Axial displacement measurement type laser cladding piston rod and preparation process thereof

Abstract

The present application relates to the technical field of piston rod, and particularly relates to an axial displacement measurement type laser cladding piston rod. The method of conventional laser cladding fills a non-magnetic coating in an annular groove on the surface of a piston rod base, and the linear stroke of the piston rod calculated from the electromagnetic induction signal obtained by an electromagnetic induction element is poor in consistency with the actual linear stroke. In view of the above problem, the present application provides an axial displacement measurement type laser cladding piston rod, and the upper surface of the boss formed between the adjacent annular grooves on the outer wall of the base is free of metallurgical combination with the cladded metal, so that the detection precision is obviously improved, and the linear stroke of the piston rod calculated from the electromagnetic induction signal is better in consistency with the actual linear stroke.

Description

Technical Field

[0001] This invention belongs to the field of piston rod technology, specifically relating to an axial displacement measuring laser cladding piston rod and its manufacturing process. Background Technology

[0002] To detect the axial displacement of a hydraulic cylinder piston rod, relative or absolute stroke detection techniques are typically used to measure its linear stroke. Both techniques generally involve creating grooves on the surface of a magnetically conductive piston rod substrate, filling these grooves with a non-magnetic ceramic coating, and finally applying a protective coating to the outer surface of the piston rod. When the piston rod reciprocates, an electromagnetic induction element performs a magnetic scan. As the element passes through the groove, it generates the same or different electromagnetic induction signals depending on the shape and size of the groove's axial cross-section. By statistically analyzing, calculating, and converting the acquired electromagnetic induction signals, the relative or absolute displacement of the piston rod can be obtained.

[0003] The solutions adopted by Chinese patents CN201193630Y, CN207634444U, CN209539707U, CN209180157U, CN112431820A, etc., all involve spraying non-magnetic ceramic material into the groove of the piston rod. The ceramic coating obtained by this method only forms a mechanical bond with the inner wall of the groove, and the bonding force is poor. The ceramic coating is very easy to fall off from the groove of the piston rod, resulting in a poor service life.

[0004] Chinese invention patent CN103671350A discloses a piston rod for a hydraulic gate hoist cylinder with an electromagnetic stroke measurement method using laser cladding of alloy powder. This method fills the piston rod grooves with alloy powder using laser cladding. While this improves the adhesion between the non-magnetic coating and the groove wall to some extent, the laser cladding method forms a metallurgical bonding layer between the cladding metal and the piston rod substrate. This results in a poor match between the linear stroke of the piston rod calculated from the electromagnetic induction signal acquired by the electromagnetic induction element and the actual stroke. The accuracy of the piston rod axial linear displacement measurement needs further improvement. Summary of the Invention

[0005] A problem with existing technologies is that conventional laser cladding methods fill the annular grooves on the piston rod substrate surface with a non-magnetic coating, resulting in a poor correlation between the linear stroke of the piston rod calculated from the electromagnetic induction signal obtained by the electromagnetic induction element and the actual stroke. To address this problem, this invention provides an axial displacement measuring laser cladding piston rod, comprising a piston rod substrate,

[0006] The piston rod base surface is provided with several annular grooves parallel to its axial direction. The axial cross-sections of the annular grooves are all the same shape, which are all rectangular cross-sections. The radial width of the rectangular cross-sections is equal. The groove opening surface of the annular groove is flush with the surface of the piston rod base. The groove depth of the annular groove is 0.3-0.35mm.

[0007] The annular groove is provided with a cladding metal layer, which completely fills the annular groove, and the outer surface of the cladding metal layer is flush with the outer surface of the piston rod substrate.

[0008] The cladding metal is non-magnetic;

[0009] The piston rod substrate is magnetically conductive;

[0010] A protective coating is provided circumferentially on the outer surface of the piston rod substrate, and the protective coating is 0.3-0.35 mm higher than the substrate surface;

[0011] The bosses formed between adjacent annular grooves in the axial direction do not have their upper surfaces metallurgically bonded to the cladding metal.

[0012] Preferably, the bottom of the rectangular cross-section is symmetrically chamfered, and the chamfer is greater than 0°.

[0013] Preferably, the chamfer is a chamfer of any size between two endpoints within the range of 27.5-45°.

[0014] Preferably, the cladding metal comprises austenitic stainless steel or a nickel-based alloy.

[0015] Preferably, the piston rod base is made of carbon steel or alloy steel.

[0016] Preferably, the carbon steel is 45. # steel.

[0017] Preferably, the alloy steel includes any one of Q345D, Q460D, and 27SiMn alloy steel.

[0018] Preferably, the material used for the protective coating includes any one of the following iron-based alloy powders: Hagenas Rockit 401, Yunding Optoelectronics F1055, and Tianjin Zhujin JG11.

[0019] Preferably, the axial lengths of the rectangular sections are equal, the spacing between adjacent rectangular sections is equal, the axial length is 2mm-10mm, and the spacing is 2mm-10mm.

[0020] Preferably, the axial lengths of the rectangular cross sections are not equal, the spacing between adjacent rectangular cross sections is different, the axial length of a single coding interval is 1.5mm-3mm, and the spacing ranges from 1.5mm-30mm.

[0021] Preferably, the manufacturing process of the stroke-measuring laser cladding piston rod includes the following steps:

[0022] (1) Several annular grooves are arranged parallel to each other along the axial direction on the surface of the piston rod base. The axial cross-sections of the annular grooves are all rectangular cross-sections with equal radial widths. The groove openings of the annular grooves are flush with the surface of the piston rod base. The groove depth of the annular grooves is 0.45-0.5 mm.

[0023] (2) Metal is uniformly clad along the outer wall of the piston rod substrate to obtain a clad metal layer that is 0.3-0.35 mm higher than the outer wall of the piston rod. Then, the clad metal layer is uniformly ground along the outer wall of the piston rod until the remaining 0.3-0.35 mm is polished.

[0024] (4) Next, a protective coating is uniformly fused onto the outer wall of the piston rod substrate in the axial direction to obtain a protective coating with a thickness of 0.5-0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating is reduced to 0.3-0.35 mm.

[0025] The present invention has the following beneficial effects:

[0026] The piston rod obtained by the process of this invention forms a metallurgical bond between the upper surface of the protrusion formed between the axial direction of the adjacent annular grooves on the outer wall of the base metal and the cladding metal, which significantly improves the detection accuracy and the linear stroke of the piston rod calculated by the electromagnetic induction signal is more consistent with the actual value. Attached Figure Description

[0027] Figure 1 : A partial axial cross-sectional view of a stroke-measuring laser cladding piston rod according to the present invention.

[0028] Figure 2 : A schematic diagram of a partial axial cross-section of a laser cladding piston rod for measuring stroke before metal cladding according to the present invention.

[0029] In the figure, 1. Protective coating, 2. Clad metal, 3. Piston rod substrate, 4. Chamfer, 5. Annular groove, 6. Electromagnetic induction element. Detailed Implementation

[0030] The present invention will be described in detail below with reference to embodiments. However, it should be understood that the following embodiments are merely illustrative examples of implementation of the present invention and are not intended to limit the scope of the present invention.

[0031] like Figure 1-2 As shown, an axial displacement measuring laser cladding piston rod of the present invention includes a piston rod base 3.

[0032] The piston rod base 3 has several annular grooves 5 arranged parallel to its axial direction on its surface. The axial cross-sections of the annular grooves 5 are all rectangular, and the radial widths of the rectangular cross-sections are equal. The groove openings of the annular grooves 5 are flush with the surface of the piston rod base 3, and the groove depth of the annular grooves 5 is 0.3-0.35 mm.

[0033] The bottom of the rectangular cross section is symmetrically provided with chamfer 4, and the chamfer 4 is greater than 0°;

[0034] The annular groove 5 is provided with a cladding metal layer 2, which completely fills the annular groove 5, and the outer surface of the cladding metal layer 2 is flush with the outer surface of the piston rod base 3.

[0035] The cladding metal 2 is non-magnetic;

[0036] The piston rod base 3 is magnetically conductive;

[0037] A protective coating 1 is provided circumferentially on the outer surface of the piston rod substrate 3, and the protective coating 1 is 0.3-0.35 mm higher than the substrate surface;

[0038] The boss formed between adjacent annular grooves 5 in the axial direction has no metallurgical bond between its upper surface and the cladding metal 2.

[0039] To improve detection accuracy and achieve accurate measurement of piston rod axial displacement, the chamfer 4 is a chamfer 4 of any size between two endpoints in the range of 27.5-45°, specifically a 45° chamfer 4.

[0040] The cladding metal 2 includes austenitic stainless steel or nickel-based alloy.

[0041] The piston rod base 3 is made of carbon steel or alloy steel.

[0042] The carbon steel is 45. # steel.

[0043] The alloy steel includes any one of Q345D, Q460D, and 27SiMn.

[0044] The material used in the protective coating 1 includes any one of the following iron-based alloy powders: Hagenas Rockit 401, Yunding Optoelectronics F1055, and Tianjin Zhujin JG11.

[0045] To achieve accurate measurement of the axial relative displacement of the piston rod, the axial lengths of the rectangular sections are equal, and the spacing between adjacent rectangular sections is equal.

[0046] In order to achieve accurate measurement of the absolute axial displacement of the piston rod, the axial lengths of the rectangular sections are not equal, and the spacing between adjacent rectangular sections is different.

[0047] The aforementioned stroke-measuring laser cladding piston rod is manufactured using the following steps:

[0048] (1) Several annular grooves 5 are arranged parallel to each other along the axial direction on the surface of the piston rod base 3. The axial cross-sections of the annular grooves 5 are all rectangular cross-sections with the same radial width. The bottom of the rectangular cross-sections is symmetrically provided with chamfers 4, which are greater than 0°. The groove opening surface of the annular grooves 5 is flush with the surface of the piston rod base 3. The groove depth of the annular grooves 5 is 0.45-0.5 mm.

[0049] (2) Metal 2 is uniformly clad along the outer wall of the piston rod base 3 to obtain a layer of clad metal 2 that is 0.3-0.35 mm higher than the outer wall of the piston rod. Then, the piston rod is uniformly ground along the outer wall of the piston rod until the groove depth of the annular groove 5 is 0.3-0.35 mm. This ensures that the clad metal 2 layer is only present in the annular groove 5 and all others are removed. This prevents the upper surface of the protrusion formed between adjacent annular grooves 5 from having a metallurgical bonding layer with the clad metal 2 that could interfere with the electromagnetic induction signal.

[0050] (4) Next, a protective coating 1 is uniformly fused onto the outer wall of the piston rod substrate 3 in the axial direction to obtain a protective coating 1 with a thickness of 0.5-0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating 1 is reduced to 0.3-0.35 mm. Since the material of the protective coating 1 is an iron-based alloy, it will inevitably interfere with the electromagnetic signal generated on the surface of the piston rod substrate 3. Reducing the thickness of the protective coating 1 helps to improve the detection accuracy and the degree of consistency between the displacement test data of the electromagnetic induction element 6 and the actual axial displacement of the piston rod. Example

[0051] A stroke-measuring laser cladding piston rod, the fabrication process of which is as follows:

[0052] (1) 100 annular grooves 5 are arranged parallel to the piston rod base 3 along its axial direction. The axial cross-sections of the annular grooves 5 are all rectangular cross-sections with equal radial widths. The bottom of the rectangular cross-sections is not symmetrically provided with chamfers 4. The groove opening surface of the annular grooves 5 is flush with the surface of the piston rod base 3. The groove depth of the annular grooves 5 is 0.45 mm. The axial lengths of the rectangular cross-sections are equal, and the spacing between adjacent rectangular cross-sections is equal. The axial length is 5 mm and the spacing is 5 mm.

[0053] (2) Metal 2 is uniformly clad along the outer wall of the piston rod base 3 to obtain a layer of clad metal 2 that is 0.35 mm higher than the outer wall of the piston rod. Then, it is uniformly ground along the outer wall of the piston rod until the groove depth of the annular groove 5 is 0.35 mm, so that the clad metal 2 layer is only left in the annular groove 5 and all others are removed.

[0054] (4) Next, a protective coating 1 is uniformly fused onto the outer wall of the piston rod substrate 3 in the axial direction to obtain a protective coating 1 with a thickness of 0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating 1 is reduced to 0.35 mm. Since the material of the protective coating 1 is an iron-based alloy, it will inevitably interfere with the electromagnetic signal generated on the surface of the piston rod substrate 3. Reducing the thickness of the protective coating 1 helps to improve the detection accuracy and improve the consistency between the displacement test data of the electromagnetic induction element 6 and the actual axial displacement of the piston rod.

[0055] The cladding metal 2 is austenitic stainless steel 316L.

[0056] The piston rod base 3 is 45 # steel.

[0057] The alloy steel is Q345D alloy steel.

[0058] The protective coating 1 is made of Hagenas Rockit 401 iron-based alloy powder.

[0059] The axial displacement of the piston rod obtained in Example 1 was tested using an electromagnetic induction element 6 (ALLEGRO ATS667LSG). When the actual axial displacement of the piston rod was 1000 mm, the displacement data obtained by the electromagnetic induction element 6 was 999.3 mm, and the measurement error was 0.7 mm. Example

[0060] A stroke-measuring laser cladding piston rod, the fabrication process of which is as follows:

[0061] (1) 100 annular grooves 5 are arranged parallel to the piston rod base 3 along its axial direction. The axial cross-sections of the annular grooves 5 are all rectangular cross-sections with equal radial widths. The bottom of the rectangular cross-sections is symmetrically provided with chamfers 4, which are 27.5°. The groove opening surface of the annular grooves 5 is flush with the surface of the piston rod base 3. The groove depth of the annular grooves 5 is 0.45 mm. The axial lengths of the rectangular cross-sections are equal, and the spacing between adjacent rectangular cross-sections is equal. The axial length is 5 mm and the spacing is 5 mm.

[0062] (2) Metal 2 is uniformly clad along the outer wall of the piston rod base 3 to obtain a layer of clad metal 2 that is 0.35 mm higher than the outer wall of the piston rod. Then, it is uniformly ground along the outer wall of the piston rod until the groove depth of the annular groove 5 is 0.35 mm, so that the clad metal 2 layer is only left in the annular groove 5 and all others are removed.

[0063] (4) Next, a protective coating 1 is uniformly fused onto the outer wall of the piston rod substrate 3 in the axial direction to obtain a protective coating 1 with a thickness of 0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating 1 is reduced to 0.35 mm. Since the material of the protective coating 1 is an iron-based alloy, it will inevitably interfere with the electromagnetic signal generated on the surface of the piston rod substrate 3. Reducing the thickness of the protective coating 1 helps to improve the detection accuracy and improve the consistency between the displacement test data of the electromagnetic induction element 6 and the actual axial displacement of the piston rod.

[0064] The cladding metal 2 is austenitic stainless steel 316L.

[0065] The piston rod base 3 is 45 # steel.

[0066] The alloy steel is Q345D alloy steel.

[0067] The protective coating 1 is made of Hagenas Rockit 401 iron-based alloy powder.

[0068] The axial displacement of the piston rod obtained in Example 2 was tested using an electromagnetic induction element 6 (ALLEGRO ATS667LSG). When the actual axial displacement of the piston rod was 1000 mm, the displacement data obtained by the electromagnetic induction element 6 was 999.7 mm, and the measurement error was 0.3 mm. Example

[0069] A stroke-measuring laser cladding piston rod, the fabrication process of which is as follows:

[0070] (1) 100 annular grooves 5 are arranged parallel to the piston rod base 3 along its axial direction. The axial cross-sections of the annular grooves 5 are all rectangular cross-sections with equal radial widths. The bottom of the rectangular cross-sections is symmetrically provided with chamfers 4, which are 45°. The groove opening surface of the annular grooves 5 is flush with the surface of the piston rod base 3. The groove depth of the annular grooves 5 is 0.45 mm. The axial lengths of the rectangular cross-sections are equal, and the spacing between adjacent rectangular cross-sections is equal. The axial length is 5 mm and the spacing is 5 mm.

[0071] (2) Metal 2 is uniformly clad along the outer wall of the piston rod base 3 to obtain a layer of clad metal 2 that is 0.35 mm higher than the outer wall of the piston rod. Then, it is uniformly ground along the outer wall of the piston rod until the groove depth of the annular groove 5 is 0.35 mm, so that the clad metal 2 layer is only left in the annular groove 5 and all others are removed.

[0072] (4) Next, a protective coating 1 is uniformly fused onto the outer wall of the piston rod substrate 3 in the axial direction to obtain a protective coating 1 with a thickness of 0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating 1 is reduced to 0.35 mm. Since the material of the protective coating 1 is an iron-based alloy, it will inevitably interfere with the electromagnetic signal generated on the surface of the piston rod substrate 3. Reducing the thickness of the protective coating 1 helps to improve the detection accuracy and improve the consistency between the displacement test data of the electromagnetic induction element 6 and the actual axial displacement of the piston rod.

[0073] The cladding metal 2 is austenitic stainless steel 316L.

[0074] The piston rod base 3 is 45 # steel.

[0075] The alloy steel is Q345D alloy steel.

[0076] The protective coating 1 is made of Hagenas Rockit 401 iron-based alloy powder.

[0077] The axial displacement of the piston rod obtained in Example 3 was tested using an electromagnetic induction element 6 (ALLEGRO ATS667LSG). When the actual axial displacement of the piston rod was 1000 mm, the displacement data obtained by the electromagnetic induction element 6 was 999.9 mm, and the measurement error was 0.1 mm.

[0078] Comparative Example 1

[0079] A stroke-measuring laser cladding piston rod, the fabrication process of which is as follows:

[0080] (1) 100 annular grooves 5 are arranged parallel to the piston rod base 3 along its axial direction. The axial cross-sections of the annular grooves 5 are all rectangular cross-sections with equal radial widths. The bottom of the rectangular cross-sections is symmetrically provided with chamfers 4, which are 45°. The groove opening surface of the annular grooves 5 is flush with the surface of the piston rod base 3. The groove depth of the annular grooves 5 is 0.45 mm. The axial lengths of the rectangular cross-sections are equal, and the spacing between adjacent rectangular cross-sections is equal. The axial length is 5 mm and the spacing is 5 mm.

[0081] (2) Metal 2 is uniformly clad along the outer wall of the piston rod base 3 to obtain a layer of clad metal 2 that is 0.35 mm higher than the outer wall of the piston rod. Then, it is uniformly ground along the outer wall of the piston rod until the surface of the boss formed between the adjacent annular grooves on the outer wall of the piston rod is left with 0.2 mm of clad metal 2.

[0082] (4) Next, a protective coating 1 is uniformly fused onto the outer wall of the piston rod substrate 3 in the axial direction to obtain a protective coating 1 with a thickness of 0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating 1 is reduced to 0.35 mm. Since the material of the protective coating 1 is an iron-based alloy, it will inevitably interfere with the electromagnetic signal generated on the surface of the piston rod substrate 3. Reducing the thickness of the protective coating 1 helps to improve the detection accuracy and improve the consistency between the displacement test data of the electromagnetic induction element 6 and the actual axial displacement of the piston rod.

[0083] The cladding metal 2 is austenitic stainless steel 316L.

[0084] The piston rod base 3 is 45 # steel.

[0085] The alloy steel is Q345D alloy steel.

[0086] The protective coating 1 is made of Hagenas Rockit 401 iron-based alloy powder.

[0087] The axial displacement of the piston rod obtained in Comparative Example 1 was tested using an electromagnetic induction element 6 (ALLEGRO ATS667LSG). When the actual axial displacement of the piston rod was 1000 mm, the displacement data obtained by the electromagnetic induction element 6 was 999.2 mm, and the measurement error was 0.8 mm.

[0088] Comparative Example 2

[0089] A stroke-measuring laser cladding piston rod, the fabrication process of which is as follows:

[0090] (1) 100 annular grooves 5 are arranged parallel to the piston rod base 3 along its axial direction. The axial cross-sections of the annular grooves 5 are all rectangular cross-sections with equal radial widths. The bottom of the rectangular cross-sections is symmetrically provided with chamfers 4, which are 45°. The groove opening surface of the annular grooves 5 is flush with the surface of the piston rod base 3. The groove depth of the annular grooves 5 is 0.45 mm. The axial lengths of the rectangular cross-sections are equal, and the spacing between adjacent rectangular cross-sections is equal. The axial length is 5 mm and the spacing is 5 mm.

[0091] (2) Metal 2 is uniformly clad along the outer wall of the piston rod base 3 to obtain a layer of clad metal 2 that is 0.35 mm higher than the outer wall of the piston rod. Then, it is uniformly ground along the outer wall of the piston rod until the surface of the boss formed between the adjacent annular grooves on the outer wall of the piston rod is left with 0.1 mm of clad metal 2.

[0092] (4) Next, a protective coating 1 is uniformly fused onto the outer wall of the piston rod substrate 3 in the axial direction to obtain a protective coating 1 with a thickness of 0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating 1 is reduced to 0.35 mm. Since the material of the protective coating 1 is an iron-based alloy, it will inevitably interfere with the electromagnetic signal generated on the surface of the piston rod substrate 3. Reducing the thickness of the protective coating 1 helps to improve the detection accuracy and improve the consistency between the displacement test data of the electromagnetic induction element 6 and the actual axial displacement of the piston rod.

[0093] The cladding metal 2 is austenitic stainless steel 316L.

[0094] The piston rod base 3 is 45 # steel.

[0095] The alloy steel is Q345D alloy steel.

[0096] The protective coating 1 is made of Hagenas Rockit 401 iron-based alloy powder.

[0097] The axial displacement of the piston rod obtained in Comparative Example 2 was tested using an electromagnetic induction element 6 (ALLEGRO ATS667LSG). When the actual axial displacement of the piston rod was 1000 mm, the displacement data obtained by the electromagnetic induction element 6 was 999.5 mm, and the measurement error was 0.5 mm.

[0098] Comparative Example 3

[0099] A stroke-measuring laser cladding piston rod, the fabrication process of which is as follows:

[0100] (1) 100 annular grooves 5 are arranged parallel to the piston rod base 3 along its axial direction. The axial cross-sections of the annular grooves 5 are all rectangular cross-sections with equal radial widths. The bottom of the rectangular cross-sections is symmetrically provided with chamfers 4, which are 45°. The groove opening surface of the annular grooves 5 is flush with the surface of the piston rod base 3. The groove depth of the annular grooves 5 is 0.45 mm. The axial lengths of the rectangular cross-sections are equal, and the spacing between adjacent rectangular cross-sections is equal. The axial length is 5 mm and the spacing is 5 mm.

[0101] (2) Metal 2 is uniformly clad along the outer wall of the piston rod base 3 to obtain a layer of clad metal 2 that is 0.35 mm higher than the outer wall of the piston rod. Then, it is uniformly ground along the outer wall of the piston rod until all the clad metal 2 layer on the surface of the boss formed between the adjacent annular grooves on the outer wall of the piston rod is ground off.

[0102] (4) Next, a protective coating 1 is uniformly fused onto the outer wall of the piston rod substrate 3 in the axial direction to obtain a protective coating 1 with a thickness of 0.6 mm. Then, the outer wall of the piston rod is uniformly ground radially until the thickness of the protective coating 1 is reduced to 0.35 mm. Since the material of the protective coating 1 is an iron-based alloy, it will inevitably interfere with the electromagnetic signal generated on the surface of the piston rod substrate 3. Reducing the thickness of the protective coating 1 helps to improve the detection accuracy and improve the consistency between the displacement test data of the electromagnetic induction element 6 and the actual axial displacement of the piston rod.

[0103] The cladding metal 2 is austenitic stainless steel 316L.

[0104] The piston rod base 3 is 45 # steel.

[0105] The alloy steel is Q345D alloy steel.

[0106] The protective coating 1 is made of Hagenas Rockit 401 iron-based alloy powder.

[0107] The axial displacement of the piston rod obtained in Comparative Example 3 was tested using an electromagnetic induction element 6 (ALLEGRO ATS667LSG). When the actual axial displacement of the piston rod was 1000 mm, the displacement data obtained by the electromagnetic induction element 6 was 999.7 mm, and the measurement error was 0.3 mm.

[0108] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A laser cladding piston rod for measuring axial displacement, characterized in that, Includes piston rod base (3). The piston rod base (3) has several annular grooves (5) arranged parallel to its axial direction on its surface. The axial cross-sections of the annular grooves (5) are all rectangular cross-sections with equal radial widths. The groove openings of the annular grooves (5) are flush with the surface of the piston rod base (3). The groove depth of the annular grooves (5) is 0.3-0.35 mm. The annular groove (5) is provided with a cladding metal (2) layer, which completely fills the annular groove (5), and the outer surface of the cladding metal (2) layer is flush with the outer surface of the piston rod base (3). The cladding metal (2) is non-magnetic; The piston rod substrate (3) is magnetically conductive; The outer surface of the piston rod substrate (3) is provided with a protective coating (1) in the circumferential direction, and the protective coating (1) is 0.3-0.35 mm higher than the surface of the substrate; The upper surface of the protrusion formed between adjacent annular grooves (5) in the axial direction does not form a metallurgical bond with the cladding metal (2); The bottom of the rectangular cross section is symmetrically provided with a chamfer (4), and the chamfer (4) is greater than 0°.

2. The laser cladding piston rod for axial displacement measurement according to claim 1, characterized in that, The chamfer (4) is a chamfer (4) of any size between two endpoint values ​​in the range of 27.5-45°.

3. The laser cladding piston rod for axial displacement measurement according to claim 1, characterized in that, The piston rod base (3) is made of carbon steel or alloy steel.

4. The laser cladding piston rod for axial displacement measurement according to claim 3, characterized in that, The carbon steel is 45. # steel.

5. The laser cladding piston rod for axial displacement measurement according to claim 3, characterized in that, The alloy steel includes any one of Q345D, Q460D, and 27SiMn.

6. The laser cladding piston rod for axial displacement measurement according to claim 1, characterized in that, The protective coating (1) is made of any one of the following iron-based alloy powders: Hagenas Rockit 401, Yunding Optoelectronics F1055, and Tianjin Zhujin JG11.

7. The laser cladding piston rod for axial displacement measurement according to claim 1, characterized in that, The rectangular sections have equal axial lengths and equal spacing between adjacent rectangular sections.

8. The laser cladding piston rod for axial displacement measurement according to claim 1, characterized in that, The axial lengths of the rectangular sections are not equal, and the spacing between adjacent rectangular sections is different.

9. The laser cladding piston rod for axial displacement measurement according to claim 1, characterized in that, The preparation process includes the following steps: (1) Several annular grooves (5) are arranged parallel to each other along the axial direction on the surface of the piston rod base (3). The axial cross-sections of the annular grooves (5) are all rectangular cross-sections with equal radial widths. The groove opening surface of the annular grooves (5) is flush with the surface of the piston rod base (3). The groove depth of the annular grooves (5) is 0.45-0.5mm. (2) Metal (2) is uniformly clad along the outer wall of the piston rod substrate (3) to obtain a clad metal (2) layer that is 0.3-0.35 mm higher than the outer wall of the piston rod. Then, the clad metal (2) layer is uniformly ground along the outer wall of the piston rod until the remaining 0.3-0.35 mm is ground. (4) Next, a protective coating (1) is uniformly fused onto the outer wall of the piston rod substrate (3) in the axial direction. The thickness of the protective coating (1) is 0.5-0.6 mm. Then, the outer wall of the piston rod is uniformly ground in the radial direction until the thickness of the protective coating (1) is 0.3-0.35 mm.

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