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

The invention provides a method for manufacturing a 105ksi steel grade sulfide stress corrosion resistant drill rod material. The method comprises the following steps of: smelting waste steel, sponge iron and (or) blast furnace molten iron serving as raw materials through an arc furnace, forming slag and removing phosphorus, performing ladle external refining, deoxidation, desulfuration and inclusion removal, adjusting and controlling chemical components, performing vacuum degassing, performing modification treatment on a calcium silk feeding inclusion, and performing continuous casting to form round billets; feeding the round billets into an annular furnace, and performing high-temperature heating, perforation and precise controlled continuous casting to prepare seamless steel tubes; andperforming tube end upsetting, tempering, thermal treatment and thermal straightening on the seamless steel tubes, cooling to room temperature, and performing flaw detection, mechanical property testand sulfide stress cracking (SSC) test. The manufacturing method has the advantages of low alloy content, low production cost, simple process and easiness in operation; based on the metallurgical clean steel, trace alloy components are added, so that the full hardening performance of the steel is improved; and the thermally treated tempered martensite tissues in which fine carbide granules are uniformly distributed have good SSC resistance.

The invention discloses a tempering heat treatment method of Mn-series high-strength finish rolling thread reinforcing steel bars. The method comprises a temperature rising process, a heat preservation process and a cooling process. According to the heat preservation process, the heat preservation temperature ranges from 200 DEG C to 600 DEG C, and the heat preservation time ranges from three hours to six hours. According to the method, a heat treatment heating furnace is utilized for performing heating, a martensitic structure obtained after rolled air cooling is decomposed, supersaturated carbon in martensite is precipitated, a reversed crystal lattice is basically restored to be normal, and therefore structural stress is eliminated, and a steel material structure is converted into bainite and a corresponding tempering structure; along with disappearance of the martensite, the strength of steel is reduced, the heat preservation time is increased, the steel hydrogen content is reduced, the hydrogen embrittlement sensitivity of the steel is greatly reduced, obdurability of the high-strength finish rolling thread reinforcing steel bars is ensured, and the structural stress and the hydrogen embrittlement sensitivity are reduced. According to the method, the obdurability of the high-strength finish rolling thread reinforcing steel bars is ensured, the structural stress and the hydrogen embrittlement sensitivity are reduced, meanwhile, the production technology is simplified, the equipment requirement is reduced, and the method has the advantages of being simple in process and low in production cost.

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 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 a thermoforming production line and production method of variable-strength parts. The production line includes a destacking device, a feeding device, a first heating furnace, a second heating furnace, a discharging device, a press and a feeding device arranged in sequence. device, the discharge side of the first heating furnace is provided with a blowing cooling device, the press is provided with a variable strength coating mold, and the variable strength coating mold includes a soft area with a thermal barrier coating on the surface And the hard area with built-in cooling water circuit. The invention can partially and briefly cool the billet just out of the furnace, and control the forming temperature of the billet within an ideal range. For the variable strength thermoformed part, the position of the soft zone can be any position of the part, and at the same time, the transition interval between the soft zone and the hard zone is narrow, and the elongation of the soft zone is high, and the production efficiency is fast.

The invention provides a vacuum step gas quenching method of a D6AC ultra-high strength steel thin-walled shell. The vacuum step gas quenching method of the D6AC ultra-high strength steel thin-walledshell comprises the steps of heating D6AC ultra-high strength steel to 900 degrees centigrade under a vacuum degree of 6.7x10<-2> Pa in two steps; cooling the D6AC ultra-high strength steel to 50 degrees centigrade under the atmosphere of 2 bar high-purity nitrogen in four steps; and discharging the D6AC ultra-high strength steel out of a furnace to be cooled by air. According to the vacuum step gas quenching method of the D6AC ultra-high strength steel thin-walled shell, by using a vacuum step gas quenching method, decarburization in heat treatment can be prevented, the mechanical performancecan be improved, deformation can be reduced, and meanwhile, the high-purity nitrogen is adopted to replace quenching oil, and the high-purity nitrogen is extracted from the air, and therefore, the production of the high-purity nitrogen is convenient, and the high-purity nitrogen is clean and pollution-free.

The invention relates to a method for overcoming the cracking defects of the 4140 steel oil pipe hanger body. Firstly, the blank is heated in sections, then the basic process is prepared, and then the mold is forged, and then cooled with lime sand, and finally the formed workpiece is quenched and tempered. heat treatment. This application heats the billet slowly to make the internal structure change slowly, which plays the role of grain refinement and uniform structure. The actual grain size can reach 7 to 10 grades, avoiding the Widmanstatten caused by overheating and overheating. organizations and other harmful organizations. The die forging method is used to avoid excessive surface stress caused by free forging hammer forging. It is forged from multiple directions successively to increase the fluidity of the billet and avoid the generation of knife patterns and the formation of main cracks. In the final quenching, slow down the quenching cooling rate and reduce the cooling rate in the martensite transformation zone, thereby avoiding transgranular expansion, reducing the structural stress of martensite transformation, and avoiding macroscopic cracks.

The invention discloses a micro-alloyed medium-thick plate with high strength and toughness and good metallurgical quality at the core and a preparation method thereof, belonging to the field of hot-rolled steel plate manufacturing. The microalloyed plate with high strength and toughness and good metallurgical quality in the core includes: 0.07‑0.17% of C, 0.05‑0.3% of Si, 0.8‑1.9% of Mn, 0.0005‑0.018% of P, and 0.0005‑05% of S 0.010%, Cr is 0.05‑0.25%, Nb is 0.005‑0.03%, Mo is 0.05‑0.3%, V is 0.09‑0.25%, N is 0.012‑0.025%, and the balance is Fe and unavoidable impurity elements; The metallographic structure of the core is acicular ferrite, granular bainite and pearlite. Its preparation method goes through molten iron pretreatment, smelting, LF refining, continuous casting, rough rolling, finish rolling, cooling, and through optimization of chemical composition, smelting, rolling, and cooling processes, the allowable hydrogen content in molten steel is increased to 4.5 ppm, no vacuum degassing process is required, which makes the steel plate have strong toughness and good core metallurgical quality.

The invention discloses an inorganic polymer water-soluble quenching medium which has reasonable cooling characteristic distribution and stable performance, is safe and environmentally friendly and has lower cost, and a preparation method thereof. The quenching medium is an aqueous solution formed by mixing polyaluminium chloride, sodium hydroxide, zinc chloride, potassium chloride and water, wherein the concentration of the aqueous solution is 8-35 Baume and the aqueous solution comprises the following raw materials by weight percent: 59-62% of the polyaluminium chloride, 19-21% of the 10% sodium hydroxide, 14-16% of zinc chloride, 11-13% of the potassium chloride and the balance water. The preparation method comprises the following steps in sequence: adding the polyaluminium chloride and water in a container, and stirring until the polyaluminium chloride is fully dissolved; adding the 10% sodium hydroxide solution in the container, and stirring evenly; dissolving the zinc chloride in water, then adding the zinc chloride solution in the container, and stirring evenly; dissolving the potassium chloride in water, then adding the potassium chloride solution in the container, and stirring evenly; and adding water to ensure that the concentration of the solution in the container is 8-35 Baume.

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.

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 provides a carburizing and quenching method for large heavy-duty gears, which includes a segmented heating and uniform temperature step, a carbon potential step-by-step lowering carburizing step, a segmented cooling and uniform temperature step, a graded quenching step, and a low-temperature tempering step . The carburizing and quenching heat treatment method for large heavy-duty gears provided by the present invention can not only shorten the heat treatment cycle, improve production efficiency, save energy consumption, but also effectively control the heat treatment deformation of the gear, optimize the metallographic structure of the gear surface, and improve the wear resistance of the gear. Comprehensive mechanical properties.

A non-Co multi-element high-speed tool steel contains proportionally C, Si, Mn, S, P, Cr, V, Mo, W, Ni, Nb, Ti, Mg, RE and Fe. Its preparing process includes such steps as smelting by MF furnace, modifying with Y-based RE alloy, centrifugal casting, and heat treating.