31results about How to "Good Phosphate Film" patented technology

The invention discloses a preparation method of a fastening bolt for an automobile wheel. The preparation method comprises the following processing steps: a, casting a raw material, wherein the raw material comprises the following chemical components in percentage by weight: 0.4 to 0.8% of C, 0.02 to 0.05% of Si, 0.18 to 0.21% of Mn, 0.16 to 0.18% of P, 0.05 to 0.07% of S, 0.05 to 0.15% of Cr, 0.05 to 0.12% of Ti, 0.11 to 0.13% of Cu, 0.01 to 0.02% of Al, 0.02 to 0.03% of Mg, and the balance of iron; and b, scouring the casted and formed rod material; carrying out line drawing on the rod material according to the requirement of the line diameter of the bolt, so that the rod material shrinks to the line diameter required by the bolt; cutting the rod material which is shrunk to the required line diameter to the length required by the bolt; placing the cut rod material into a die cavity at normal temperature; and using upsetting force to enable the dimensions of a head part and a rod part of the rod material to reach the requirements of the bolt. According to the preparation method of the fastening bolt for the automobile wheel, the bolt is processed by cold extruding process, so that the strength of the bolt is improved, the hardness value and the strength value required by the 12.9 high-strength bolt can be realized, and the delayed fracture and the fatigue fracture of the bolt at high strength can be solved; the fastening bolt is reliable in connection and hardly broken during use, prolongs the service life, and meets the usage demand of various industries in the society to high-strength bolts.

The invention discloses a preparation method of a high-strength T-shaped bolt. The preparation method is mainly characterized in that machining steps comprise T-shaped rod material casting and the like. The T-shaped rod material casting comprises that 12-14 parts by weight of waste iron are first fed into a medium frequency furnace to be melted into molten iron, when temperature inside the medium frequency furnace rises to 1000-1200 DEG C, 30-35 parts by weight of steel ingot, 30-35 parts by weight of cast iron and 12-16 parts by weight of foundry returns are then fed into the molten iron, and at the same time, a layer of warm-keeping covering agent is sprinkled on the surface of the solution for covering, then slagging is conducted, and when temperature inside the medium frequency furnace rises to 1400 DEG C for discharging, pouring is conducted. According to the preparation method of the high-strength T-shaped bolt, cold extruding technology bolt machining is adopted, so that the strength of the bolt is improved, a hardness value and a strength value needed by the high-strength bolt are achieved, and the problems of delayed fracture and fatigue fracture of the bolt under high strength are solved, and in the use process, connection is reliable, the bolt is not prone to fracture, service life of the bolt is prolonged, and use demands to the high-strength bolt in all industries in the society are satisfied.

The invention discloses a preparation method of a fracture-resistant steel rope bolt. The process includes following steps: a. casting rod material, wherein a blank of the rod material comprises, in terms of chemical component, by weight, 0.132%-0.260% of C, 0.62%-1.30% of Si, 0.25%-0.35% of Mn, 0.010%-0.030% of P, 0.010%-0.030% of S, 1.10%-1.50% of Cr, trace quantity-0.0018% of B, 0.012%-0.030% of Cu, and the balances are Fe and inevitable impurities; b. washing the rod material after casting molding in acid, conducting thread drawing for the rod material according to the requirement of thread diameter of the bolt to enable the rod material to shrink to the required thread diameter, cutting the rod material after thread diameter shrinks to the required length of the bolt, placing the cutting-off rod material into a mould shaped cavity which is covered by plant ashes at normal temperature, enabling the rod material to form a required head part and required size of a rod part of the bolt by applying upset forging force, and making screw threads on the periphery face of the rod part of the rod material through turning by using a precision lathe. According to the preparation method of the fracture-resistant steel rope bolt, cold extrusion process is applied to process the bolt, so that the strength of the bolt is improved, required hardness and strength of a high-strength bolt are reached, and the problem that delayed fracture and fatigue fracture of the bolt under high strength is solved. The bolt is reliable to use in connection, not easy to break, and the service life of the bolt is prolonged.

The invention discloses a preparation method of a high-strength steel cable bolt. The method includes the following steps: casting a rod material, throwing 10-14 parts by weight of waste steel into a medium frequency furnace, enabling the steel to be melted into liquid steel, adding a carbon addition agent, throwing 30-35 parts by weight of steel ingot, 30-35 parts by weight of cast iron and 12-16 parts by weight of returns into the medium frequency furnace after temperature in the medium frequency furnace is increased to 1120-1220 DEG C, conducting slagging and adding 0.4-0.6 part by weight of copper and liquid iron into a ladle to conduct pouring when temperature in the medium frequency furnace increases to 1450 DEG C and the iron is discharged. The preparation method of the high-strength steel cable bolt adopts the cold extrusion process to process the bolt, improves bolt strength, achieves the hardness and the strength required by 12.9 high-strength bolt, resolves the problems of delaying breaking and fatigue breaking of the bolt under high strength, prolongs service life of the bolt due to the fact that the bolt is reliable in connection and not easy to break in use, and meets using requirements of social industries for the high-strength bolt.

The invention discloses a method for machining a high-strength U-shaped bolt. The method comprises the following steps of: a, casting a U-shaped rod blank, and controlling the weight percentage of each chemical component of the rod blank to meet the following requirements: 0.28 to 0.35 percent of C, 0.25 to 0.35 percent of Mn, 0.05 to 0.09 percent of V, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 percent of P, less than or equal to 0.035 percent of S, 0.55 to 1.20 percent of Ni, 0.35 to 0.45 percent of Co, 0.20 to 0.30 percent of Sn, less than or equal to 0.20 percent of Al and the balance of iron; and b, forging a cast U-shaped rod at the temperature of between 650 and 700 DEG C for not more than 25 times, wherein a thin layer of graphite powder is coated on the inner wall of an impression of a forging die, and the granularity of the graphite powder is controlled to be 200 to 300 meshes; and turning an external thread of the bolt by using a precision lathe after forging. According to the method for machining the high-strength U-shaped bolt, the bolt is machined by adopting a cold extrusion process, so that the strength of the bolt is improved, the hardness value and the strength value required by the 12.9 high-strength bolt are achieved, the problems of delayed fracture and fatigue fracture of the bolt under high strength are solved, the bolt is reliable in connection during use and difficult to break, the service life of the bolt is prolonged, and the using requirement of each industry in the society for the high-strength bolt is met.

The invention discloses a preparation method of a high-strength aluminum alloy flange bolt. Machining steps comprise rod material casting and the like. The rod material casting comprises that 11-14 parts by weight of waste aluminum sectional materials are first fed into a medium frequency furnace to be melted into molten steel, carbon adding agents are then added into the molten steel, when temperature inside the medium frequency furnace rises to 650-700 DEG C, 32-42 parts by weight of A356 aluminium ingot, 30-35 parts by weight of cast iron and 12-16 parts by weight of foundry returns are then fed and at the same time, a layer of warm-keeping covering agent is sprinkled on the surface of the solution for covering, then slagging is conducted, after the slagging, alloy is added, and when temperature inside the medium frequency furnace rises to 1400 DEG C for discharging, pouring is conducted. According to the preparation method of the high-strength aluminum alloy flange bolt, cold extruding technology is adopted to machine the bolt, so that the strength of the bolt is improved, a hardness value and a strength value needed by the high-strength bolt are satisfied, and the problems of delayed fracture and fatigue fracture of the bolt under high strength are solved, and in the use process, connection is reliable, the bolt is not prone to fracture, service life of the bolt is prolonged, and use demands to the high-strength bolt in all industries in the society are satisfied.

The invention discloses a processing method for a high-class bolt. The processing method comprises the following steps: a) casting a rod blank and controlling the weight percent of all chemical components of the rod blank as follows: 0.27-0.34% of C, 0.45-0.65% of Mn, 0.05-0.15% of V, 0.15-0.35% of Si, 0.01-0.04% of W, less than or equal to 0.025% of P, less than or equal to 0.025% of S, 1.55-2.00% of Ni, 0.65-0.95% of Co, 0.20-0.30% of Sn and less than or equal to 0.20% of Cu. According to the processing method for the high-class bolt provided by the invention, a cold extrusion process is adopted for processing the bolt, so that the strength of the bolt is increased, the hardness value and strength value required by the bolt with the strength being 12.9 are achieved, the problems of delay breakage and fatigue breakage of the bolt under high strength are solved, the connection is reliable during a use process, the bolt is difficult to break, the service life of the bolt is prolonged and the use requirement for the high-strength bolt in various industries is met.

The invention discloses a method for machining a T-shaped bolt. The method comprises the following steps of: a) casting a T-shaped rod material blank and controlling the weight percentage of all chemical components of the rod material blank to ensure that the rod material blank comprises 0.28 to 0.35 percent of C, 0.25 to 0.35 percent of Mn, 0.05 to 0.09 percent of V, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 percent of P, less than or equal to 0.035 percent of S, 0.55 to 1.20 percent of Ni, 0.35 to 0.45 percent of Co, 0.20 to 0.30 percent of Sb and less than or equal to 0.20 percent of Cu; according to the method for machining the T-shaped bolt, the bolt is machined by a cold extruding process, so that the intensity of the bolt is improved, the hardness value and the intensity value required by a 12.9 high-intensity bolt can be acquired, and the delayed fracture and the fatigue crack of the bolt under high intensity can be avoided; and during use, the bolt is reliable in connection, is not prone to break, and meets the using requirements of all industries in society on the high-intensity bolt; and the service life of the bolt is prolonged.

The invention discloses a method for machining a high-strength double end bolt. The method comprises the following steps of: a, manufacturing a rod blank, and controlling the weight percentage of each chemical component of the rod blank to meet the following requirements: 0.28 to 0.35 percent of C, 0.25 to 0.35 percent of Mn, 0.05 to 0.09 percent of V, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 percent of P, less than or equal to 0.035 percent of S, 0.55 to 1.20 percent of Ni, 0.35 to 0.45 percent of Co, 0.20 to 0.30 percent of Sb and less than or equal to 0.20 percent of Cu; and b, forging a cast rod at the temperature of between 850 and 800 DEG C for not more than 20 times, wherein a thin layer of fly ash is coated on the inner wall of an impression of a forging die; and turning an external thread at each of two ends of the bolt by using a precision lathe after forging. According to the method for machining the high-strength double end bolt, the bolt is machined by adopting a cold extrusion process, so that the strength of the bolt is improved, the hardness value and the strength value required by the 12.9 high-strength bolt are achieved, the problems of delayed fracture and fatigue fracture of the bolt under high strength are solved, the bolt is reliable in connection during use and difficult to break, the service life of the bolt is prolonged, and the using requirement of each industry in the society for the high-strength bolt is met.

The invention discloses a method for forging a torsional shear type high-strength bolt. The method comprises the step of: manufacturing a rod blank by a casting process, wherein the rod blank comprises the following chemical ingredients in percentage by weight: 0.25 to 0.35 percent of C, 0.15 to 0.25 percent of Mn, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 and more than or equal to 0.015 percent of P, less than or equal to 0.035 and more than or equal to 0.015 percent of S, 0.15 to 0.20 percent of Ni, 0.025 to 0.045 percent of Zn, 0.02 to 0.03 percent of Sn, less than or equal to 0.02 percent of Cr and the balance of Fe. According to the method for forging the torsional shear type high-strength bolt, the bolt is machined by using a cold extrusion process, so that the strength of the bolt is enhanced, a hardness value and a strength value which are required by the high-strength bolt of which the strength is 12.9 are reached, and the delayed breakage and fatigue breakage of the bolt are avoided under high strength; and the torsional shear type high-strength bolt is reliable in connection and difficult to break in the using process, so that the service life of the bolt is prolonged, and the using demand of each industry in society on the high-strength bolt is met.

The invention discloses a processing method for a high-class bolt. The processing method comprises the following steps: a) casting a rod blank and controlling the weight percent of all chemical components of the rod blank as follows: 0.27-0.34% of C, 0.45-0.65% of Mn, 0.05-0.15% of V, 0.15-0.35% of Si, 0.01-0.04% of W, less than or equal to 0.025% of P, less than or equal to 0.025% of S, 1.55-2.00% of Ni, 0.65-0.95% of Co, 0.20-0.30% of Sn and less than or equal to 0.20% of Cu. According to the processing method for the high-class bolt provided by the invention, a cold extrusion process is adopted for processing the bolt, so that the strength of the bolt is increased, the hardness value and strength value required by the bolt with the strength being 12.9 are achieved, the problems of delay breakage and fatigue breakage of the bolt under high strength are solved, the connection is reliable during a use process, the bolt is difficult to break, the service life of the bolt is prolonged and the use requirement for the high-strength bolt in various industries is met.

The invention discloses a method for forging a fracture-resistant bolt. The method comprises the following steps of: a) casting a U-shaped rod material blank, and controlling the weight percentage of all chemical components of the rod material blank to ensure that the fracture-resistant bolt comprises 0.28 to 0.35 percent of C, 0.25 to 0.35 percent of Mn, 0.05 to 0.09 percent of V, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 percent of P, less than or equal to 0.035 percent of S, 0.55 to 1.20 percent of Ni, 0.35 to 0.45 percent of Co, 0.20 to 0.30 percent of Sn, and less than or equal to 0.20 percent of Al; and b) forging and forming the U-shaped rod material formed by forging, wherein the forging temperature is controlled to be 650 to 700 DEG C, thin-layered graphite powder covers on the inner wall of an impression of the forging die, the particle size of the graphite powder is controlled to be 200 to 300 meshes, and the forging frequency is less than or equal to 25 times, and turning an outer thread of the bolt by using a fine turning lathe after forging and forming. According to the method for forging the fracture-resistant bolt, the bolt is machined by a cold extruding process, so that the intensity of the bolt is improved, the harness value and the intensity value which are required by a 12.9 high-intensity bolt can be acquired, and the delayed fracture and the fatigue fracture of the bolt under high intensity are avoided; during use, the bolt is reliable in connection, is not prone to break, and meets the using requirements of all industries in the society on the high-intensity bolt; and the service life of the bolt is prolonged.

The invention discloses a preparation method of a fastening bolt for an automobile wheel. The preparation method comprises the following processing steps: a, casting a raw material, wherein the raw material comprises the following chemical components in percentage by weight: 0.4 to 0.8% of C, 0.02 to 0.05% of Si, 0.18 to 0.21% of Mn, 0.16 to 0.18% of P, 0.05 to 0.07% of S, 0.05 to 0.15% of Cr, 0.05 to 0.12% of Ti, 0.11 to 0.13% of Cu, 0.01 to 0.02% of Al, 0.02 to 0.03% of Mg, and the balance of iron; and b, scouring the casted and formed rod material; carrying out line drawing on the rod material according to the requirement of the line diameter of the bolt, so that the rod material shrinks to the line diameter required by the bolt; cutting the rod material which is shrunk to the required line diameter to the length required by the bolt; placing the cut rod material into a die cavity at normal temperature; and using upsetting force to enable the dimensions of a head part and a rod part of the rod material to reach the requirements of the bolt. According to the preparation method of the fastening bolt for the automobile wheel, the bolt is processed by cold extruding process, so that the strength of the bolt is improved, the hardness value and the strength value required by the 12.9 high-strength bolt can be realized, and the delayed fracture and the fatigue fracture of the bolt at high strength can be solved; the fastening bolt is reliable in connection and hardly broken during use, prolongs the service life, and meets the usage demand of various industries in the society to high-strength bolts.

The invention discloses a method for manufacturing an abrasion-resistant U-shaped bolt. Machining steps include: casting a U-shaped rod, by weight, adding 11-14 parts of scrap steel into a medium frequency furnace to melt to form molten steel, adding carburant, when the temperature in the medium frequency furnace rises to 1120-1220 DEG C, adding 0.1-0.2 part of molybdenum, 0.2-0.3 part of magnesium ingot, 5-7 parts of scrap aluminum, 32-34 parts of steel ingot, 30-35 parts of pig iron and 12-16 parts of foundry returns, simultaneously scattering a layer of heat preservation covering agent on the surface of the melt and covering, slagging, after slagging, adding 0.6-0.9 part of ferromanganese and 2-3 parts of ferrosilicon alloy, when the temperature in the medium frequency furnace rises to 1400 DEG C, withdrawing, adding 0.4-0.6 part of copper along with molten iron into a ladle, and casting. The method adopts cold extrusion process to machine the bolt, the strength of the bolt is improved, hardness and strength required by the 12.9 high-strength bolt are met, and delayed fracture and fatigue fracture of the bolt under high strength are avoided. The bolt is reliable in connection and not prone to break, prolongs service life, and meets use requirements of various industries in society for the high-strength bolt.

The invention discloses a preparation method of a high-strength steel cable bolt. The method includes the following steps: casting a rod material, throwing 10-14 parts by weight of waste steel into a medium frequency furnace, enabling the steel to be melted into liquid steel, adding a carbon addition agent, throwing 30-35 parts by weight of steel ingot, 30-35 parts by weight of cast iron and 12-16 parts by weight of returns into the medium frequency furnace after temperature in the medium frequency furnace is increased to 1120-1220 DEG C, conducting slagging and adding 0.4-0.6 part by weight of copper and liquid iron into a ladle to conduct pouring when temperature in the medium frequency furnace increases to 1450 DEG C and the iron is discharged. The preparation method of the high-strength steel cable bolt adopts the cold extrusion process to process the bolt, improves bolt strength, achieves the hardness and the strength required by 12.9 high-strength bolt, resolves the problems of delaying breaking and fatigue breaking of the bolt under high strength, prolongs service life of the bolt due to the fact that the bolt is reliable in connection and not easy to break in use, and meets using requirements of social industries for the high-strength bolt.

The invention discloses a manufacturing method of an anti-yield foundation bolt. A processing step includes: a, casting a rod blank, wherein the rod blank comprises chemical components, by weight, 0.196%<=C<=0.250%, 0.20%<=Si<=1.90%, 0.35%<=Mn<=1.35%, 0.010%<=P<=0.030%, 0.010%<=S<=0.030%, 1.50%<=Cr<=1.50%, trace amount <=B<=0.0018%, 0.012%<=Cu<=0.030% and the balance Ferrum and inevitable impurities; and cooling temperature of casting molded blank to 350 DEG C, heating to 670-780 DEG C, keeping warm for 3-5 hours, cooling a furnace to 300 DEG C, keeping warm for 3 hours, heating to 650-760 DEG C, keeping warm for 10 hours, cooling to 400 DEG C at 45 DEG C / hour, and cooling to 150 DEG C at 25 DEG C / hour. The manufacturing method of the anti-yield foundation bolt adopts cold extrusion technology bolt processing, improves strength of the bolt, reaches a hardness value and a strength value required by the anti-yield foundation bolt, solves delay breakage and fatigue breakage of the bolt under high strength, is reliable to connect in use and not prone to break, prolongs service life of the bolt, and meets using requirements of various industries in society on high-strength bolts.

The invention discloses a forging method for a foundation bolt. The forging method comprises the following forging steps of: a, preparing rod blanks by a forging process, controlling the chemical components of the rod blanks to satisfy the following requirements in percentage by weight: 0.25%-0.35% of C, 0.15%-0.25% of Mn, 0.15%-0.35% of Si, 0.01%-0.04% of W, P being not less than 0.015% and not more than 0.025%, S being not less than 0.015% and not more than 0.035%, 0.15%-0.20% of Ni, 0.025%-0.045% of Zn, 0.02%-0.03% of Sn, not more than 0.02% o Cr, and the balance of iron. According to the forging method for the foundation bolt disclosed by the invention, the bolt is machined by adopting a cold extrusion process, the strength of the bolt is improved, the needed hardness value and strength value of the 12.9 high-strength bolt are achieved, and delayed fracture and fatigue fracture of the high-strength bolt are solved; and moreover, during the using process, the foundation bolt is reliable in connection and not easy to break, so that the service life of the bolt is prolonged, and the using needs of the high-strength bolt in various industries of the society are satisfied.

The invention discloses a method for forging a flange bolt. The method comprises the following machining steps of: (a) manufacturing a rod blank by a casting process, wherein the rod blank comprises the following chemical ingredients in percentage by weight: 0.25 to 0.35 percent of C, 0.15 to 0.25 percent of Mn, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 and more than or equal to 0.015 percent of P, less than or equal to 0.035 and more than or equal to 0.015 percent of S, 0.15 to 0.20 percent of Ni, 0.025 to 0.045 percent of Ba, 0.02 to 0.03 percent of Sn, less than or equal to 0.02 percent of Mg and the balance of Fe; and (b) casting a cast rod for forming, forging at the temperature of between 600 and 650 DEG C for less than or equal to 25 times, covering thin-layer plant ash on the inner wall of a die cavity of a forging die, and turning the forged rod by utilizing a precision lathe to form external threads of the bolt, wherein the granularity of the plant ash is 200 to 300 meshes. According to the method for forging the flange bolt, the bolt is machined by using a cold extrusion process, so that the strength of the bolt is enhanced, a hardness value and a strength value which are required by the high-strength bolt of which the strength is 12.9 are reached, and the delayed breakage and fatigue breakage of the bolt under high strength are avoided; and the flange bolt is reliable in connection and difficult to break in the using process, so that the service life of the bolt is prolonged, and the using requirement of each industry in society on the high-strength bolt is met.

The invention discloses a preparation method of a lengthened bolt. The preparation method is characterized by comprising the following processing steps of: a, preparing a rod blank through a casting technology, wherein the rod blank comprises the following chemical components in percentage by weight: 0.25%-0.35% of C, 0.08%-0.15% of Mn, 0.05%-0.15% of Si, 0.01%-0.04% of W, no less than 0.015% and no more than 0.025% of P, no less than 0.015% and no more than 0.035% of S, 0.15%-0.20% of Ni, 0.025%-0.045% of Zn, 0.02%-0.03% of Sn, no more than 0.02% of Cr, and the balance of iron. The preparation method of the lengthened bolt disclosed by the invention has the beneficial effect of improving the strength of the bolt by processing the bolt through a cold extrusion process, the hardness value and the strength value required for a 12.9 high-strength bolt are achieved, the problems of delayed fracture and fatigue fracture of the bolt under high strength are solved, the bolt is reliable for connection and less prone to breaking in use, the service life of the bolt is prolonged, and the use requirement on the high-strength bolt in various industries in society is satisfied.

The invention discloses a method for machining a connection rod bolt of a diesel engine. The method comprises the following steps of: manufacturing a rod material blank, and controlling the weight percentage of all chemical components of the rod material blank to ensure that the rod material blank comprises 0.28 to 0.32 percent of C, 0.35 to 0.45 percent of Mn, 0.05 to 0.15 percent of V, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 percent of P, less than or equal to 0.035 percent of S, 0.55 to 1.20 percent of Ni, 0.35 to 0.45 percent of Co, 0.20 to 0.30 percent of Sn and less than or equal to 0.20 percent of Cu. According to the method for machining the connection rod bolt of the diesel engine, the bolt is machined by a cold extruding process, so that the intensity of the bolt is improved, the hardness value and the intensity value which are required by a 12.9 high-intensity bolt can be acquired, and the delayed fracture and fatigue crack of the bolt under high intensity can be overcome; the bolt is reliable in connection during use, and is not prone to break and crack; the service life of the bolt is prolonged; and the using requirements of all industries in society on the high-intensity bolt can be met.

The invention discloses a method for manufacturing bolts for a high-strength excavator. The manufacturing process includes rod material blank casting, wherein the rod material blank comprises the follow chemical components by weight: 0.221%<=C<=0.262%, 0.32%<=Si<=0.90%, 0.25%<=Mn<=0.35%, 0.013%<=P<=0.030%, 0.023%<=S<=0.030%, 20%<=Cr<=1.50%, trace<=B<=0.0018%, 0.012%<=Cu<=0.030%, and the allowance of iron and inevitable impurities. By means of the method, the bolts are processed through a cold extrusion process, so that the strength of the bolts are improved, the required hardness value and strength value of the high-strength bolts can be achieved, delayed fracture and fatigue fracture of the bolts under high strength can be avoided, the bolts can be connected reliably and are not apt to be broken during usage, the service life of the bolts are prolonged, and the using requirements on the high-strength bolts in all industries of the society can be met.

The invention discloses a method for forging a high-strength bolt. The method comprises the following steps of: a, manufacturing a rod blank through a casting process, and controlling the weight percentage of each chemical component of the rod blank to meet the following requirements: 0.28 to 0.35 percent of C, 0.15 to 0.25 percent of Mn, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, more than or equal to 0.015 and less than or equal to 0.025 percent of P, more than or equal to 0.015 and less than or equal to 0.035 percent of S, 0.15 to 0.20 percent of Ni, 0.025 to 0.045 percent of Ba, 0.02 to 0.03 percent of Sn, less than or equal to 0.02 percent of Mg and the balance of iron; and b, forging a cast rod at the temperature of between 630 and 680 DEG C for not more than 25 times, wherein a thin layer of graphite powder is coated on the inner wall of an impression of a forging die, and the granularity of the graphite powder is controlled to be 200 to 300 meshes; and turning an external thread of the bolt by using a precision lathe after forging. According to the method for forging the high-strength bolt, the bolt is machined by adopting a cold extrusion process, so that the strength of the bolt is improved, the hardness value and the strength value required by the 12.9 high-strength bolt are achieved, the problems of delayed fracture and fatigue fracture of the bolt under high strength are solved, the bolt is reliable in connection during use and difficult to break, the service life of the bolt is prolonged, and the using requirement of each industry in the society for the high-strength bolt is met.