance and the structure are not out of tolerance.

The invention discloses an ammunition belt heat treatment process, which comprises: heating a work-piece to austenitize and homogenize, cooling to a temperature of 240-260 DEG C in a nitrate tank, carrying out isothermal maintaining, and carrying out water cooling. According to the present invention, with the ammunition belt heat treatment process, the requirements that the mechanical performance index of the ammunition belt are substantially improved and the qualification rate is increased to 100% are fundamentally met.

The invention provides a treatment method for improving the tensile property qualification rate of a steel plate, and belongs to the technical field of steel and iron. The treatment method comprises the following steps that for a first stage, the steel plate is placed on a cooling bed and cooled to 300-550 DEG C; for a second stage, natural aging is carried out on the steel plate for 24 h or abovein a lower line stacking slow cooling manner, the steel plate is slit to obtain a plurality of sub-steel plates when the surface temperature of the steel plate is less than or equal to 150 DEG C, andsampling and initial inspection sample machining are carried out; and for a third stage, natural aging is carried out on an initial inspection sample and the plurality of sub-steel plates corresponding to the initial inspection sample for 24-72 h, and the tensile property of the initial inspection sample subjected to natural aging is detected. Compared with the mode of directly detecting the tensile property of the initial detection sample in the second stage, the method has the advantage that the qualification rate of the tensile property of the steel plate can be improved through the treatment in the third stage.

The invention relates to the technical field of slotting cutter manufacturing, and discloses a manufacturing process of an ultra-thin slotting blade. According to the manufacturing procedure, the process sequentially includes the steps of forging and annealing a blank, lathing and grinding the two end faces, performing finish turning on an outer circle, grinding the flat face, cutting an inner hole through a slow-feeding wire, grinding the inner hole, cutting a key groove through the wire, cutting a cylinder into a blade through the slow-feeding wire, accurately grinding a blade supporting face, accurately grinding a blade front edge face, grinding a tooth profile and a relief angle, performing mirror grinding on a front blade face, passivating a cutting edge and conducting coating. In theblank forging and annealing step, multiple blades are combined and forged into the cylinder blank. The demagnetizing step is executed between the step of lathing and grinding the two end faces and the step of performing finish turning on the outer circle. The steps of heat treatment, destressing, surface sand blasting and cold treatment are sequentially executed between the step of performing finish turning on the outer circle and the step of grinding the flat face. By means of the manufacturing process, the manufacturing quality of the ultra-thin slotting blade is improved.