52results about How to "Shorten nitriding time" patented technology

The invention discloses a method for producing a low nitriding amount and high magnetic induction oriented silicon steel strip, which comprises the procedures of controlling chemical components in a continuous casting blank, heating to 1,100-1,200 DEG C, hot rolling to form a hot-rolling steel strip with the thickness of 2.0-2.5mm, carrying out two-section normalizing annealing, coldly rolling to form a cold-rolling steel strip with the thickness of 0.23-0.30mm once, and carrying out continuous decarburization processing, continuous nitridation processing and secondary recrystallization annealing processing, conventionally cooling, and the like. In the procedure of the continuous nitridation processing, the N in the cold-rolling steel strip is controlled to be 0.0095-0.0150 in percentage by weight; in the procedure of the secondary recrystallization annealing processing, when the steel strip is heated to 750-1,100 DEG C, the volume rate of N2 is controlled to be 75-90 percent relative to the total volume rate of the N2-H2 atmosphere; and finally, the low nitriding amount and high magnetic induction oriented silicon steel strip is prepared. The invention has proper heat treatment temperature on a plate blank, low manufacture cost and high product quality and can meet the requirements of the high-quality oriented silicon steel for an iron core of a transformer.

The invention relates to a stainless steel ion nitriding process, and in particular relates to an austenitic stainless steel ion nitriding permeation catalyzing process. The process mainly comprises the following steps: 1) washing the surface of a stainless steel surface, and removing the oil stain and impurities on the surface of the workpiece; 2) carrying out pre-oxidation treatment on the stainless steel workpiece; 3) putting the stainless steel workpiece into an ion nitriding furnace after being cooled down, introducing dried hydrogen, building up of luminance and heating up, after reaching a certain temperature, introducing nitrogen, adjusting the ratio of the nitrogen to the hydrogen and the pressure in the furnace, subsequently starting to time, after nitriding for a certain time, closing the ion nitriding furnace and cooling down the workpiece along with the furnace. The austenitic stainless steel treated by using the process can obtain a compound layer which is thicker than that of an ordinary ion nitriding process.

The invention relates to a quick energy-saving gas soft nitriding method for an automobile tire mould. The surface nanometer treatment is that: a common shotblast machine is provided with a set of pressurizing system, and a tire mould workpiece arranged in a charging tray of the shotblast machine with the pressurizing system is subjected to the surface nanometer treatment by a pressurizing shot blasting method; and the quick energy-saving gas soft nitriding method mainly comprises the placement of the workpiece, strong nitriding treatment, diffusion treatment and temperature reduction treatment; in a novel process of pre surface shot blasting nanometer and soft nitriding, because five hours of nitriding time is reduced to achieve the same soft nitriding effect, a great deal of energy consumption is reduced in each nitriding, and obvious economic benefit, social benefit and environmental protection benefit are generated; and the method has the advantages of shortening nitriding cycle and saving energy.

The invention relates to a piston rod and a production method thereof as well as a carbonitriding agent for piston rod surface treatment. The carbonitriding agent comprises the following components by weight percent: 20-24% of urea, 13-15% of thiourea, 10-14% of barium acetate, 24-27% of calcium carbonate, 22-26% of barium carbonate and 4-10% of lithium carbonate. The carbonitriding layer tissue comprises an oxide layer, a tectorium, a compound layer, an Austria layer and a diffusion layer. The carbonitriding agent has the beneficial effects of simple formula and low cost; the piston rod produced by using the carbonitriding agent is smooth in surface, low in roughness and is airproof, the piston rod compound carbonitriding layer is more than 32mu m in thickness and has the characteristics of high corrosion resistance and abrasion resistance, low rejection ratio and long service life; in the piston rod production process, thermal treatment and anti-corrosion treatment are completed once, treatment temperature is between 600 DEG C-700 DEG C, the piston rod production process has the advantage of optimizing the machining process; and nitriding time is shortened to 30-50 minutes, production period is shortened, and production cost is reduced.

The invention discloses a method for gas nitriding sampling detection without shutting down a furnace and a nitriding furnace used thereby, which relate to a gas nitriding sampling detection method and a nitriding furnace used thereby. The method and the nitriding furnace used thereby solve the problems of long nitridation time and high cost for guaranteeing qualified nitridation in a gas nitriding process in the prior art and the problem that a sample cannot be taken from the conventional nitriding furnace under the condition that the furnace is not shut down. The sampling detection method of the invention comprises the following steps of: putting a workpiece, a final detection test sample and a nitriding test sample into a nitriding tank; starting the nitriding furnace, heating and keeping the temperature; taking the nitriding test sample first when the furnace is almost shut down, testing whether the nitriding test sample is qualified, and shutting down the furnace if the nitriding test sample is qualified, or continuously keeping the temperature for initriding if the nitriding test sample is not qualified. A sampling hole of the nitriding furnace of the invention is sealed in and formed in a sampling opening, a sand sealing outer ring is arranged on an upper cover of the nitriding tank, chrome ore is filled in a circular sand sealing slot formed between the inner wall of the sand sealing outer ring and the outer wall of the sampling hole, and a sampling draw wire passes through the chrome ore to suspend the nitriding test sample in the nitriding tank. The method and the nitriding furanace used thereby are applicable in the gas nitriding sampling detection without shutting down the furnace.

The invention discloses a method for preparing Sm2Fe17Nx magnetic powder by taking ammonium carbonate as nitrogen source positive pressure samarium iron nitride alloy. The method comprises the following steps: (1) placing samarium iron alloy powder in a nitriding reaction container, and placing ammonium carbonate solid, a CO2 remover and a drying agent into an ammonia generator in sequence from bottom to top; (2) placing the nitriding reaction container and the ammonia generator in a closed temperature-resistant and pressure-resistant container, and vacuuming the temperature-resistant and pressure-resistant container, wherein the vacuum degree is less than or equal to 0.05 MPa; (3) heating the ammonia generator to thermally decompose the ammonium carbonate; meanwhile heating the nitriding reaction container to 55-100 DEG C, preserving the heat for 10-100 min, then raising the temperature to 300-500 DEG C to perform nitridation and preserving the heat for 1-10 h; cooling to 100-350 DEG C to perform homogenization heat treatment for 1-20 h; finally cooling to room temperature to obtain the Sm2Fe17Nx magnetic powder. According to the method, solid-state ammonium carbonate is heated in the closed container to produce ammonia serving as a nitrogen source so as to uniformly and completely nitrogenize the samarium iron alloy.

The invention provides an ionic nitriding technology assisted by an arc electron source. The ionic nitriding technology assisted by the arc electron source comprises the steps that S1, vacuumizing iscarried out; S2, preheating is carried out; S3, mechanical corrosion is carried out, specifically, argon is pumped to keep vacuum of 0.1-1Pa, the temperature is 200-600 DEG C, a bias voltage is applied between a workpiece and a cavity body, meanwhile, a furnace inner arc electron source is started, a main power supply current is 40-150 A, and arc discharge plasma is generated; an auxiliary anode electrode power supply is turned on, a current is 10-100 A, an electron current in the arc discharge plasma is led to enter a nitriding chamber space, and ironic bombardment mechanical corrosion is carried out on the workpiece for 5-30mins; S4, nitriding is carried out, the furnace inner temperature is kept 200-600 DEG C, the argon and nitrogen are pumped, the vacuum degree is kept at 0.1-1Pa, a voltage is applied between the workpiece and the cavity by a direct current bias voltage power supply, the arc electron source main power supply is turned on, the current is 40-150 A, and the arc discharge plasma is generated; the auxiliary anode electrode power supply is turned on, the current is 10-100A, the electron current of the arc discharge plasma is led to enter the nitriding chamber space,and ironic nitriding is carried out for 0.5-6 hours; and S5, cooling is carried out below 250 DEG C. According to the ionic nitriding technology assisted by the arc electron source, a glow discharge plasma can be enhanced, the reactivity is improved, time is shortened, and gas and energy consumption are reduced.

The invention relates to a method for local ion nitriding of a deep cavity thread of a titanium alloy part, and belongs to the technical field of chemical heat treatment. The method comprises the steps of 1, manufacturing a nitriding tool according to the size and shape of the titanium alloy part; 2, carrying out vacuum annealing treatment on the nitriding tool; 3, wiping the titanium alloy part and the nitriding tool, and blow-drying the titanium alloy part and the nitriding tool through oil-free compressed air or nitrogen; 4, coating the outer wall of the titanium alloy part with the nitriding tool; 5, repeating the step 1 to the step 4 for n times, manufacturing n nitriding tools for coating the titanium alloy part, and enabling the n nitriding tools to be annularly and evenly arrangedon an ionization disc, wherein n is a positive integer; and 6, conducting nitriding treatment on the titanium alloy part. According to the method, the outer surface of the part and the non-nitrided part of the deep cavity are protected against a nitriding layer through tool design, and the temperature, time, atmosphere and electric parameters in the nitriding process are adjusted, so that the whole deep cavity thread obtains the hardness and nitriding depth of the nitriding layer meeting the technical requirements.

The invention discloses a non-brittle nitridation technique for bearing components. According to the technological process, whether the interior of a nitridation furnace leaks air or not is detected firstly, if the air is not leaked, the inflation stage is executed, and then the temperature in the nitridation furnace is increased to 300-350 DEG C; ammonia gas and mixed liquid of a penetrating agent and ammonium chloride concentrated liquid are led into the nitridation furnace, the leading-in speeds of the ammonia gas and the mixed liquid of the penetrating agent and the ammonium chloride concentrated liquid are controlled, and the interior of the furnace continues to be heated till the temperature is 480-500 DEG C; then the leading-in speeds of the ammonia gas and the mixed liquid of the penetrating agent and the ammonium chloride concentrated liquid are increased, and the temperature of the interior of the furnace is increased to 520-550 DEG C; then the inflation speed of the ammonia gas is decreased, and leading-in of the ammonia gas and the mixed liquid of the penetrating agent and the ammonium chloride concentrated liquid is stopped; gas in the furnace is discharged, the pressure in the furnace is controlled, and the temperature in the furnace is decreased to 100-130 DEG C; and finally an ammonia gas bottle and a nitridation furnace gas inlet valve are closed, vacuumizing is conducted, nitrogen gas is led into the furnace to enable the pressure of the interior of the furnace to be positive, the valve is opened, air in the furnace is replaced, the temperature is decreased, and the components are taken out. According to the non-brittle nitridation technique for the bearing components, the problems that as for an existing nitridation technique, the depth of the effective nitridation layer is small, the surface hardness is low, and deformation is large can be effectively solved.

The invention discloses a rapid nitridation preparation method of silicon nitride-boron nitride composite ceramic though reactive sintering. According to the method, a reactive sintering process is adopted, silicon powder and hexagonal boron nitride powder are used as basic raw materials, zirconium oxide powder is used as a catalyst, and yttrium oxide is used as a sintering aid. By utilizing the preparation method disclosed by the invention, a completely nitrided silicon nitride-boron nitride composite material can be prepared in a nitriding and sintering mode within a shorter period of 2.3-5.5 hours; and compared with the conventional process, the method can prepare the silicon nitride-boron nitride composite ceramic which has the advantages of low cost, no size shrinkage and simple process, almost 100% of nitriding rate and excellent mechanical properties, and therefore, the method is suitable for preparing ceramic elements which are complexly shaped and are industrially popularized in large scale, and has remarkable application potentials in practical engineering fields.

The invention provides a rapid nitriding process, and belongs to the technical field of heat treatment. The rapid nitriding process includes: a step A that an electrolyte is added to an electrolysis container, the electrolysis container is then sealed, an electric heating device is arranged on the side portion of the electrolysis container, and a natural gas heating device is arranged at the bottom of the electrolysis container; a step B that external ammonia gas is sent to a gas outlet pipe through a valve, the whole electrolysis container and a whole nitrogenation oven are filled with the ammonia gas in a circulating mode, and then the valve is closed; a step C that a controller controls the natural gas heating device to heat the electrolyte to the boiling point, and then the controller drives an electrolysis rod to work and conduct electrolysis; a step D that the controller controls the natural gas heating device and the electric heating device to conduct alternative heating so that the concentration of nitrogen atoms can be increased; and a step E that an air blower is started so that the ammonia gas and the generated nitrogen atoms can be mixed in water vapor and unceasingly sent to the nitrogenation oven, and closed type circulation is achieved through cooperation of the gas outlet pipe and a gas inlet pipe. Thus, the nitrogen atoms in the nitrogenation oven can be unceasingly supplemented, the nitridation time can be shortened by half, and the defect that the cost is high due to the fact that ammonia gas is unceasingly conveyed in the conventional process is overcome.

The present invention is surface treatment process for cylinder jacket of steel, and belongs to the field of diesel engine accessory making technology. The surface treatment process for cylinder jacket of steel features the soft gas nitridizing process or carbonitriding process. The present invention has reasonable design, and is smart, simple and feasible. The present invention can form one nitride layer with thickness of 0.1-0.4 mm, hardness up to HV600-700, and capacity of raising the mechanical performance and wear resistance of the cylinder jacket, increasing its service life and raising the piston ring matching performance.

The invention discloses a QPQ salt bath nitriding optimization treatment method through laser shock peening. The QPQ salt bath nitriding optimization treatment method comprises the following steps that shock peening treatment is conducted on a workpiece by using a laser device to enable the surface of the workpiece to be dislocated; the workpiece is deoiled, cleaned and dried; the workpiece is putinto a preheating furnace for preheating; the workpiece is put into a direct-current electric field salt bath nitriding furnace, wherein the temperature in the furnace is 500-580 DEG C; the temperature is reduced to 400-450 DEG C for oxidation treatment, and the workpiece is taken out to be cleaned so as to remove CN<-> or CNO<->; the surface of the workpiece is polished; the workpiece is put into the direct-current electric field salt bath nitriding furnace, oxidation treatment is conducted on the workpiece again at the temperature of 300-400 DEG C, and the workpiece is cleaned to remove CN<-> or CNO<->; drying is conducted; and oil immersion is conducted. Compared with the prior art, the QPQ salt bath nitriding optimization treatment method has the advantages that the nitriding efficiency and the nitriding layer thickness are improved, and energy conservation and high efficiency are realized. The invention further provides a QPQ salt bath nitriding optimization treatment device.

The invention relates to a method for continuously producing a manganese nitride product, which is characterized by comprising the following steps: 1) crushing at least one of electrolytic manganese sheet, manganese metal and manganese iron, proportionally adding an adhesive, and pressing into balls; 2) enhancing the temperature and pressure of a pusher kiln or tunnel kiln, wherein the following conditions are always kept: the pressure is positive at 100-10000Pa, and the pusher kiln or tunnel kiln has high temperature at the inlet end and low temperature at the outlet end; 3) putting the material prepared in the step 1) into the pusher kiln or tunnel kiln while introducing nitrogen or an ammonia-nitrogen gas mixture into the pusher kiln or tunnel kiln for 2-8 hours; and 4) discharging the material prepared in the step 3) out of the kiln, and cooling in a nitrogen protective atmosphere.

The invention provides a low-temperature gas nitriding method for high-strength austenitic stainless steel, and relates to the technical field of material surface treatment. The low-temperature gas nitriding method for the high-strength austenitic stainless steel comprises the following steps that the high-strength austenitic stainless steel is subjected to solution treatment, and test steel is obtained; cold rolling deformation treatment is conducted on the test steel to obtain rolled steel; the rolled steel is subjected to surface activating treatment, and activated steel is obtained; the activated steel is subjected to low-temperature gas nitriding treatment, a nitriding layer is formed, and nitrided high-strength austenitic stainless steel is obtained; the temperature of the low-temperature gas nitriding treatment is 300-600 DEG C; and the nitriding time is 6-12 h. Gas nitriding of the high-strength austenitic stainless steel can be achieved under the low-temperature condition, and meanwhile, the nitriding efficiency can be improved; and the thickness of the nitriding layer is increased within a short time, and the mechanical property of the austenitic stainless steel is improved.

The invention discloses a preparation method of aluminum nitride powder. The preparation method comprises the following steps of: mixing aluminum nitrate, calcium nitrate, acetylene black and polyethylene glycol, dissolving in deionized water, uniformly stirring and mixing, heating to 65-75 DEG C, adding urea, dropwise adding an ammonia water solution, heating and keeping for 20-40 minutes, putting into a 1250 DEG C heating furnace, and keeping the temperature for 1-2 hours in a nitrogen atmosphere to obtain a precursor; mechanically mixing the precursor; putting the mechanically mixed precursor into a microwave high-temperature sintering furnace, and carrying out nitriding treatment to obtain carbon-containing aluminum nitride; and putting the carbon-containing aluminum nitride into a decarburization furnace for decarburization so as to obtain aluminum nitride powder. The prepared aluminum nitride powder has the characteristics of uniform particle size distribution, small particle size, high purity and low impurity oxygen content, the preparation method is simple, the preparation process is easy to operate, and the aluminum nitride powder is suitable for large-scale production andprocessing.

The invention relates to a nitriding method of stainless steel, in particular to a gas nitriding method of 1Cr11MoNiWVNbN, 2Cr12MoV and 2Cr10MoVNbN stainless steel. The purpose of the invention is to solve the problem that when nitriding is conducted on the 1Cr11MoNiWVNbN, 2Cr12MoV and 2Cr10MoVNbN stainless steel through an existing gas nitriding method, the situation that the quality is unqualified is very liable to occur. The nitriding method comprises the steps that the stainless steel is put in a nitriding furnace, and the first section of chlorinating is conducted; the second section of chlorinating is conducted; and chlorine removing is conducted. The method has the advantages of high speed, high efficiency, good quality and the like; the nitriding time is shortened more than one time than that of traditional gas nitriding; the indexes of the layer depth, hardness, crack and the like of nitriding are all meet the technical requirements; and the qualification rate of nitriding reaches 100%. The invention belongs to the technical field of stainless steel nitriding.

The invention discloses a production method for nitrided ferrochromium. The method comprises the steps as follows: (1) lump extra-low-carbon ferrochromium is crushed into fine particles with the particle size small than or equal to 2 mm; (2) nitrogen with the purity higher than 99.999% is introduced into a microwave pushed slab kiln, oxygen in the kiln is exhausted until the oxygen content in the kiln is lower than 100 ppm, and the air pressure in the kiln is kept at 100 KPa-100.1 KPa; (3) crushed raw materials are placed in a mullite sagger containing 5%-80% of silicon carbide, a pure silicon carbide sagger or a silicon carbide and silicon nitride combined sagger; and (4) the materials are preheated, nitrided, melted, sintered, cooled and discharged sequentially in the microwave pushed slab kiln. According to the production method, the nitriding and sintering temperature is low, the product quality is stable, and the nitrogen content is high; the industrial microwave pushed slab kiln has high degree of automation, can perform continuous production and has low operation and maintenance cost; the producing cycle is remarkably shortened by more than 30%; and energy conservation and emission reduction are achieved, and the production environment is clean.

The invention discloses a preparation method of alpha-silicon nitride powder, which comprises the following steps: carrying out ball milling on silicon powder doped with Cr2O3 powder, adding a siliconnitride grinding ball and alcohol; putting the silicon powder into a ball mill for ball milling, carrying out suction filtration on the ball milled Cr2O3 silicon powder, and removing the alcohol in the silicon powder; drying the filtered powder in a vacuum drying oven, and removing residual alcohol; grinding and sieving a sample subjected to vacuum drying to obtain powder with uniform particles;putting the ground silicon powder doped with Cr2O3 into a high-temperature tubular furnace, vacuumizing, introducing a nitrogen-hydrogen mixed gas, raising the temperature to 800 DEG C at less than orequal to 5 DEG C / min, and raising the temperature to 1300-1400 DEG C / min, keeping the temperature for 2-4 hours to obtain the silicon nitride powder. The preparation method has the advantages of lownitriding temperature, low cost and short nitriding period, wherein the prepared alpha-Si3N4 phase is as high as 96 wt% in the prepared power, and the particle size is small, and part of the Si3N4 phase is fibrous.

The invention relates to the technical field of metallurgy, and provides a preparation method of a VN19 vanadium-nitrogen alloy. According to the preparation method, powdery vanadium oxide, silicon dioxide powder, a carbonaceous reducing agent, iron powder and a binder are mixed and then sequentially subjected to ball pressing, drying, vacuum carbonization reduction and nitridation, and the VN19 vanadium-nitrogen alloy is obtained. The silicon dioxide powder is added into the raw materials, the silicon dioxide powder is reduced, and silicon nitride is generated in the nitriding process, so that the nitrogen content of a product is increased. According to the preparation method, carbonization reduction is carried out under the vacuum condition, nitridation is carried out under the high nitrogen pressure, and the VN19 vanadium-nitrogen alloy can be efficiently and rapidly prepared in an energy-saving mode. Furthermore, the trend of nitrogen gas flow in the nitriding process is optimized, and a weak cooling and strong cooling subsection cooling mode is adopted in the cooling process, so that the nitrogen content of the product is increased, heat energy is fully utilized, and the preparation cost is reduced.

The invention provides an energy saving and rapid ion nitriding technology for an alloy steel worm. The technology includes the steps of: first, conducting ultrasonic cleaning on an alloy steel worm workpiece to remove oil stain from the surface of the alloy steel worm workpiece; second, loading the workpiece into an ion nitriding furnace, and then pumping the ion nitriding furnace into a vacuum state; third, powering on the ion nitriding furnace, conducting vacuum pumping to make the furnace pressure lower than 150Pa, introducing 500-600V direct current voltage for arc striking, and performing plasma bombardment on the workpiece surface to remove surface oil stain; fourth, conducting heating to 350DEG C; fifth, introducing a certain amount of air, and performing heat preservation for 2h;sixth, introducing ammonia gas for ion nitriding on the workpiece surface; and seventh, conducting cooling. The technology provided by the invention can save the overall nitriding time by 6h, and shorten the time by 20%, and saves 20%-25% of electric energy and ammonia gas.

The invention relates to a method for continuously producing a manganese nitride product, which comprises the following steps of: crushing electrolytic manganese sheets, manganese metal and ferromanganese, pressing and forming, placing the pressed and formed material in a pushed slab kiln or a tunnel kiln, introducing nitrogen or ammonia-nitrogen mixed gas into the pushed slab kiln or the tunnel kiln, and continuously producing the manganese nitride product. And heating in a pushed slab kiln or a tunnel kiln to 700-1000 DEG C to produce a manganese nitride product. The method has the advantages of no need of vacuumizing, continuous production, low energy consumption, small equipment investment, high production efficiency, short production time and the like. The nitrogen content of the obtained manganese nitride product is about 7-8wt%.

The invention discloses a method for shortening the gas nitriding process time of structural alloy steel, relates to a method for shortening the gas nitriding process time of steel, and aims at solving the problems of long nitriding time and low production efficiency of an existing nitriding process of structural alloy steel. The method comprises the following steps: 1, putting an energizer / sand mixture into an iron bucket; 2, putting a structural alloy steel workpiece and the iron bucket with the energizer / sand mixture into a nitriding tank, sealing a furnace cover, introducing ammonia gas until the volume percent of the ammonia gas in a nitriding tank is 90%, uniformly heating until the temperature of the nitriding tank is 530-540 DEG C, preserving heat for 20 hours wherein the ammonia decomposition rate is 20%-35% and the temperature is 530-540 DEG C, naturally cooling to less than 150 DEG C along with a furnace, and discharging from the furnace to obtain a nitrided structural alloy steel workpiece with the nitriding layer depth of not less than 0.3 mm. The method of a nitriding process of the structural alloy steel can be obtained.

The invention relates to a piston rod and a production method thereof as well as a carbonitriding agent for piston rod surface treatment. The carbonitriding agent comprises the following components by weight percent: 20-24% of urea, 13-15% of thiourea, 10-14% of barium acetate, 24-27% of calcium carbonate, 22-26% of barium carbonate and 4-10% of lithium carbonate. The carbonitriding layer tissue comprises an oxide layer, a tectorium, a compound layer, an Austria layer and a diffusion layer. The carbonitriding agent has the beneficial effects of simple formula and low cost; the piston rod produced by using the carbonitriding agent is smooth in surface, low in roughness and is airproof, the piston rod compound carbonitriding layer is more than 32mu m in thickness and has the characteristics of high corrosion resistance and abrasion resistance, low rejection ratio and long service life; in the piston rod production process, thermal treatment and anti-corrosion treatment are completed once, treatment temperature is between 600 DEG C-700 DEG C, the piston rod production process has the advantage of optimizing the machining process; and nitriding time is shortened to 30-50 minutes, production period is shortened, and production cost is reduced.

The invention discloses a deep level nitriding process for engine cylinder bushes, comprising the procedures of cleaning, charging, ion nitriding and tapping, wherein in the charging procedure, a bottom supporting disk is supported on a cathode disc by using a conductor column, cylinder bushes are uniformly arranged on the bottom supporting disk, a top plate is arranged on the cylinder bushes, and through holes are arranged on the top plate and the bottom supporting disk corresponding to the positions of the cylinder bushes; and in the ion nitriding procedure, arc light starts when the vacuum degree in a furnace reaches 50Pa below and the voltage is set at 650V, then the voltage and the duty cycle are sequentially increased, ammonia gas is fed into the furnace after the voltage is adjusted to 700V and the arc light frequency is reduced, the voltage in the furnace is adjusted to 750V when the arc light basically disappears, the glow is stable and the flow of the ammonia gas is not increased, heat preservation is carried out at 520 DEG C for 15h and 540 DEG C for 25h, the flow of the ammonia gas is 0.5-0.8L / min and the vacuum degree is 500-800Pa, and the temperature of the cylinder bushes are gradually reduced under the glow state, and furnace shutdown, gas cutoff and cooling are carried out after the temperature is reduced to 300 DEG C below. Based on the ion nitriding process disclosed by the invention, the nitriding speed is high, the diffusion layer is deep, and the technical requirements of engine cylinder bushes are met.

The invention relates to a method for shortening the gas nitriding process time of alloy structural steel, which relates to a method for shortening the gas nitriding process time of steel. The purpose of the invention is to solve the problem of long nitriding time and low production efficiency in the existing nitriding process of alloy structural steel. Method: 1. Put the infiltrating agent / sand mixture into the iron drum; 2. Put the alloy structural steel workpiece and the iron drum containing the infiltrating agent / sand mixture in the nitriding tank, seal the furnace cover, and put it into Ammonia, until the volume fraction of ammonia in the nitriding tank is 90%, and then uniformly heated until the temperature of the nitriding tank is 530°C-540°C, and then the ammonia decomposition rate is 20%-35% and the temperature is 530°C-540 ℃ for 20 hours, and then naturally cooled with the furnace until the temperature is lower than 150 ℃, it can be taken out of the furnace, and a nitrided alloy structural steel workpiece with a nitrided layer depth of ≥0.3mm can be obtained. The invention can obtain a method for nitriding process of alloy structural steel.