106results about "Heat treatment baths" patented technology

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 1960MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After high-carbon components containing trace B are designed, rolled and spun into a wire rod, online molten salt rapid quenching treatment is carried out, and the wire rod is firstly subjected to front-section molten salt treatment, so that the wire rod is cooled at the cooling speed of greater than or equal to 36 DEG C / s and enters a bainite and pearlite mixed phase region from an austenite state; the method comprises the following steps: quenching a steel wire rod to form a structure mainly comprising quenched bainite and a sorbite structure, carrying out rear-section molten salt treatment on the steel wire rod, increasing the molten salt temperature, promoting isothermal tempering of the quenched bainite and the sorbite structure, and carrying out roller way slow cooling to prepare the hot-rolled steel wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered sorbite, tempered bainite and ferrite, the composition system can be simplified, the strength and plasticity matching and rapid production of the wire rod are considered, the tensile strength is 1330-1380 MPa, the percentage reduction of area is 35%-40%, and the wire breaking risk in the wire drawing and twisting process of the stranded wire steel can be reduced.

The invention relates to a hot-rolled wire rod for a 2260MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod, after the high-carbon component design of C-Si-Mn-Cr-Mo-Nb-Al is adopted for rolling and spinning to form the wire rod, online molten salt isothermal toughening treatment is carried out, so that the wire rod is firstly subjected to front-section molten salt treatment and is rapidly cooled, and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure; and then carrying out rear-section molten salt treatment, reducing the circulation volume of molten salt, promoting the unconverted retained austenite to be continuously converted into sorbite, carrying out isothermal tempering, promoting fusing of a part of sorbite lamellar layers, and finally carrying out slow cooling through a roller way, so as to prepare the hot-rolled wire rod of which the microscopic structure comprises a mixed structure consisting of tempered sorbite, ferrite and fused sorbite, the tensile strength can reach 1534-1584 MPa, the percentage reduction of area can reach 33%-38%, and the alloy can be used in the application fields of manufacturing 2260 MPa grade stranded wires and the like without additional heat treatment procedures.

The invention relates to a hot-rolled wire rod for a 2200MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod, after Nb-Al high-carbon component is rolled and spun into a wire rod, the wire rod is subjected to online molten salt strong isothermal treatment, so that the wire rod is firstly subjected to front-section molten salt treatment and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure, and then is subjected to rear-section molten salt treatment to form the hot-rolled wire rod for the 2200MPa-grade stranded wire. The molten salt temperature is increased, the molten salt circulation amount is reduced, unconverted retained austenite is promoted to be continuously converted into sorbite, isothermal tempering is carried out, part of sorbite lamellas are promoted to be fused, and finally slow cooling is carried out through a roller way, so that the hot-rolled wire rod with the microscopic structure comprising a mixed structure composed of tempered sorbite, ferrite and fused sorbite is prepared. According to the method, abnormal structures can be inhibited, the strength of a hot-rolled wire rod can be improved, plasticity and production efficiency are both considered, the tensile strength is 1490-1540 MPa, the percentage reduction of area is 34%-39%, downstream users can avoid off-line heat treatment, and stable production of stranded wires is promoted.

The utility model relates to the technical field of traction motor bearing manufacturing, in particular to a deep groove ball bearing which comprises an outer ring, an inner ring, a plurality of rolling bodies and a retainer, the outer surface of the inner ring and the inner surface of the outer ring are respectively provided with a roller path for the rolling body to roll; the rolling body is located between the outer ring and the inner ring, and the retainer is located between the outer ring and the inner ring; the guide mode of the deep groove ball bearing is rolling body guide; the groove curvature coefficient of the outer ring is 0.520 Dw, and the groove curvature coefficient of the inner ring is 0.510 Dw. The curvature coefficient of the inner and outer ring channels is reduced by 0.005 Dw compared with a conventional bearing, and the contact area of the raceway and a rolling body is increased under the condition, so that the load borne by the unit area is reduced, the stress concentration and fatigue crack possibility is reduced, the operation temperature rise and vibration of the bearing under the high-speed working condition are reduced, and the fatigue life of the bearing is prolonged.

The invention relates to a 1150MPa-grade high-strength carbon tool steel wire rod and a manufacturing method thereof.The 1150MPa-grade high-strength carbon tool steel wire rod comprises, by mass, 0.57%-0.62% of C, 0.38%-0.47% of Si, 0.53%-0.63% of Mn, smaller than or equal to 0.015% of P, smaller than or equal to 0.015% of S and the balance Fe and inevitable impurities, after the wire rod is rolled and spun, online molten salt isothermal toughening treatment is conducted on the wire rod, the wire rod is controlled to enter a sorbite phase region from a high-temperature austenite state, and the steel wire rod is subjected to high-temperature annealing treatment; the method comprises the following steps of: preparing a steel wire rod of which the microscopic structure comprises tempered sorbite, ferrite and fused sorbite, forming a structure mainly comprising fine lamellar spacing sorbite, carrying out isothermal tempering, and finally slowly cooling through a roller way, so that the steel wire rod of which the microscopic structure comprises tempered sorbite, ferrite and fused sorbite can reach the tensile strength of 1050-1100MPa and the percentage reduction of area of 45-50%, and can be applied to the application fields of manufacturing carbon tool steel and the like. And therefore, a tool part can be directly processed after cold forming.

The invention relates to a 1100MPa-grade high-strength carbon tool steel wire rod and a manufacturing method thereof, a carbon component design is adopted, the rolled and spun wire rod is subjected to online molten salt isothermal toughening treatment, and the wire rod is controlled to enter a sorbite phase region from a high-temperature austenite state at a cooling speed of more than or equal to 32 DEG C / s to form a structure mainly comprising fine lamellar spacing sorbite; the steel wire rod is controlled to be subjected to isothermal tempering, sorbite lamellar fusing promotion and toughening destressing treatment in an isothermal interval, and finally the steel wire rod with the microscopic structure comprising tempered sorbite, ferrite and fused sorbite is manufactured through roller way slow cooling, so that the material cost can be reduced, the overall strength and plasticity of the steel wire rod can be improved, the tensile strength is 1020-1070 MPa, the percentage reduction of area is 46%-51%, and the steel wire rod can be manufactured into the steel wire rod with the microstructure comprising tempered sorbite, ferrite and fused sorbite. Therefore, the tool part can be directly machined after cold machining, additional heat treatment after cold machining is omitted, the production cost and energy consumption of downstream users are reduced, and the production efficiency and the yield are improved.

The invention provides cooling equipment and process for isothermal quenching nodular cast iron production, and relates to the technical field of nodular cast iron material production, the cooling equipment comprises a cooling mechanism, a lifting mechanism, a supporting mechanism, a multifunctional mechanism A and a multifunctional mechanism B; the lifting mechanism is mounted on the cooling mechanism; the supporting mechanism is mounted on the lifting mechanism; the number of the multifunctional mechanisms A is two, and the two multifunctional mechanisms A are installed on the cooling mechanism and the lifting mechanism. The number of the multifunctional mechanisms B is two, and the two multifunctional mechanisms B are installed on the front side and the rear side of the cooling mechanism. The two rectangular protection plates automatically turn inwards under the action of the four L-shaped driving frames and the four driving gears, the automatic protection effect is achieved, steam or quenching liquid is prevented from being splashed out, and potential safety hazards are reduced; the problems that a large amount of steam is emitted during quenching and a small amount of quenching liquid is splashed due to the lack of an automatic protection structure generally, and potential safety hazards exist are solved.

The invention discloses an on-line spheroidizing annealing production method for high-strength B-containing cold forging steel, the method sequentially comprises the steps of converter smelting, LF + RH refining, continuous casting, casting blank heating, rolling, spinning, on-line isothermal treatment, hot coil collection, heat preservation gallery heating and slow cooling, the casting blank heating temperature is 1000-1050 DEG C, the rolling and finishing mill entering temperature and the reducing and sizing temperature are 800-850 DEG C, and the rolling and finishing mill entering temperature is 800-850 DEG C; the spinning temperature ranges from 800 DEG C to 850 DEG C, the temperature of online isothermal treatment ranges from 430 DEG C to 450 DEG C, and the heating temperature of the heat preservation gallery enables the wire rod to be heated to 680 DEG C to 700 DEG C; the spheroidizing grade of the wire rod reaches grade 6, light drawing and cold heading machining can be directly carried out, direct fastener forming is achieved, one-time large drawing and off-line annealing are omitted, the overall machining process is shortened by more than 40%, annealing energy consumption is reduced by more than 60%, and green carbon reduction is achieved.

In order to subject a metal member to cooling under isothermal heat treatment, a salt-bath heat treatment apparatus 10 comprises: a salt bath tank 1 which accommodates a nitrate salt bath including a molten nitrate salt; a water addition device 2 to add water to the nitrate salt bath in the salt bath tank 1; a humidity detection device 5 comprising a humidity sensor 53a to output a signal corresponding to humidity caused by water vapor generated from the nitrate salt bath with water added by the water addition device 2; and a control device 100 configured to control the water addition device 2 to adjust an addition amount of water to the nitrate salt bath, based on the signal output from the humidity sensor 53a of the humidity detection device 5.

Disclosed are a wire rod and a steel wire for a spring, a spring with improved strength and fatigue limit, and a method for manufacturing the same. The disclosed wire rod for a spring with improved strength and fatigue limit according to an embodiment includes, in percent by weight (wt%): 0.6 to 0.7% of C, 2.0 to 2.5% of Si, 0.2 to 0.7% of Mn, 0.9 to 1.5% of Cr, 0.015% or less of P, 0.01% or less of S, 0.01% or less of Al, 0.01% or less of N, 0.25% or less of Mo, 0.25% or less of W, 0.05% to 0.2% of V, 0.05% or less of Nb, and the balance of Fe and unavoidable impurities, wherein Mn+Cr≤1.8% and 0.05 at%≤Mo+W≤0.15 at% may be satisfied.

The application provides a fixing device for a salt bath experiment, which comprises a fixing frame, a first fixing assembly and a second fixing assembly, wherein the fixing frame comprises a lower frame body and a top plate, the lower frame body is provided with a containing portion and a first opening, the first opening is located at the top of the lower frame body, the first opening is communicated with the containing portion, the top plate is detachably arranged on the lower frame body and located at the first opening; the first fixing assembly is arranged on the lower frame body and extends along the height direction of the lower frame body, the first fixing assembly can move in the length direction relative to the lower frame body, and the first fixing assembly can fix a plate; the second fixing assembly is arranged on the top plate and extends along the length direction of the lower frame body, the second fixing assembly can move in the height direction relative to the lower frame body, and the second fixing assembly can fix the plate. Through the technical scheme, the problem that the plate is prone to deformation in the salt bath experiment in the prior art can be solved.

The invention discloses a heat treatment process of an M62 material for an X-ray tube bearing. The heat treatment process comprises the following steps: S1, preparing the M62 material; s2, the M62 material is subjected to high-temperature annealing process machining, and the M62 material subjected to high-temperature annealing process machining is subjected to turning treatment to obtain a bearing turning part; s3, the bearing turning part is subjected to third-time preheating machining, and the bearing turning part subjected to third-time preheating machining is subjected to quenching heat preservation treatment; s4, on the basis of the step S3, isothermal quenching machining is conducted on the bearing turning part subjected to quenching and heat preservation treatment; and S5, based on the step S4, low-temperature tempering machining is conducted on the bearing turning part subjected to isothermal quenching machining, and high-temperature tempering machining is conducted on the bearing turning part subjected to low-temperature tempering machining twice. The method solves the problems of low cutting efficiency caused by high annealing hardness after heat treatment of the traditional M62 material, high material performance dispersity and shortened service life caused by non-uniform heating of the internal structure of the alloy, and overhigh hardness and insufficient toughness after heat treatment.

The application discloses a preparation process of a new material cab turnover support for a heavy truck, and the cab turnover support is made of a new alloy material by adopting a temperature control rolling and air quenching and partitioning heat treatment process.The Ti element is added in the alloy composition, and compared with other alloy elements, the carbide of the Ti element has super-high hardness; the process of temperature control rolling is adopted, a large number of dislocations are introduced into austenite, and austenite grains are refined; the heat treatment process of air cooling quenching and partitioning is adopted, a kind of wear-resistant steel with a complex structure of martensite + austenite is obtained, the strength of the steel plate is improved, and good toughness and plasticity are simultaneously achieved.Compared with the cab turnover support made of the DC04 steel by adopting the cold continuous rolling and annealing heat treatment in the prior art, the cab turnover support has high strength and wear resistance, the mechanical property is improved by nearly 4 times, and the light weight requirement of the cab turnover support is met.

Described herein is a method for treating a metal golf club head through a series of post-assembly steps to provide a hardened black coating. The method described herein includes a quench-polish-quench (QPQ) process that results in a surface coating with better hardness, uniformity, and porosity characteristics, thereby reducing visible surface deformation and loss of durability.

The utility model relates to the technical field of austenite-bainite rolling ball production, and provides an automatic isothermal salt bath heat treatment device for austenite-bainite rolling ball production, which comprises a tank body, a filter plate, a stirring paddle, two lifting mechanisms and a stirring mechanism, the filter plate is arranged in the tank body in a sliding manner, the stirring paddle is arranged in the tank body, the two lifting mechanisms are arranged on the tank body, and the stirring mechanism is arranged on the tank body. The lifting mechanism is arranged in the tank body and is used for driving the filter plate to lift and move, the stirring mechanism is arranged in the tank body and is used for stirring the austempered rolled balls and a salt bath medium, and the lifting mechanism comprises a stretching rope, a winding assembly and a supporting assembly. The discharging mode is time-consuming and labor-consuming, and the discharging efficiency of the austenite-bainite rolling balls is reduced.

The invention discloses a high-toughness corrosion-resistant pearlite steel wire with an adjustable honeycomb structure characteristic as well as a preparation method and application of the high-toughness corrosion-resistant pearlite steel wire, and belongs to the technical field of pearlite steel wire processing. The surface of the steel wire is provided with an aluminum alloy coating which is metallurgically bonded with a base body and has the thickness of 8-10 microns; the steel wire is subjected to ultrasonic treatment to generate a structure with a honeycomb characteristic, and the obtained cementite lamella serves as a hard phase to form a regular'honeycomb wall ', so that a core supporting effect is achieved; the ferrite serving as a plastic phase is coordinated and deformed under the action of external force by forming a honeycomb unit with uniform size, so that more energy is absorbed and crack propagation is hindered; and an Al2O3 protective film is instantaneously formed on the surface of the aluminum alloy coating, so that the aluminum alloy coating has excellent corrosion resistance and better mechanical properties. The Vickers hardness of the aluminum alloy reaches up to 830-850 HV < 0.1 >, the tensile strength of the aluminum alloy reaches 3100-3200 MPa, and the ductility of the aluminum alloy reaches 16-20%.

The present application relates to a kind of high plasticity carbon tool steel wire rod and its manufacturing method, the chemical composition of wire rod and mass percentage include: C:0.51%~0.56%, Si:0.15%~0.25%, Mn:0.45%~0.55%, P≤0.015%, S≤0.015%, the rest is Fe and inevitable impurities, wire rod after spinning is treated by on-line molten salt isostatic toughening, control from high temperature austenite state into sorbite phase region phase transition, isothermal tempering in isothermal interval, promote sorbite sheet layer fuse, toughening stress relief treatment, finally by roller slow cooling, be made into wire rod including microstructure of tempering sorbite, ferrite and fuse sorbite, can improve the plasticity of wire rod, reach tensile strength is 903~952MPa, reduction of area is 53%~58%, reduce material cost and the risk of wire breakage or cracking in tool cold working process, improve tool quality.

The invention relates to the technical field of metal heat treatment, in particular to a steel wire machining quenching device which comprises a box, a pipe for allowing a steel wire to pass through is horizontally and fixedly connected to the outer wall of the box, a feeding port is formed in the top of the pipe, a discharging port is formed in the bottom of the pipe, and a filter screen is fixedly connected to the interior of the pipe; the pipe fitting is sleeved with a heating pipe, one end of the heating pipe is rotationally connected to the outer wall of the box body, a plurality of scraping plates are fixedly connected to the inner wall of the heating pipe, and one side of each scraping plate abuts against the outer wall of the pipe fitting. When the steel wire machining quenching device conducts online quenching machining on a steel wire, molten salt is sprayed on the steel wire from top to bottom so as to prevent impurities floating on the surface of the molten salt from covering the surface of the steel wire, and metal oxides generated in the steel wire heat treatment process are cleaned through the filter screen; and impurities such as metal oxides in the molten salt are prevented from influencing the quenching quality of the steel wire.

The invention discloses a high-strength low-residual-stress wire rod and a preparation method thereof, and belongs to the technical field of wire rod preparation, and the high-strength low-residual-stress wire rod is prepared by optimizing the following steel billet components: 0.01 to 0.022 percent of C, 0.235 to 0.528 percent of Mn, 0.035 to 0.064 percent of Si, 0.001 to 0.002 percent of Li, 0.005 to 0.011 percent of Zr, 0.001 to 0.006 percent of Sr, 0.008 to 0.021 percent of V, 0.006 to 0.013 percent of Nb, 0.01 to 0.025 percent of Ti, 0.02 to 0.1 percent of two or three of Re, Cr and Cu, less than or equal to 0.020 percent of S, less than or equal to 0.020 percent of P and the balance of Fe and inevitable impurities. The prepared wire rod has the characteristics of high strength and low residual stress.

The utility model discloses a heat exchange assembly for improving the cooling efficiency of a salt bath air cooling device, and belongs to the technical field of steel automation. The heat exchange assembly for improving the cooling efficiency of the salt bath air cooling device comprises a supporting plate, a first communicating base and a second communicating base. And an air inlet barrel is fixedly mounted on one side of the upper surface of the supporting plate. According to the heat exchange assembly for improving the cooling efficiency of the salt bath air cooling device, through the design of the vertical air inlet pipeline, the transverse air inlet pipeline, the vertical air outlet pipeline and the transverse air outlet pipeline, the device can exchange heat in the height direction and the length direction, so that the effect of increasing the heat exchange area is achieved, a traditional air cooling exchange pipe is replaced, and the cooling efficiency of the salt bath air cooling device is improved. Due to the design of the multiple exchange pipes, the exchange efficiency can be further improved, it can be guaranteed that when the number of the wires is increased to ten, the temperature fluctuation of the salt bath is small, the process temperature requirement can be met, and the effect of improving the productivity is achieved while the product quality is guaranteed.

The invention relates to a low-residual-torsion-value tire bead steel wire drawing production device and method, and belongs to the technical field of steel wire drawing machining. The low-residual-torsion-value tire bead steel wire drawing production device sequentially comprises a rotary mold device, a heat treatment device, a straightening device and a lead pan tempering device from front to back; the rotating mold device comprises a mold mounting seat and a rotating mold, the straightening device comprises a straightening wheel assembly, the straightening wheel assembly is provided with a straightening wheel capable of moving back and forth, the lead pan tempering device comprises a lead pan, an input driving wheel and a temporary storage device are arranged at the input end of the lead pan, and an output driving wheel is arranged at the output end of the lead pan; the internal stress of the steel wire is effectively released through the rotating die device, the heat treatment device avoids various adverse phenomena such as crossing and doubling of the steel wire, the straightening device further controls the residual torsion value of the steel wire, and the lead pan tempering device improves the tempering treatment efficiency of the steel wire and is beneficial to eliminating the residual internal stress of the steel wire; through improvement of multiple procedures, the residual torsion value of the steel wire is reduced, and the straightness of a product is improved.

The invention discloses a heat treatment process method for a self-aligning roller bearing ring, and belongs to the field of heat treatment processing of self-aligning roller bearing parts. And 2, quenching and heating the ferrule on a roller hearth furnace salt bath martensite quenching production line with a protective atmosphere, and inspecting after salt bath cooling, air cooling, cleaning and rust prevention and salt bath tempering treatment. In the effective wall thickness range of 18-25 mm, the GCr15SiMn high-carbon chromium bearing steel with better hardenability is selected to replace GCr15; and when the sleeve ring is placed, the soft point defect of the contact part of the sleeve ring in the quenching process can be prevented, and the processing yield is improved. Contact type salt bath tempering is adopted, so that the structure is sufficiently transformed, and tempering is sufficient; and the tempering temperature of 200-250 DEG C is adopted, it is guaranteed that the impact toughness of the ferrule is improved by 10%-15% compared with an original technological method, the content of retained austenite in the ferrule after heat treatment is reduced to be within 5%, and it is guaranteed that the dimensional stability of the ferrule is high during subsequent machining and later use.

The utility model belongs to the technical field of industrial heat treatment, and particularly discloses a salt-water separator and a salt bath mesh belt furnace. A salt-water mixture enters the shell through the salt-water mixture inlet, the heating unit heats the salt-water mixture and separates water vapor and liquid salt, the liquid salt is discharged through the salt outlet, the water vapor is discharged to the condensation cavity through the water vapor outlet and the vapor output pipe, and cooling liquid is arranged in the liquid cooling cavity. The water vapor in the condensation cavity is liquefied into condensed water in a liquid cooling mode, the cooling structure is simple, and the cooling cost is low; the condensation cavity and the liquid cooling cavity are both of an arc-shaped structure, the inner arc-shaped wall of the liquid cooling cavity is attached to the outer arc-shaped wall of the condensation cavity, the cooling area is increased, the water vapor cooling speed is increased, condensate water converges to the two ends of the condensation cavity through the gravity of the condensate water, and the condensate water is discharged through condensate water discharging openings formed in the two ends of the condensation cavity. Power components such as a water pump for promoting condensate water to be discharged are not needed, so that the equipment cost and the later maintenance cost are reduced.

The invention provides a wire rod for a high-fatigue steel strand and a preparation method of the wire rod. The wire rod comprises the following components in percentage by weight: 0.77-0.87% of C; 0.20%-1.0% of Si; 0.60% to 0.90% of Mn; cr: 0.02 to 0.30%; 0.01 to 0.03 percent of Ti; n: 0.004 to 0.008%; and the balance of iron and impurities. By controlling the components of the wire rod and combining with the preparation process to control the internal phase transition temperature and the surface layer tempering temperature of the wire rod, the double-phase structure of the surface layer tempered sorbite and the internal sorbite is obtained, and the double-phase structure makes the hardness of the surface layer not higher than that of the interior after cold drawing of the steel wire by utilizing the characteristic that the work hardening rate of the tempered structure is low; and meanwhile, the strength of the steel wire is not influenced, so that the fatigue performance of the steel strand can be obviously improved.

This invention provides a high-strength steel with a low yield strength ratio of 1100MPa and its production method. The steel plate has the following chemical composition by mass percentage: C 0.15~0.17%, Si 0.58~0.6%, Mn 2.53~2.6%, Cr 0.53~0.8%, Ni 1.44~1.6%, Mo 0.2~0.6%, Nb 0.052~0.08%, V 0.02~0.08%, Ti 0.019~0.03%, Al 0.01~0.05%, Cu 0.83~1.5%, with the balance being Fe and unavoidable impurities. The steel plate has a yield strength ≥1100MPa, a yield strength ratio ≤0.88, an elongation ≥14%, and an impact energy ≥30J at -40℃. The finished steel plate has a thickness of 15mm and a microstructure of tempered lath martensite. The high-strength steel plate of this invention, with a yield strength ≥1100MPa, yield strength ratio ≤0.88, elongation ≥14%, and impact energy ≥30J at -40℃, exhibits a low yield-to-tensile ratio. The advantage of this invention lies in the fact that the salt bath Q&P heat treatment process achieves a good balance between high strength and a low yield-to-tensile ratio.

The invention relates to the technical field of grinding ball steel, and discloses a grinding ball steel production process, the heat treatment is the heating key of steel billets, the heating quality directly affects the quality of steel balls, impurities in a hearth need to be removed before charging to ensure that the surfaces of the billets heated in an electric furnace are not contaminated by oil stains, and the heat treatment is performed for ensuring that the billets are uniformly heated. A cushion block needs to be additionally arranged on a large blank, a certain distance needs to be kept between the blanks, the blanks need to be arranged in order when necessary, flames are not allowed to be directly jetted on the surfaces of the blanks or shielding measures are adopted to prevent metal from being overburnt when the blanks are heated in an open flame furnace, and a non-oxidation or less-oxidation heating method needs to be adopted for heating the precision forging blanks. Blank heating temperature and heating time should be carried out according to technological procedure requirements of corresponding forge pieces, heating records should be made in the whole blank heating process so as to be archived for future reference, the thickness of oxide skin and the depth of a decarburized layer should meet the technological requirements of the forge pieces, and the phenomena of overheating, overburning, internal cracks and the like are not allowed to occur in blank heating.

The present invention relates to an alloy steel product prepared by a method comprising the following steps: 1) forging a raw alloy steel; 2) subjecting the forged product to a multi-element co-penetration treatment; and 3) quenching the product after the multi-element co-penetration treatment. The raw alloy steel comprises, by mass percentage, C: 0.2-0.6%, Si: 0.3-0.6%, Mn: 4-8%, Ni: 0.5-1%, Cr: 0.2-0.8%, B: 0.001-0.005%, Ti: 0.1-0.5%, Al: 0.03-0.1%, S: ≤0.015%, P: ≤0.015%, with the remainder being Fe and unavoidable impurities. The alloy steel product has high surface hardness, good wear resistance, and high core toughness, and is suitable for use as bucket teeth for excavators, particularly conical bucket teeth.

The invention discloses an ultrahigh corrosion-resistant retard-bonded prestressed tendon. The prestressed tendon comprises a sleeve, a plurality of reinforcing ribs and a plurality of reinforcing ribs, the steel strand is arranged in the sleeve and extends in the axial direction of the sleeve, a gap is formed between the steel strand and the inner wall of the sleeve, the tensile strength of the steel strand reaches 1860 Mpa or above, the minimum value of the stress corrosion test time of the steel strand in the solution A reaches 5 hours or above, and the median value of the stress corrosion test time of the steel strand in the solution A reaches 8 hours or above; and the slow bonding layer is arranged in a gap between the sleeve and the steel strand. The service life of the prestressed part is further prolonged by selecting the steel strand with higher stress corrosion resistance on the aspect of material intrinsic and adopting a combined slow-bonding protection measure, and the safety performance of the prestressed part within the designed service life is improved; practical reference basis is provided for application of the prestress technology and the retard-bonded prestressed tendon with higher corrosion resistance in the fields of concrete structure engineering and wind power technology.

The invention relates to the technical field of heat treatment isothermal tempering, in particular to a heat treatment salt bath isothermal tempering device and a using method, and the heat treatment salt bath isothermal tempering device comprises a shell, an outer heat preservation layer, a salt bath system, a salt guiding assembly, a salt supplementing pipeline, an air cooling system, a temperature thermocouple, a liquid level control system, a hanging basket and a heating system; the shell is arranged on a horizontal plane, an air inlet pipeline is arranged at the head end of the shell, and an air outlet pipeline is arranged at the tail end; the outer insulating layer is arranged on the outer wall of the shell; the salt bath system is provided with a salt bath tank, the salt bath tank is arranged in the shell, and a stirring assembly is arranged in the salt bath tank. According to the method, unique thermal physical properties of a molten salt medium are utilized, inherent defects of a traditional tempering method are overcome, tempering treatment is carried out at the accurate, uniform and constant temperature, and therefore better, more stable and more reliable metal material performance is obtained.

A salt bath heat treatment device (10) is provided with: a salt bath tank (1) for accommodating a nitrate bath containing molten nitrate so as to cool a metal member during constant-temperature heat treatment; the water adding device (2) is used for adding water into the nitrate bath in the salt bath tank (1); a humidity detection device (5) that includes a humidity sensor (53a) that outputs a signal corresponding to the humidity caused by water vapor generated from the nitrate bath to which water has been added by the water addition device (2); and a control device (100) configured to control the water addition device (2) so as to adjust the amount of water added to the nitrate bath on the basis of a signal output from the humidity sensor (53a) of the humidity detection device (5).