CN112536406B - Forging drawing method for avoiding surface cracking - Google Patents
Forging drawing method for avoiding surface cracking Download PDFInfo
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- CN112536406B CN112536406B CN202011341651.9A CN202011341651A CN112536406B CN 112536406 B CN112536406 B CN 112536406B CN 202011341651 A CN202011341651 A CN 202011341651A CN 112536406 B CN112536406 B CN 112536406B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/06—Methods for forging, hammering, or pressing; Special equipment or accessories therefor for performing particular operations
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J1/00—Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
- B21J1/06—Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
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Abstract
The invention belongs to the technical field of metal pressure processing technology, and particularly relates to a forging and drawing method for avoiding surface cracking. The method comprises the following steps: s1: heating the blank; s2: forging a first stroke, rotating for 90 degrees to forge a second stroke, rotating for 90 degrees to forge a third stroke, and so on, and continuing to forge; s3: s2, rotating the forging piece obtained in the step S45 degrees, forging a first stroke, rotating the forging piece by 90 degrees, forging a second stroke, and rotating the forging piece by 90 degrees, and forging a third stroke; and the like, continuing forging; s4: repeatedly forging the blank obtained by the N-1 th forging to the required process size according to the step S3; s5: and finally, rounding and finishing the blank obtained in the step S4 to the required size of the finished product. According to the method disclosed by the invention, the forged high-nitrogen martensitic stainless steel rod has good surface quality, the defect of surface cracking does not occur, and the yield of the high-nitrogen martensitic stainless steel rod in the production process is greatly improved.
Description
Technical Field
The invention belongs to the technical field of metal pressure processing technology, and particularly relates to a forging and drawing method for avoiding surface cracking.
Background
The 30Cr15MoN steel is high-nitrogen martensitic stainless steel, has high strength and hardness, good corrosion resistance, wear resistance and toughness, and is preferentially applied to the fields of large aircrafts, fighters and aerospace due to the excellent performance. The 30Cr15MoN high-nitrogen martensitic stainless steel is a common material for national defense construction with high precision in China, but the production technology is controlled abroad, basically depends on import, has huge cost and faces the risk of forbidden transportation at any time, so that the localization of the steel is particularly necessary.
The 30Cr15MoN steel is used as high-nitrogen steel, has poor thermoplasticity, is easy to crack and uneven in structure in the forging process, and cannot be well solved at the starting stage although the high-nitrogen steel forging process is studied to a certain extent in China. For example: patent application CN106623712A discloses a 40Cr15Mo2VN high nitrogen stainless steel forging forming method, firstly upsetting and punching a 40Cr15Mo2VN steel ingot on a press, then leveling and then rolling and forming on a ring rolling mill, and the patent prevents the temperature from falling below the final forging temperature by strictly controlling the transfer time, the forging time and the forging temperature, thereby avoiding the problem of forging cracking. The method is considered from the aspect of temperature control, although the cracking phenomenon is improved, the applicability is limited, the patent is designed for annular forgings, if bars are to be produced, an elongation process is required to be added, the existing stainless steel bar production mode is generally repeated upsetting and elongation, and square elongation or disordered elongation is adopted for elongation, so that high-nitrogen steel bars are produced, even if the temperature control is optimized, the steel internal stress distribution is uneven in the repeated upsetting and elongation process, the cracking of the steel is also caused, the uneven structure is extremely easy to cause, and the mechanical property of the steel is influenced, so that the yield and the qualification rate of the steel are not high, the forging fire is more, the energy consumption is large, and the production efficiency is low.
Disclosure of Invention
In order to solve the problems, the invention provides a forging and drawing method for avoiding surface cracking, and the steel bar forged by the method can not crack, has uniform steel bar structure, excellent performances in all aspects and high production efficiency, and can meet the requirement of high-precision tip project materials.
In order to achieve the above purpose, the invention adopts the following specific technical scheme:
a forging and drawing method for avoiding surface cracking comprises the following steps:
s1: heating and preserving heat of the blank in a heating furnace, and then discharging and forging;
s2: drawing and forging for the first time; adopting a flat anvil to forge a first stroke, rotating for 90 degrees to forge a second stroke after the first stroke forging is finished, rotating for 90 degrees to forge a third stroke after the second stroke forging is finished, and rotating for 90 degrees to forge a fourth stroke after the third stroke forging is finished; and the like, continuing forging until the forging reaches the required size; when the forging is finished, the cross section of the blank is square column, and any two adjacent faces of the four forged faces are connected through transition faces, namely eight sides are arranged on the cross section of the forging piece when the forging is finished;
s3: drawing and forging for the second time; rotating the forge piece subjected to the first drawing by 45 degrees, forging a first stroke, rotating by 90 degrees after the first stroke forging is finished, forging a second stroke, rotating by 90 degrees after the second stroke forging is finished, forging a third stroke, and rotating by 90 degrees after the third stroke forging is finished, and forging a fourth stroke; and the like, continuing forging until the forging reaches the required size; when the forging is finished, the section of the blank is square and columnar, the size of the blank is smaller than that of the blank obtained after the first drawing forging, and any two adjacent faces of the four forged faces are connected through transition faces, namely eight sides of the forging piece are still arranged on the section when the forging is finished;
s4: drawing and forging for the third time; repeatedly forging the blank obtained in the step S3 to reach the required process size according to the step S3;
s5: drawing and forging for the nth time; repeatedly forging the blank obtained by the N-1 th drawing forging to the required size according to the step S3;
s6: and finally, rolling and finishing the blank obtained in the step S5 to the required size of the finished product.
Preferably, the blank is a steel grade with poor high-temperature plasticity and high heat sensitivity (such as 30Cr15MoN, 0Cr19Ni9N, 4Cr5Mo1SiV1 and the like).
Preferably, the steel grade of the blank is high nitrogen martensitic stainless steel.
Preferably, the high-nitrogen martensitic stainless steel is 30Cr15MoN, and takes 30Cr15MoN as an example, and the blank comprises the following components in percentage by mass: 0.28-0.34% of C, 0.30-0.80% of Si, 0.30-0.60% of Mn, less than or equal to 0.01% of S, less than or equal to 0.02% of P, 14.5-16% of Cr, 0.95-1.1% of Mo, 0.35-0.44% of N, less than or equal to 0.30% of Ni, less than or equal to 0.035% of Al, less than or equal to 0.003% of Ti, less than or equal to 0.25% of Cu, less than or equal to 0.0025% of O, and the balance of iron and unavoidable impurities.
Preferably, the step S1 specifically includes: and heating the steel ingot to 700-720 ℃ for preheating, keeping the temperature for 2 hours, heating to 1200-1250 ℃ at a heating rate of not more than 80 ℃/h, keeping the temperature of the steel ingot, and discharging from the furnace for first drawing forging after the heat-preserving time is not less than 3 hours.
Preferably, after the step S2 is completed, returning the blank to the furnace, heating the blank to 1200-1250 ℃, and taking the blank out of the furnace after the heat preservation time is 2 hours for second drawing forging.
Preferably, after the step S3 is completed, returning the blank to the furnace, heating the blank to 1200-1250 ℃, keeping the temperature for 2 hours, and discharging the blank from the furnace for third drawing forging.
Preferably, in steps S2 to S6, the forging deformation per pass is not more than 70mm.
Preferably, in the step S2/S3/S4/S5/S6, the blank is always rotated in one direction in each drawing forging process, and the blank is rotated by 90 degrees for forging the next stroke after each stroke forging is finished.
Preferably, in step S2/S3/S4/S5/S6, after each drawing forging is completed, the billet must be rotated 45 DEG and then the next drawing forging is performed.
Preferably, in step S2/S3/S4/S5/S6, it is necessary to ensure that the four faces of the forging avoid crossing each time the drawing forging is completed, i.e. the cross section of the blank must remain eight sides each time the drawing forging is completed.
According to the invention, through an octagonal square forging process and combining with an optimized 30Cr15MoN high-nitrogen martensitic stainless steel component formula, the rough blank is manufactured into the stainless steel bar which is free from cracking, uniform in structure and excellent in mechanical property. In order to solve the problems that the existing forging process 30Cr15MoN steel is easy to crack and uneven in structure, the forging mode is optimized, the repeated upsetting and drawing commonly adopted in the prior art is replaced by a non-upsetting direct drawing method, and the drawing adopts a four-octagon method, so that the damage of internal stress is effectively reduced, the cracking problem is relieved, the generation of structural defects is reduced, the forging fire is effectively reduced, and the production efficiency is improved; more optimally, the final forging temperature and the forging deformation of each pass are strictly controlled in the drawing process, so that the possibility of cracking and uneven structure problems is further reduced; the invention optimizes the forging mode and simultaneously performs strict temperature control, and specifically comprises temperature control, heat preservation time setting, tooling and steel ingot preheating and heating speed control of each step of working procedure, so that the stress difference between the inside and the outside of the steel is reduced, the plasticity of the steel is prevented from being reduced, the forging difficulty is further reduced, and the forging effect is ensured.
The invention has the following beneficial effects:
1. the forged 30Cr15MoN high-nitrogen martensitic stainless steel rod has good surface quality, the defect of surface cracking can not occur, and the yield of the 30Cr15MoN high-nitrogen martensitic stainless steel rod in the production process is greatly improved.
2. The 30Cr15MoN high-nitrogen martensitic stainless steel bar forged by the method has uniform metallographic structure, and the unqualified product performance caused by uneven structure is avoided.
3. The forging processing efficiency of the forged 30Cr15MoN high-nitrogen martensitic stainless steel rod is high, the forging production fire time is reduced, and the manufacturing cost is reduced.
Drawings
Fig. 1: in the embodiment 1 of the invention, a drawing process schematic diagram of an octagonal tetragonal method adopted in the forging process is adopted;
fig. 2: example 3 a head micrograph of a steel bar was prepared;
fig. 3: example 3 a photograph of the tail microstructure of a steel bar was made.
Detailed Description
The invention is further described below with reference to the drawings and specific examples.
Example 1
The embodiment provides a forging production process of a 30Cr15MoN high-nitrogen martensitic stainless steel rod, wherein the 30Cr15MoN high-nitrogen martensitic stainless steel comprises the following components in percentage by mass: 0.30% of C, 0.65% of Si, 0.45% of Mn, 0.013% of P, 0.002% of S, 15.1% of Cr, 0.26% of Ni, 1.0% of Mo, 0.06% of Cu, 0.38% of N, and the balance of iron and unavoidable impurities; the forging production process comprises the following steps:
s1, heating a 30Cr15MoN steel ingot with the diameter phi 440mm to 700 ℃ for preheating, keeping the temperature for 2 hours, heating to 1220 ℃ at a heating rate of not more than 80 ℃/h, keeping the temperature of the steel ingot for 5 hours, discharging and forging, and returning the forging to the furnace for 2 hours at the heating temperature of 1220 ℃;
s2, drawing the steel ingot by adopting an octagonal tetragonal method. As shown in fig. 1, the specific operation is as follows:
the forging tool is polished, so that the surface of the forging tool contacted with the steel ingot is smooth and burr-free, and the arc at the edge angle part is in smooth transition; preheating a forging tool to 170 ℃;
directly drawing the round ingot on a 3150 ton hydraulic press without upsetting, using a flat anvil with the width of 800mm, drawing the round ingot by adopting an octagonal tetragonal method, as shown in figure 1, pressing 1/2/3/4 of the four faces of the round ingot, drawing the round ingot to the section size of 330mmx330mm for the first time, and then returning to the furnace for heating; then rotating the workpiece by 45 ︒ to press 5/6/7/8 of the four surfaces, drawing the workpiece for the second time until the cross section size is 250mmx250mm, and returning to the furnace for heating; then the workpiece is rotated by 45 ︒ to press 1/2/3/4 of four surfaces, and is drawn for the third time until the section size is 195mmx195mm (forging is carried out according to 1/2/3/4/1/2/3/4/1/2/3/4 when the four surfaces are forged in the whole forging process, and forging is carried out according to 5/6/7/8/5/6/7/8/5/6/7/8 when the four surfaces are forged by 5/6/7/8, wherein the deformation of each pass of forging is not more than 70mm, the temperature of the surface of the workpiece is not lower than 950 ℃ when the temperature is raised to the surface of the workpiece when the temperature is raised to the temperature, and the temperature is raised and the temperature is kept for 2 hours when the temperature is raised; finally, rounding and finishing to the required size phi 200+/-5 mm of the finished product.
Example 2
A forging production process of a 30Cr15MoN high-nitrogen martensitic stainless steel rod comprises the following components in percentage by mass: 0.28% of C, 0.30% of Si, 0.30% of Mn, 0.009% of P, 0.002% of S, 14.5% of Cr, 0.18% of Ni, 0.95% of Mo, 0.06% of Cu, 0.35% of N, 0.009% of Al, and the balance of iron and unavoidable impurities; the forging production process comprises the following steps:
s1, heating a 30Cr15MoN steel ingot with the diameter phi 440mm to 700 ℃ for preheating, keeping the temperature for 2 hours, heating to 1220 ℃ at a heating rate of not more than 80 ℃/h, keeping the temperature of the steel ingot for 3 hours, discharging and forging, and returning the forging to the furnace for 2 hours at the heating temperature of 1220 ℃;
s2, drawing the steel ingot by adopting an octagonal tetragonal method. As shown in fig. 1, the specific operation is as follows:
the forging tool is polished, so that the surface of the forging tool contacted with the steel ingot is smooth and burr-free, and the arc at the edge angle part is in smooth transition; preheating a forging tool to 180 ℃;
directly drawing the steel wire rod by using a flat anvil with the width of 800mm on a 3150 ton hydraulic press without upsetting, and drawing the steel wire rod by adopting an octagonal tetragonal method, wherein the drawing method is different from that of the embodiment 1 in size, and drawing the steel wire rod for the first time until the section size is 340mmx340mm; drawing for the second time until the cross section size is 280mmx280mm; drawing for the third time until the cross section size is 220mmx220mm; drawing for the fourth time until the cross section size is 175mmx175mm; finally, rounding and finishing to the required size phi 190+/-5 mm of the finished product.
Example 3
A forging production process of a 30Cr15MoN high-nitrogen martensitic stainless steel rod comprises the following components in percentage by mass: 0.34% of C, 0.80% of Si, 0.60% of Mn, 0.02% of P, 0.01% of S, 16% of Cr, 0.25% of Ni, 1.1% of Mo, 0.18% of Cu, 0.44% of N, 0.032% of Al, 0.003% of Ti, 0.0020% of O, and the balance of iron and unavoidable impurities; the forging production process comprises the following steps:
s1, heating a 30Cr15MoN steel ingot with the diameter phi 640mm to 700 ℃ for preheating, keeping the temperature for 2 hours, heating to 1220 ℃ at a heating rate of not more than 80 ℃/h, keeping the temperature of the steel ingot for 5 hours, discharging and forging, and returning the forging to the furnace for 2 hours at the heating temperature of 1220 ℃;
s2, drawing the steel ingot by adopting an octagonal tetragonal method. As shown in fig. 1, the specific operation is as follows:
the forging tool is polished, so that the surface of the forging tool contacted with the steel ingot is smooth and burr-free, and the arc at the edge angle part is in smooth transition; preheating a forging tool to 175 ℃;
directly drawing the steel wire rod by using a flat anvil with the width of 800mm on a 3150 ton hydraulic press without upsetting, and drawing the steel wire rod by adopting an octagonal square method, wherein the drawing method is different from that of the embodiment 1 in terms of size and drawing times, and the drawing is carried out for the first time until the section size reaches 490mmx490mm; drawing for the second time until the cross section size is 400mmx400mm; drawing for the third time to the cross section size of 340mmx340mm, drawing for the fourth time to the cross section size of 280mmx280mm; finally, rounding and finishing to the required size phi 300+/-5 mm of the finished product;
s5, carrying out red sending annealing: heating the forged bar stock to 900 ℃ for heat preservation for 3.5 hours, then cooling to 750 ℃ along with a furnace for heat preservation for 4.5 hours, and turning off the fire, cooling to below 600 ℃ along with the furnace after heat preservation is finished, and discharging and air cooling; and then turning to a finished product with the size phi of 280mm.
The 30Cr15MoN high-nitrogen martensitic stainless steel bars prepared in examples 1-3 were subjected to performance tests, and the test items and test results were as follows:
(1) cracking conditions
The surface of the steel bars prepared in examples 1 to 3 was visually examined, and no cracks were generated.
(2) Tissue state
a. Nonmetallic inclusion
Test methods referring to ASTM E45, method D, test results are as follows:
b. low power tissue
Test methods referring to the correlation profile in ASTM a604, the test results are as follows:
c. microstructure of microstructure
Evaluation was performed according to the correlation profile in SEP 1520, with the following test results:
as shown in fig. 2 and 3, the head and tail microstructure photographs of the steel bar prepared in example 3 show that the head and tail microstructure forms of the steel bar are the same, the grain sizes are consistent, and the uniformity of the microstructure is good.
(3) Mechanical properties
The hardness and tensile strength of the steel bar were tested (annealed hardness by the method specified in GB/T231.1, hardening performance hardness by the method specified in GB/T230.1, tensile strength by the method specified in GB/T228.1) and the test results were as follows:
in conclusion, the 30Cr15MoN high-nitrogen martensitic stainless steel bar forged by the process of the invention cannot crack; no obvious tissue defect, good tissue uniformity and good tissue state; the mechanical property is good.
The present embodiments are merely illustrative of the invention and not limiting of the invention, and any changes made by those skilled in the art after reading the specification of the invention will be protected by the patent laws within the scope of the appended claims.
Claims (4)
1. A forging and drawing method for avoiding surface cracking comprises the following steps:
s1: heating and preserving heat of the blank in a heating furnace, and then discharging and forging;
s2: drawing and forging for the first time; adopting a flat anvil to forge a first stroke, rotating for 90 degrees to forge a second stroke after the first stroke forging is finished, rotating for 90 degrees to forge a third stroke after the second stroke forging is finished, and rotating for 90 degrees to forge a fourth stroke after the third stroke forging is finished; and the like, continuing forging until the forging reaches the required size; when the forging is finished, the cross section of the blank is square column, and any two adjacent faces of the four forged faces are connected through transition faces, namely eight sides are arranged on the cross section of the forging piece when the forging is finished;
s3: drawing and forging for the second time; rotating the forge piece after the last drawing by 45 degrees, forging a first stroke, rotating by 90 degrees after the first stroke forging is finished, forging a second stroke, rotating by 90 degrees after the second stroke forging is finished, forging a third stroke, and rotating by 90 degrees after the third stroke forging is finished, and forging a fourth stroke; and the like, continuing forging until the forging reaches the required size; when the forging is finished, the section of the blank is square and columnar, the size of the blank is smaller than that of the blank obtained after the first drawing forging, and any two adjacent faces of the four forged faces are connected through transition faces, namely eight sides of the forging piece are still arranged on the section when the forging is finished;
s4: drawing and forging for the third time; repeatedly forging the blank obtained in the step S3 to reach the required process size according to the step S3;
s5: drawing and forging for the nth time; repeatedly forging the blank obtained by the N-1 th drawing forging to the required size according to the step S3;
s6: finally, rounding and finishing the blank obtained in the step S5 to the required size of the finished product;
in the steps S2-S5, the deformation of each pass of forging is not more than 70mm;
the blank is 30Cr15MoN and comprises the following components in percentage by mass: 0.28-0.34% of C, 0.30-0.80% of Si, 0.30-0.60% of Mn, less than or equal to 0.01% of S, less than or equal to 0.02% of P, 14.5-16% of Cr, 0.95-1.1% of Mo, 0.35-0.44% of N, less than or equal to 0.30% of Ni, less than or equal to 0.035% of Al, less than or equal to 0.003% of Ti, less than or equal to 0.25% of Cu, less than or equal to 0.0025% of O, and the balance of iron and unavoidable impurities;
the step S1 specifically comprises the following steps: heating the steel ingot to 700-720 ℃ for preheating, keeping the temperature for 2 hours, heating to 1150-1250 ℃ at a heating rate of not more than 80 ℃/h, keeping the temperature of the steel ingot for more than 3 hours, and discharging from a furnace for primary drawing forging;
after the step S2 is completed, returning the blank to the furnace, heating the blank to 1150-1250 ℃, and discharging the blank from the furnace for forging for the second time after the heat preservation time is 2 hours;
and (3) after the step (S3) is completed, returning the blank to the furnace, heating to 1150-1250 ℃, keeping the temperature for 2 hours, and discharging the blank from the furnace for third drawing forging.
2. A method of avoiding surface cracking in a forge drawing process according to claim 1, wherein: in the step S2/S3/S4/S5/S6, the blank always rotates along one direction in each drawing forging process, and the blank is rotated by 90 degrees for forging the next stroke after each stroke forging is finished.
3. A method of avoiding surface cracking in a forge drawing process according to claim 1, wherein: in the step S2/S3/S4/S5/S6, after each drawing forging is completed, the blank must be rotated 45 degrees and then the next drawing forging is performed.
4. A method of avoiding surface cracking in a forge drawing process according to claim 1, wherein: in step S2/S3/S4/S5/S6, it is necessary to ensure that the four faces of the forging avoid crossing each time the drawing forging is completed, i.e., eight sides must be retained in the cross section of the blank each time the drawing forging is completed.
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|---|---|---|---|---|
| JPH07115107B2 (en) * | 1987-03-10 | 1995-12-13 | 大同特殊鋼株式会社 | Forging method |
| JP2007136487A (en) * | 2005-11-16 | 2007-06-07 | Sumitomo Metal Ind Ltd | Method of hot forging |
| UA98409C2 (en) * | 2011-02-14 | 2012-05-10 | Виктор Андреевич ЛАЗОРКИН | Method for producing forgings |
| CN103521670B (en) * | 2013-09-29 | 2016-03-23 | 西北有色金属研究院 | A kind of method improving titanium alloy pulling forging structural homogenity |
| CN108057829B (en) * | 2017-12-14 | 2019-08-09 | 西安赛特思迈钛业有限公司 | A kind of forging method improving titanium alloy forging stock structural homogenity |
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2020
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