CN115341075A - Processing technology of cast iron nut - Google Patents

Processing technology of cast iron nut Download PDF

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Publication number
CN115341075A
CN115341075A CN202211116376.XA CN202211116376A CN115341075A CN 115341075 A CN115341075 A CN 115341075A CN 202211116376 A CN202211116376 A CN 202211116376A CN 115341075 A CN115341075 A CN 115341075A
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Prior art keywords
cast iron
iron nut
nut
heat treatment
blank
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CN202211116376.XA
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Chinese (zh)
Inventor
赵灿林
窦金碧
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Wuxi Hongba Mechanical And Electrical Equipment Co ltd
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Wuxi Hongba Mechanical And Electrical Equipment Co ltd
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Priority to CN202211116376.XA priority Critical patent/CN115341075A/en
Publication of CN115341075A publication Critical patent/CN115341075A/en
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/28—Normalising
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/30—Stress-relieving
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
    • 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
    • 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
    • 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
    • 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
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper

Abstract

The invention relates to a processing technology of a cast iron nut. The invention comprises the following steps: turning an outer circle; marking the axis of the screw hole; turning internal threads; checking the precision; heating the heat treatment furnace; heating the heat treatment furnace to 835-870 ℃; normalizing for the first time: putting the cast iron nut semi-finished product into a heat treatment furnace, keeping the temperature for 20-25min, and naturally cooling after the cast iron nut semi-finished product is taken out of the furnace after air cooling; reheating the heat treatment furnace: heating the heat treatment furnace to 835-870 ℃; normalizing for the second time: and putting the cooled cast iron nut semi-finished product subjected to the first normalizing treatment into a heat treatment furnace, wherein the total heating time is 60-65min, keeping the temperature for 20-25min, and naturally cooling the cast iron nut semi-finished product discharged from the furnace after air cooling. The invention not only ensures that the mechanical property of the cast iron nut is not reduced, but also ensures that the processing stress is eliminated, and ensures that the cast iron nut is used in a safe state.

Description

Processing technology of cast iron nut
Technical Field
The invention relates to the technical field of heat treatment of cast iron nuts, in particular to a secondary normalizing process of a cast iron nut.
Background
The trapezoidal nut structure for being matched with the trapezoidal screw rod to convert the rotary force into the push-pull force is called as a cast iron nut for short, and the cast iron nut is a mechanical mechanism trapezoidal nut for converting the rotary force into the push-pull force. However, the cast iron nut is a vulnerable part in a transmission mechanism, and the requirement on the performance of the nut is high in the process of converting the rotary force into the push-pull force. Therefore, it is very important to improve the mechanical properties of the cast iron nut, and it is an important prerequisite to ensure good performance of the cast iron nut to ensure the manufacturing quality of the cast iron nut.
Conventionally, after the cast iron nut is made of 40Mn2 steel, the trapezoidal nut needs to be aged to relieve internal stress. If this internal stress is not timely eliminated, the mechanical properties of the nut do not meet the production requirements. Therefore, the cast iron nut needs to be subjected to an integral heat treatment to eliminate residual stress generated during the manufacturing of the cast iron nut and to increase the mechanical properties of the nut. However, too high or too low temperature of the heat treatment can affect the material structure of the cast iron nut, and further affect the mechanical properties of the cast iron nut. In addition, if the heat treatment process is not adopted properly, the mechanical properties of the cast iron nut are seriously attenuated, thereby causing the mechanical properties of the cast iron nut to be degraded.
Disclosure of Invention
The invention aims to solve the problem that the internal stress of a workpiece is not completely eliminated or the mechanical property is seriously attenuated due to unreasonable design of the temperature of a heat treatment process in the prior art, and provides a processing process of a cast iron nut.
In order to solve the technical problem, the invention provides a processing technology of a cast iron nut, which comprises the following steps:
s1: turning the outer circle: after the outer circle of the cast iron nut blank is turned, the diameter of the cast iron nut blank is controlled as follows: 40-40.5mm, length: 45-45.5mm;
s2: scribing a screw hole axis: marking the axis of a screw hole and the central distance dimension line of the blank on the cast iron nut blank, and performing sample punching to punch a central punching hole with the diameter of 2-3 mm;
s3: turning: a turning tool is installed by using the tool setting sample plate, and the tool tip of the turning tool is aligned to the center punching hole of the cast iron nut blank; clamping a cast iron nut blank on a four-jaw independent chuck, ensuring that the parallelism requirement and the distance size between the axis of a screw hole and a bottom plane are kept, turning trapezoidal internal threads, and selecting a cutting speed of less than 5m/min and a back cutting depth of 0.02-0.01 mm when the tooth form of the internal threads is finely turned;
s4: and (3) precision inspection: the semi-finished product of the cast iron nut is matched with a lead screw matched with the size of the inner screw hole of the semi-finished product, the precision of the axial clearance is tested, and the axial clearance is controlled as follows: 0.1-0.3mm;
s5: heating of a first heat treatment furnace: heating the heat treatment furnace to 835-870 ℃;
s6: normalizing for the first time: putting the processed cast iron nut semi-finished product into a heat treatment furnace, heating for 60-65min, keeping the temperature for 20-25min, air-cooling the cast iron nut semi-finished product discharged from the furnace, and naturally cooling;
s7: heating in a second heat treatment furnace: heating the heat treatment furnace to 835-870 ℃;
s8: normalizing for the second time: and putting the cooled cast iron nut semi-finished product subjected to the first normalizing treatment into a heat treatment furnace, heating for 60-65min, keeping the temperature for 20-25min, air-cooling the cast iron nut semi-finished product discharged from the furnace, and naturally cooling.
In one embodiment of the present invention, in step S2, the cast iron nut blank material is 40Mn2 steel, and the material composition thereof by weight percentage is as follows: c:0.37 to 0.44%, si:0.20 to 0.40%, mn:1.40 to 1.80 percent of the total weight of the alloy, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, less than or equal to 0.20 percent of Cu, more than 0.015 percent of Als and the balance of Fe.
In one embodiment of the invention, in step S3, the screw pitch of the lathe is 12mm, the pitch of the turned cast iron nut blank is 5mm, and turning is performed by a back-and-forth turning method.
In one embodiment of the invention, in step S3, two layers of abrasive cloth are padded between the jaws of the four-jaw single-action chuck and the cast iron nut blank, the sand grain surface of the abrasive cloth is not contacted with the surface of the cast iron nut blank, a scribing block of a lathe is arranged on a middle sliding plate, the height of a scriber is adjusted to be equal to the height of the center axis of a tailstock, and then a saddle and the middle sliding plate are moved and the horizontal axis and the vertical axis of the cast iron nut blank are aligned; and (3) clamping the dial indicator on a square tool rest, enabling the measuring head to contact with the bottom plane, firstly aligning the horizontal plane to be in a horizontal position, then moving a saddle leftwards and rightwards to align the bottom plane to be parallel to the axis of the main shaft, enabling the reading of the pointer of the dial indicator to be within 0.05mm, repeating the steps, and clamping the cast iron nut blank to ensure that the parallelism between the axis of the screw hole and the bottom plane is kept to be 0.01-0.05mm and the distance size is 4-5mm.
In one embodiment of the present invention, in step S3, the cast iron nut blank is clamped to the four-jaw independent chuck at a clamping length of 25 to 30mm.
In one embodiment of the present invention, in step S3, an integral internal thread turning tool is selected, the internal thread is turned to a major diameter of 20-20.5mm by using a straight flute tool, and then the tooth surface is turned by using the integral internal thread turning tool.
In an embodiment of the invention, in step S4, the cast iron nut blank is screwed onto the lead screw, and the lead screw is clamped between the two apexes, so that the measuring head of the dial indicator contacts the end surface of the nut, the nut is pushed in the left-right axial direction, and the swing value of the pointer of the dial indicator is not more than 0.1mm, namely the dial indicator is qualified.
In an embodiment of the invention, in step S4, the cast iron nut blank is clamped between two centers, the magnetic force gauge stand is fixed on a saddle of a lathe, so that a measuring head of the dial indicator contacts a bottom plane, a horizontal position of the bottom plane is firstly aligned, then a saddle of the lathe is moved for measurement, and the swing value of a pointer of the dial indicator is not more than 0.08mm, which is qualified.
In one embodiment of the invention, in step S6, the cast iron nut semi-finished product after being discharged is clamped by a three-jaw chuck to freely rotate, and forced air cooling is carried out for 4-6 min.
In one embodiment of the invention, in step S8, the cast iron nut semi-finished product is clamped by a three-jaw chuck to rotate after tapping, and forced air cooling is carried out for 3-4 min.
Compared with the prior art, the technical scheme of the invention has the following advantages:
according to the processing technology of the cast iron nut, compared with the prior art, the mechanical property attenuation amplitude of the cast iron nut after heat treatment is obviously reduced, the elongation and the reduction of area are obviously improved, and compared with the prior art, the comprehensive performance of the cast iron nut after heat treatment is improved.
The microstructure and the grain size of the cast iron nut after heat treatment do not change obviously with the microstructure of 40Mn2 steel, thereby ensuring the use performance of the cast iron nut material. The cast iron nut has more excellent comprehensive mechanical properties by adopting heat treatment processes such as proper heating temperature, heat preservation time, cooling mode and the like.
The invention ensures that all performance indexes of the cast iron nut reach the design and use requirements while eliminating the internal stress of the cast iron nut, thereby ensuring the use performance of the cast iron nut. By selecting the proper heat treatment temperature and the proper heat treatment method selected by the cast iron nut, the invention not only achieves the effect of eliminating stress of the cast iron nut, but also simplifies the production process, thereby saving the heat treatment time and improving the production efficiency.
Drawings
In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which
Fig. 1 is a flow chart of a process for manufacturing a cast iron nut according to the present invention.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.
Example 1
Referring to fig. 1, the processing technology of the cast iron nut of the invention, the cast iron nut is a lead screw trapezoidal nut, and comprises the following steps:
s1: turning the outer circle: after the outer circle of the cast iron nut blank is turned, the diameter of the cast iron nut blank is controlled as follows: 40-40.5mm, length: 45-45.5mm;
s2: scribing a screw hole axis: marking the axis of a screw hole and the central distance dimension line of the blank on the cast iron nut blank, and performing sample punching to punch a central punching hole with the diameter of 2-3 mm;
s3: turning: a turning tool is installed by using the tool setting sample plate, and the tool tip of the turning tool is aligned to the center punching hole of the cast iron nut blank; clamping a cast iron nut blank on a four-jaw independent chuck, ensuring that the parallelism requirement and the distance size between the axis of a screw hole and a bottom plane are kept, turning trapezoidal internal threads, and selecting a cutting speed of less than 5m/min and a back cutting depth of 0.02-0.01 mm when the tooth form of the internal threads is finely turned;
s4: and (3) precision inspection: the semi-finished product of the cast iron nut is matched with a lead screw matched with the size of the inner screw hole of the semi-finished product, the precision of the axial clearance is tested, and the axial clearance is controlled as follows: 0.1-0.3mm;
s5: heating a first heat treatment furnace: heating the heat treatment furnace to 835-870 ℃;
s6: normalizing for the first time: putting the processed cast iron nut semi-finished product into a heat treatment furnace, heating for 60-65min, keeping the temperature for 20-25min, performing air cooling on the cast iron nut semi-finished product discharged from the furnace, and naturally cooling;
s7: heating in a second heat treatment furnace: heating the heat treatment furnace to 835-870 ℃;
s8: normalizing for the second time: and putting the cooled cast iron nut semi-finished product subjected to the first normalizing treatment into a heat treatment furnace, heating for 60-65min, keeping the temperature for 20-25min, air-cooling the cast iron nut semi-finished product discharged from the furnace, and naturally cooling.
Specifically, in step S2, the cast iron nut blank material is 40Mn2 steel, and the material composition thereof in percentage by weight is: c:0.37 to 0.44%, si:0.20 to 0.40%, mn:1.40 to 1.80 percent, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, less than or equal to 0.20 percent of Cu, more than 0.015 percent of Als and the balance of Fe.
Specifically, in the step S3, a CA6140 lathe is adopted, the screw pitch of the screw is 12mm, the screw pitch of the turned cast iron nut blank is 5mm, and the screw pitch and the workpiece pitch cannot be completely removed, so that turning is carried out by adopting a back-and-forth turning method, and the phenomenon of broken thread is avoided.
Specifically, in the step S3, two layers of abrasive cloth are padded between the jaws of the four-jaw single-action chuck and the cast iron nut blank, the sand grain surface of the abrasive cloth is not contacted with the surface of the cast iron nut blank, a scribing disc of the lathe is arranged on a middle sliding plate, the height of a scribing needle equal to the height of the axis of the tip of a tailstock is adjusted, and then a saddle and the middle sliding plate are moved and the horizontal axis and the vertical axis of the cast iron nut blank are aligned; and (3) clamping the dial indicator on a square tool rest, enabling the measuring head to contact with the bottom plane, firstly aligning the horizontal plane to be in a horizontal position, then moving a saddle leftwards and rightwards to align the bottom plane to be parallel to the axis of the main shaft, enabling the reading of the pointer of the dial indicator to be within 0.05mm, repeating the steps, and clamping the cast iron nut blank to ensure that the parallelism between the axis of the screw hole and the bottom plane is kept to be 0.01-0.05mm and the distance size is 4-5mm.
Specifically, in step S3, the cast iron nut blank is clamped to the four-jaw independent chuck at a clamping length of 25 to 30mm.
Specifically, in the step S3, a CA6140 lathe is selected, an integral internal thread turning tool is selected, the internal thread is turned to 20-20.5mm in large diameter by using a straight flute cutter, and then the tooth surface is turned by using the integral internal thread turning tool.
Specifically, in step S4, the cast iron nut blank is screwed onto the lead screw, and the lead screw is clamped between the two center tips, so that the measuring head of the dial indicator contacts with the end surface of the cast iron nut blank, the nut is pushed in the left-right axial direction, and the swing value of the pointer of the dial indicator is not more than 0.1mm, namely the nut is qualified.
Specifically, in the step S4, the cast iron nut blank and the nut are clamped between two centers, the magnetic meter holder is fixed on a sliding saddle of a CA6140 type lathe, a measuring head of the dial indicator contacts with a bottom plane, a transverse horizontal position of the bottom plane is firstly aligned (if necessary, an adjustable support is used for supporting the nut to prevent the horizontal position of the nut from moving), then the sliding saddle of the CA6140 type lathe is moved for measurement, and the condition that the swing value of a pointer of the dial indicator is not more than 0.08mm is met.
Specifically, in step S6, the cast iron nut semi-finished product after being discharged is clamped by a three-jaw chuck to freely rotate, and forced air cooling is carried out for 4-6 min.
Specifically, in step S8, the semi-finished cast iron nut after tapping is clamped by a three-jaw chuck to rotate, and forced air cooling is carried out for 3-4 min.
In this example, a nominal diameter of a trapezoidal thread is 26mm, a thread pitch is 5mm, tr (left-hand) is 26X 5LH (thread axis), and an internal thread is turned to Tr 26X 5LH.
Heating the cast iron nut semi-finished product for 60-65min twice, keeping the temperature for 20-25min, rotating the cast iron nut semi-finished product after discharging, and performing forced air cooling and natural air cooling. So as to refine crystal grains, improve the strength and the low-temperature impact toughness and achieve the aim of strengthening and toughening
Referring to tables I to III, by the treatment, the cast iron nut after the secondary normalizing process is detected, and the mechanical property of the cast iron nut after the heat treatment is obviously reduced compared with the prior art, and the elongation and the reduction of area are both improved, so that the comprehensive performance of the cast iron nut after the heat treatment is improved compared with the prior art. The microstructure and the grain size of the cast iron nut after heat treatment are not obviously changed from the microstructure of 40Mn2 steel, so that the use performance of the cast iron nut material is ensured. The cast iron nut has more excellent comprehensive mechanical properties by controlling the heat treatment process system such as heating temperature, heat preservation time, cooling mode and the like.
Table one: mechanical property meter for cast iron nut treated by the method of the invention
Figure BDA0003845491000000051
Table two: mechanical property meter for cast iron nut treated by conventional method
Figure BDA0003845491000000052
Table 3: mechanical property meter for cast iron nut processed by different normalizing temperatures
Figure BDA0003845491000000053
Figure BDA0003845491000000061
The chemical components and the forced air cooling speed have the greatest influence on the performance when normalizing is studied through production practice. When the carbon content (0.37-0.38%) and manganese content (1.40-1.50%) of the 40Mn2 steel are in the lower limit range, the strength of the cast iron nut is low when the temperature is normalized at high temperature (higher than 25 ℃). Therefore, various manufacturing plants have various regulation and control methods for the cooling speed of the normalizing fire according to production conditions, chemical compositions of steel and different seasons, such as controlling air quantity and air pressure, covering and slowly cooling, increasing and decreasing the arrangement density during cooling, adjusting austenitizing temperature and the like, so as to meet the mechanical property requirements of the cast iron nut. Fragments are formed in a low-temperature (-50 ℃) blasting test of the normalized 40Mn2 cast iron nut, and the shape of the crevasse does not meet the requirement. On the other hand, in the case of C, mn in a low amount (< 0.41% C, < 1.60% Mn), the secondary normalized cast iron nut was free from chipping in the low-temperature explosion test and satisfactory in the shape of the hole.
The invention ensures that all performance indexes of the cast iron nut meet the design and use requirements while eliminating the internal stress of the cast iron nut, thereby ensuring the use performance of the cast iron nut. By selecting the proper heat treatment temperature and the proper heat treatment method selected by the cast iron nut, the invention not only achieves the effect of eliminating stress of the cast iron nut, but also simplifies the production process, thereby saving the heat treatment time and improving the production efficiency.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims (10)

1. The machining process of the cast iron nut is characterized by comprising the following steps of:
s1: turning the outer circle: after the outer circle of the cast iron nut blank is turned, the diameter of the cast iron nut blank is controlled as follows: 40-40.5mm, length: 45-45.5mm;
s2: scribing a screw hole axis: marking the axis of a screw hole and the central distance dimension line of the blank on a cast iron nut blank, and performing proofing and punching to form a central punching hole with the diameter of 2-3 mm;
s3: turning: a turning tool is installed by using the tool setting sample plate, and the tool tip of the turning tool is aligned to the center punching hole of the cast iron nut blank; clamping a cast iron nut blank on a four-jaw independent chuck, ensuring that the parallelism requirement and the distance size between the axis of a screw hole and a bottom plane are kept, turning trapezoidal internal threads, and selecting a cutting speed of less than 5m/min and a back cutting depth of 0.02-0.01 mm when the tooth form of the internal threads is finely turned;
s4: and (3) precision inspection: the semi-finished cast iron nut and the lead screw with the size of the inner screw hole matched with each other are matched with each other, the precision of the axial clearance is tested, and the axial clearance is controlled as follows: 0.1-0.3mm;
s5: heating of a first heat treatment furnace: heating the heat treatment furnace to 835-870 ℃;
s6: normalizing for the first time: putting the processed cast iron nut semi-finished product into a heat treatment furnace, heating for 60-65min, keeping the temperature for 20-25min, air-cooling the cast iron nut semi-finished product discharged from the furnace, and naturally cooling;
s7: heating in a second heat treatment furnace: heating the heat treatment furnace to 835-870 ℃;
s8: normalizing for the second time: and putting the cooled cast iron nut semi-finished product subjected to the first normalizing treatment into a heat treatment furnace, heating for 60-65min, keeping the temperature for 20-25min, air-cooling the cast iron nut semi-finished product discharged from the furnace, and naturally cooling.
2. The processing technology of the cast iron nut as claimed in claim 1, wherein in the step S2, the cast iron nut blank material is 40Mn2 steel, and the material composition of the cast iron nut blank material comprises, by weight: c:0.37 to 0.44%, si:0.20 to 0.40%, mn:1.40 to 1.80 percent of the total weight of the alloy, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, less than or equal to 0.20 percent of Cu, more than 0.015 percent of Als and the balance of Fe.
3. The processing technology of the cast iron nut as claimed in claim 1, wherein in the step S3, the screw pitch of a lathe is 12mm, the pitch of a turned cast iron nut blank is 5mm, and turning is performed by a back-and-forth turning method.
4. The processing technology of the cast iron nut according to the claim 1, characterized in that in the step S3, two layers of abrasive cloth are padded between the jaws of the four-jaw independent chuck and the cast iron nut blank, the sand grain surface of the abrasive cloth is not contacted with the surface of the cast iron nut blank, the scribing block of the lathe is arranged on the middle sliding plate, the height of the scribing needle is adjusted to be equal to the height of the center axis of the tailstock, and then the saddle and the middle sliding plate are moved and the horizontal axis and the vertical axis of the cast iron nut blank are aligned; and (3) clamping the dial indicator on a square tool rest, enabling the measuring head to contact with the bottom plane, firstly aligning the horizontal plane to be in a horizontal position, then moving a saddle leftwards and rightwards to align the bottom plane to be parallel to the axis of the main shaft, enabling the reading of the pointer of the dial indicator to be within 0.05mm, repeating the steps, and clamping the cast iron nut blank to ensure that the parallelism between the axis of the screw hole and the bottom plane is kept to be 0.01-0.05mm and the distance size is 4-5mm.
5. The processing technology of the cast iron nut as claimed in claim 1, wherein in the step S3, the clamping length of the cast iron nut blank clamped on the four-jaw single-action chuck is 25-30 mm.
6. The processing technology of the cast iron nut as claimed in claim 1, wherein in the step S3, an integral internal thread turning tool is selected, the internal thread is turned to 20-20.5mm in large diameter by using a straight flute tool, and then the tooth surface is turned by using the integral internal thread turning tool.
7. The processing technology of the cast iron nut according to claim 1, wherein in the step S4, the cast iron nut blank is screwed on the lead screw, the lead screw is clamped between two top points, a measuring head of the dial indicator contacts with the end surface of the cast iron nut blank, the nut is pushed axially left and right, and the swing value of a pointer of the dial indicator is not more than 0.1mm, namely the nut is qualified.
8. The processing technology of the cast iron nut as claimed in claim 1, wherein in the step S4, the cast iron nut blank is clamped between two centers, the magnetic force gauge stand is fixed on a saddle of a lathe, a measuring head of the dial indicator is in contact with a bottom plane, the horizontal position of the bottom plane is firstly aligned, then the saddle of the lathe is moved for measurement, and the swing value of the pointer of the dial indicator is not more than 0.08mm, so that the cast iron nut blank is qualified.
9. The processing technology of the cast iron nut as claimed in claim 1, wherein in step S6, the cast iron nut semi-finished product after being discharged is clamped by a three-jaw chuck to freely rotate, and forced air cooling is performed for 4-6 min.
10. The processing technology of the cast iron nut as claimed in claim 1, wherein in step S8, the semi-finished cast iron nut after tapping is clamped by a three-jaw chuck to rotate, and forced air cooling is performed for 3-4 min.
CN202211116376.XA 2022-09-14 2022-09-14 Processing technology of cast iron nut Pending CN115341075A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103659193A (en) * 2013-12-13 2014-03-26 重庆布莱迪仪器仪表有限公司 Machining process of balance cage type regulating valve locking nut
CN105886716A (en) * 2015-01-08 2016-08-24 标新科技（北京）有限公司 Secondary normalizing technique for liquefied petroleum gas cylinders
CN110900118A (en) * 2019-10-28 2020-03-24 瑞安市振安车辆配件有限公司 Nut machining process

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103659193A (en) * 2013-12-13 2014-03-26 重庆布莱迪仪器仪表有限公司 Machining process of balance cage type regulating valve locking nut
CN105886716A (en) * 2015-01-08 2016-08-24 标新科技（北京）有限公司 Secondary normalizing technique for liquefied petroleum gas cylinders
CN110900118A (en) * 2019-10-28 2020-03-24 瑞安市振安车辆配件有限公司 Nut machining process

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杨钟胜: "车床异形螺母的加工", 机械工艺师, no. 11, pages 17 - 18 *

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