Machining method for machining pin bush by adopting 100Cr6 bearing steel

Abstract

The invention relates to the field of pin bush production, in particular to a machining method for machining a pin bush through 100Cr6 bearing steel, and the machining method comprises the following steps: step 1, material modification; the metallographic structure, the grain size, the strength and the size of the raw materials are modified to meet the requirements of cold extrusion forming through material modification; 2, forming a main body; forming the pin bush through a cold heading process; step 3, appearance selection; and 4, the pin bushes selected in the step 3 are packaged and put in storage. The bearing steel is subjected to heat treatment in advance, the hardness of the bearing steel is reduced, the bearing steel can be suitable for cold heading production, and therefore the purposes can be achieved, and the problems that traditional turning machining is low in efficiency and poor in precision are solved.

Description

Technical Field

[0001] The invention relates to the field of pin sleeve production, in particular to a processing method for processing a pin sleeve by using 100Cr6 bearing steel. Background Art

[0002] 100Cr6 is a high-carbon chromium bearing steel. Due to its good processing properties, it can obtain a relatively stable and uniform structure and high and stable hardness.

[0003] It has excellent wear resistance and contact fatigue resistance, as well as suitable elasticity and toughness. It is mainly used in the manufacture of rolling bearings such as balls, rollers and pin bushings in conventional production.

[0004] However, because the hardness of conventional 100Cr6 bearing steel in hot-rolled state is above 150HRB, turning is often used when 100Cr6 bearing steel is used for pin sleeve production. Although traditional turning can realize the processing and production of pin sleeves, the processing efficiency is low and the production cost is high.

[0005] The existing patent 200810154957.6 - Processing method of deep hole pin sleeve parts does not clearly disclose the technical content for solving the above technical problems.

[0006] Therefore, in order to improve or solve at least one of the above problems, it is necessary to optimize the design of the existing pin sleeve processing method. Summary of the invention

[0007] The purpose of the present invention is to provide a processing method for manufacturing a pin sleeve using 100Cr6 bearing steel.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A processing method for processing a pin sleeve using 100Cr6 bearing steel, the processing method comprising the following steps:

[0010] Step 1: Material modification: Through material modification, the metallographic structure, grain size, strength and size of the raw materials are modified to meet the requirements of cold extrusion molding;

[0011] Step 2: Main body forming: Pin sleeve forming is achieved through cold heading process;

[0012] Step 3: Appearance selection;

[0013] Step 4: Pack the pin sleeves selected in step 3 and put them into storage.

[0014] In step 2, it is required to use a cold heading die to produce the pin sleeve.

[0015] The mold material of the cold heading mold is made of gradient tungsten steel SG50.

[0016] The cold heading process in step 2 comprises the following steps:

[0017] Step 1): initial upsetting: the original blank is subjected to multiple upsetting presses to form a preliminary processed blank;

[0018] Step 2): Preforming: further preforming the pre-processed blank after initial upsetting to make it closer to the final shape to form a preformed blank;

[0019] Step 3): Fine upsetting: Fine upsetting the preformed blank to form the required pin sleeve structure.

[0020] In the step 1), during the initial upsetting, it is required to form a preliminary processed blank through four upsettings; during each upsetting, a cold upsetting die is used to perform cold upsetting on the raw material.

[0021] After step 2 is completed, the oil removal operation is performed first and then step 3 is performed.

[0022] In the step 1, it is required to reduce the hardness of the raw material by spheroidizing annealing.

[0023] The raw material is subjected to at least two spheroidizing annealing processes to reduce the hardness of the raw material.

[0024] The material modification comprises the following steps: pickling, spheroidizing annealing, drawing and pickling phosphorus saponification.

[0025] The material modification comprises the following steps:

[0026] S1: first pickling;

[0027] S2: first spheroidizing annealing;

[0028] S3: second pickling;

[0029] S4: first pulling;

[0030] S5: second spheroidizing annealing;

[0031] S6: acid washing phosphorus saponification;

[0032] S7: Second pulling.

[0033] The advantages of the present invention are:

[0034] The invention mainly discloses a processing method for processing a pin sleeve by adopting 100Cr6 bearing steel.

[0035] The essence is to disclose a processing method of how to use 100Cr6 bearing steel through cold heading process to make pin sleeves.

[0036] The present invention heat treats the bearing steel in advance to reduce its hardness so that it can be suitable for cold heading production, thereby achieving the above purpose and avoiding the problems of low efficiency and poor precision of traditional turning processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0038] Figure 1 It is a process diagram of the pin sleeve pressing process in the present invention. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0040] In addition, 100Cr6 bearing steel is also called GCr15 bearing steel here.

[0041] GCr15 and 100Cr6 are the same material, both of which refer to high carbon chromium bearing steel. In different countries and standards, this material may have different numbers and names. In China, this material is usually called GCr15, while in international standards (such as ISO), it may be called 100Cr6. The chemical composition and performance characteristics of the two are basically the same, but the naming method is different.

[0042] A processing method for processing a pin sleeve using 100Cr6 bearing steel, the processing method comprising the following steps:

[0043] Step 1: Material modification: The metallographic structure, grain size, strength and size of the raw materials are modified to meet the requirements of cold extrusion molding through material modification; the main purpose is to reduce the hardness of the raw materials through material modification;

[0044] Step 2: Main body forming: Pin sleeve forming is achieved through cold heading process;

[0045] Step 3: Appearance selection;

[0046] Step 4: Pack the pin sleeves selected in step 3 and put them into storage.

[0047] The invention mainly discloses a processing method for processing a pin sleeve by adopting 100Cr6 bearing steel.

[0048] The essence is to disclose a processing method of how to use 100Cr6 bearing steel through cold heading process to make pin sleeves.

[0049] The present invention heat treats the bearing steel in advance to reduce its hardness so that it can be suitable for cold heading production, thereby achieving the above purpose and avoiding the problems of low efficiency and poor precision of traditional turning processing.

[0050] The processing method disclosed in the present invention mainly includes the steps of material modification, main body molding, appearance selection and packaging and warehousing.

[0051] Step 1: Material modification;

[0052] Purpose: To ensure that the metallographic structure, grain size, strength and size of the original material are modified to meet the requirements of cold extrusion of the pin sleeve.

[0053] That is, through material modification, the metallographic structure, grain size, strength and size of the raw materials are modified to be suitable for cold extrusion molding requirements, so as to facilitate subsequent processing.

[0054] Operation: usually includes pickling, spheroidizing annealing and other steps;

[0055] Pickling is used to remove the oxide scale and impurities on the surface, while spheroidizing annealing is used to improve the microstructure of the steel and spheroidize the carbides therein, thereby reducing the hardness and improving the plasticity and toughness;

[0056] Step 2: Main body molding;

[0057] Purpose: To realize the forming of pin sleeve by cold heading process.

[0058] Operation: Cold heading is a metal forming process. For pin bushings, cold heading can form them into precise size and shape.

[0059] Step 3: Appearance selection;

[0060] Purpose: To check whether the pin sleeve has surface defects after forming, such as cracks, scratches, deformation, etc.

[0061] Operation: This step is usually completed by manual or automated visual inspection systems to ensure product quality;

[0062] Step 4: Packing and storage;

[0063] Purpose: To package the pin sleeves that have been selected as qualified by appearance to protect the products from damage and facilitate storage and transportation;

[0064] Operation: Qualified bushings will be cleaned, dried, packaged, and then stored in the warehouse waiting for shipment or further processing.

[0065] The present invention is based on the above-mentioned entire processing flow and is intended to ensure that the quality and performance of the pin sleeve meet specific application requirements.

[0066] At the same time, due to its excellent hardness and wear resistance, 100Cr6 bearing steel is very suitable for manufacturing parts such as pins and sleeves that need to withstand high loads and friction.

[0067] Through the above steps, the processing efficiency and quality of the pin sleeve can be ensured.

[0068] Furthermore, in step 2 described in the present invention, it is required to use a cold heading die to produce the pin sleeve; such a setting facilitates the production and processing of the pin sleeve, and the mold material of the cold heading die described in the present invention is made of gradient tungsten steel SG50; such a setting can ensure the service life of the cold heading die to a certain extent.

[0069] Further, the cold heading process in step 2 of the present invention comprises the following steps:

[0070] Step 1): initial upsetting: the original blank is subjected to multiple upsetting presses to form a preliminary processed blank;

[0071] Step 2): Preforming: further preforming the pre-processed blank after initial upsetting to make it closer to the final shape to form a preformed blank;

[0072] Step 3): Fine upsetting: Fine upsetting the preformed blank to form the required pin sleeve structure.

[0073] Based on the above cold heading process, the cold heading processing of the pin sleeve can be realized.

[0074] In the present invention, step 1): initial upsetting;

[0075] Purpose: To perform multiple upsetting on the original blank to form a pre-processed blank;

[0076] Operation: Initial upsetting is the first step of the cold upsetting process. A press is usually used to upset a round or square metal billet to make its size and shape closer to the requirements of the final product. This step may need to be performed multiple times to gradually increase the size of the billet.

[0077] Step 2): Pre-forming

[0078] Purpose: To further preform the pre-processed blank after initial upsetting to make it closer to the final shape and form a preformed blank.

[0079] Operation: Preforming is an intermediate step in the cold heading process, the purpose of which is to make the shape of the preliminary processed blank closer to the shape of the final product.

[0080] This step may include trimming, flattening or other shaping operations on the edges of the blank to ensure that the blank will be formed into the correct shape in the fine upsetting step.

[0081] Step 3): Purpose of fine upsetting: Fine upsetting the preformed blank to form the required pin sleeve structure.

[0082] Operation: Fine heading is the final step in the cold heading process, the purpose of which is to accurately form the preform blank into the shape and size of the final product.

[0083] This step requires precise control of the pressure and forming die to ensure the dimensional accuracy and surface quality of the pin bushing.

[0084] During the entire cold heading process, the metal blank is gradually formed at room temperature. Through the above steps, it can be ensured that the pin sleeve has good mechanical properties and appearance quality before being put into use.

[0085] Furthermore, in step 1) described in the present invention, it is required to form a pre-processed blank through four upsettings during the initial upsetting; a cold upsetting die is used to cold upset the raw material each time; based on this design, cold pressing of structures such as small holes on the pin sleeve can be achieved, reducing the problem of high difficulty and low yield rate in one step.

[0086] Specific process embodiment:

[0087] The cold heading process includes the following steps:

[0088] S0: cutting to obtain the blank length of the required volume of the pin sleeve blank;

[0089] S1: shaping and chamfering, shaping in the mold, flattening the end face, chamfering and outer diameter;

[0090] S2: Flip shaping, in-mold shaping, flattening of sheared end faces, chamfering;

[0091] S3: Head positioning, in-mold shaping, and extrusion of end face positioning holes;

[0092] S4: flip positioning reduction table, in-mold shaping, extrusion stretch hole positioning hole, reduction table, T-slot;

[0093] S5: Stretching: stretching the inner hole to the finished product depth;

[0094] S6: Finishing and shaping: Finishing and shaping in the mold, final upsetting of the taper angle of the hole bottom and the end chamfer to complete the blank shape of the product.

[0095] Furthermore, after step 2 described in the present invention is completed, degreasing operation is performed before step 3; after the pin sleeve is cold-forged, there may be lubricating oil or other contaminants on the surface of the pin sleeve, which need to be removed through the degreasing step to ensure the cleanliness of the pin sleeve and the quality of subsequent processing.

[0096] Furthermore, in step 1 of the present invention, it is required to reduce the hardness of the raw material by spheroidizing annealing; the carbides in the steel are spheroidized by heat treatment to improve the plasticity and toughness of the material; in the present invention, the raw material is subjected to at least two spheroidizing annealings to reduce the hardness of the raw material; the present invention can improve the organizational structure of the blank by two spheroidizing annealings: after the first spheroidizing annealing, the carbides in the material may not be completely spheroidized; the second spheroidizing annealing can further promote the spheroidization of the carbides, so that the carbides are more evenly distributed on the ferrite matrix, thereby reducing the hardness and improving the machinability; for cold heading deformation preparation: under the condition of a certain holding temperature, the spheroidizing effect is better with the extension of the holding time, but if the holding time is too long, the cementite particles will grow according to the Ostwald ripening mechanism, which is not conducive to cold heading deformation.

[0097] Therefore, the second spheroidizing annealing can optimize the spheroidizing effect to meet the requirements of the cold heading process.

[0098] In summary, the two spheroidizing annealings help ensure that the material has better processing performance and longer service life, while improving the plasticity and toughness of the material, providing a good material state for subsequent cold heading process and other processing steps.

[0099] Furthermore, the material modification in the present invention includes the following steps: pickling, spheroidizing annealing, drawing and pickling phospho-saponification; pickling in the present invention: pickling is an important step in the material modification process, and its purpose is to remove the oxide film and rust stains on the surface of the raw material.

[0100] This step usually involves immersing the material in a bath of 20-25% hydrochloric acid at room temperature for several minutes; the key control points of pickling include the concentration of hydrochloric acid, the pickling time, and the pickling temperature.

[0101] Spheroidizing annealing: Spheroidizing annealing, also known as spheroidizing annealing, is an annealing process performed to spheroidize the carbides in the steel.

[0102] The purpose of this step is to produce a spheroidized structure, that is, a structure of spherical or granular carbides evenly distributed in a ferrite matrix, in order to improve the plasticity of the steel and reduce the hardness.

[0103] After spheroidizing annealing, the spheroidized structure and decarburized layer need to be inspected to confirm the spheroidizing effect. The hardness must meet the process requirements.

[0104] Drawing: It is a pressure processing method in which the original blank undergoes plastic deformation under a certain tensile force, thereby reducing the cross-section and increasing the length.

[0105] The purpose of drawing is to provide raw materials of corresponding specifications for cold heading production.

[0106] Acid washing phosphate saponification: Acid washing phosphate saponification is another important step in the material modification process, which includes two sub-steps of phosphating and saponifying.

[0107] Phosphating is a treatment that uses chemical methods to form a phosphate film on the surface of the original blank. The film thickness is generally 10-15 microns. The purpose is to reduce the scratches on the tooling during wire drawing, cold heading or forming, and play a lubricating role. It also has a certain rust prevention effect. Saponification is a lubrication treatment method that uses sodium stearate or soap as a lubricant to make the phosphate in the phosphate layer react chemically to generate zinc stearate, the purpose of which is to provide lubrication.

[0108] Furthermore, the material modification in the present invention comprises the following steps:

[0109] S1: first pickling;

[0110] S2: first spheroidizing annealing;

[0111] S3: second pickling;

[0112] S4: first pulling;

[0113] S5: second spheroidizing annealing;

[0114] S6: acid washing phosphorus saponification;

[0115] S7: Second pulling.

[0116] Through the coordination of the above-mentioned processes, the raw material can be optimized to obtain a raw billet whose metallographic structure, grain size, strength and size are modified to meet the requirements of cold extrusion forming of the pin sleeve.

[0117] In the present invention

[0118] S1: First pickling:

[0119] Purpose: To remove scale, rust and other impurities from the surface of wire.

[0120] Method: Usually an acid solution, such as hydrochloric acid or sulfuric acid, is used by immersion or spraying.

[0121] S2: First spheroidizing annealing:

[0122] Purpose: To transform carbides in steel into spherical shapes to improve the plasticity and toughness of the material

[0123] Method: Heat the material to a certain temperature and keep it for a period of time, then cool it down slowly.

[0124] S3: Second pickling:

[0125] Purpose: To remove the oxide layer that may be formed after the first spheroidizing annealing.

[0126] Method: Similar to the first pickling, ensure the material surface is clean.

[0127] S4: First pull:

[0128] Purpose: To draw the material into the required size and shape in preparation for cold heading.

[0129] Method: Through a drawing machine and a die, tension is applied to the material so that it passes through the die aperture and is reduced.

[0130] S5: Second spheroidizing annealing:

[0131] Purpose: After the first drawing, spheroidizing annealing is performed again to maintain the plasticity and toughness of the material.

[0132] Method: Same as the first spheroidizing annealing.

[0133] S6: acid washing phosphorus saponification:

[0134] Purpose: To provide lubrication and anti-rust protection, and to provide good surface conditions for subsequent drawing and cold heading.

[0135] Method: First, pickling is performed to remove surface impurities, then phosphating is performed to form a phosphate film, and finally saponification is performed to increase lubricity.

[0136] S7: Second drawing: Purpose: To further accurately adjust the size and shape of the material to ensure that it meets the requirements of cold heading.

[0137] Method: Similar to the first drawing, but may use a finer die to achieve more precise dimensions.

[0138] The reasons why two spheroidizing annealings are used to reduce the hardness of the blank in the present invention mainly include the following points:

[0139] Improve the organizational structure: The first spheroidizing annealing can make the carbides (such as Fe3C) in the steel begin to spheroidize, but it may not be completely spheroidized, especially for steels with serious lamellar pearlite; the second spheroidizing annealing can further promote the spheroidization of carbides and make the carbides more evenly distributed on the ferrite matrix, thereby reducing the hardness and improving the machinability.

[0140] Improve spheroidizing quality: The first spheroidizing annealing may not be able to completely eliminate the network carbides.

[0141] Before the first spheroidizing annealing, normalizing treatment may be required to eliminate network carbides, and then a second spheroidizing annealing is performed to ensure the normal progress of spheroidizing annealing and improve the spheroidizing quality; Improve plasticity and toughness: Two spheroidizing annealings can not only reduce the hardness, but also improve the plasticity and toughness of the steel, which is very important for subsequent processing and use.

[0142] The distribution of spheroidal carbides can reduce deformation and cracking tendency during quenching and improve mechanical toughness.

[0143] In summary, the double spheroidizing annealing can reduce the hardness of the original billet by improving the distribution of carbides and controlling the cooling rate, while improving the plasticity and toughness of the material, laying a good foundation for subsequent processing and use.

[0144] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A method for processing a pin sleeve using 100Cr6 bearing steel, characterized in that: The processing method comprises the following steps: Step 1: Material modification: Through material modification, the metallographic structure, grain size, strength and size of the raw materials are modified to meet the requirements of cold extrusion molding; Step 2: Main body forming: Pin sleeve forming is achieved through cold heading process; Step 3: Appearance selection; Step 4: Pack the pin sleeves selected in step 3 and put them into storage.

2. The method for machining a pin sleeve using 100Cr6 bearing steel according to claim 1 is characterized in that: In step 2, it is required to use a cold heading die to produce the pin sleeve.

3. The method for machining a pin sleeve using 100Cr6 bearing steel according to claim 2 is characterized in that: The mold material of the cold heading mold is made of gradient tungsten steel SG50.

4. The method for machining a pin sleeve using 100Cr6 bearing steel according to claim 3 is characterized in that: The cold heading process in step 2 comprises the following steps: Step 1): initial upsetting: the original blank is subjected to multiple upsetting presses to form a preliminary processed blank; Step 2): Preforming: further preforming the pre-processed blank after initial upsetting to make it closer to the final shape to form a preformed blank; Step 3): Fine upsetting: Fine upsetting the preformed blank to form the required pin sleeve structure.

5. The method for machining a pin sleeve using 100Cr6 bearing steel according to claim 4 is characterized in that: In the step 1), during the initial upsetting, it is required to form a preliminary processed blank through four upsettings; during each upsetting, a cold upsetting die is used to perform cold upsetting on the raw material.

6. The method for machining a pin sleeve using 100Cr6 bearing steel according to claim 2 is characterized in that: After step 2 is completed, the oil removal operation is performed first and then step 3 is performed.

7. The method for machining a pin sleeve using 100Cr6 bearing steel according to claim 1 is characterized in that: In the step 1, it is required to reduce the hardness of the raw material by spheroidizing annealing.

8. The method for machining a pin sleeve using 100Cr6 bearing steel according to claim 7 is characterized in that: The raw material is subjected to at least two spheroidizing annealing processes to reduce the hardness of the raw material.

9. A method for machining a pin sleeve using 100Cr6 bearing steel according to any one of claims 1 to 7, characterized in that: The material modification comprises the following steps: pickling, spheroidizing annealing, drawing and pickling phosphorus saponification.

10. A method for machining a pin sleeve using 100Cr6 bearing steel according to claim 9, characterized in that: The material modification comprises the following steps: S1: first pickling; S2: first spheroidizing annealing; S3: second pickling; S4: first pulling; S5: second spheroidizing annealing; S6: acid washing phosphorus saponification; S7: Second pulling.

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