A fixture for electrochemically assisted erosion of a wire

Abstract

The utility model relates to a fixture for metal wire electrochemistry auxiliary erosion belongs to metallographic experimental technical field. Technical scheme is: the base (1) is equipped with a plurality of through -hole, the upper part of through -hole is larger round hole, the middle part is taper hole, the lower part is smaller round hole, metal clamping block (3) is fixed in the round hole of base (1) lower part, fastening peg (2) is screwed on the larger round hole and taper hole of base (1) upper part and middle part, the center of fastening peg (2) and metal clamping block (3) is equipped with the center hole matched with wire sample (4) respectively, the upper part of fastening peg (2) is peg cap (5), is equipped with outer thread (6) in the middle, is taper below. When experimenting, metal clamping block (3) and wire sample (4) are used as primary cell, and nitric acid alcohol is used for erosion. The utility model has the beneficial effects that: the fast clamping of wire sample can be realized, and multiple samples can be accommodated, and the metal wire metallographic sample preparation efficiency is greatly improved.

Description

Technical Field

[0001] This utility model relates to a clamp for electrochemical assisted etching of metal wires, belonging to the field of metallographic etching experimental technology in the metallurgical industry. Background Technology

[0002] In the electrochemical-assisted etching process of metal wires, etching wires with special compositions is particularly difficult, especially for drawn samples. The etching process is even more complex under different working conditions such as heat treatment and deformation, making it more difficult to obtain clear microstructures. For example, high-manganese steel welding wire has relatively stable chemical properties, requiring long etching times using conventional methods, resulting in poor metallographic clarity and the formation of pitting corrosion pits under prolonged etching, affecting microstructure observation. Higher-strength alloy steel welding wire has a higher alloy element content, leading to a faster etching rate that is difficult to control, often resulting in over-corrosion. Furthermore, metallographic sample preparation for metal wires is challenging. Small-diameter wires, especially those less than 2 mm in diameter, are prone to tipping during the mounting process, sometimes requiring repeated hot mounting to obtain cross-sectional metallographic samples. Utility Model Content

[0003] The purpose of this invention is to provide a clamp for electrochemical assisted etching of metal wires, which can quickly clamp wire samples and accommodate multiple sets of samples, improve the efficiency of metallographic sample preparation of metal wires, and accelerate or slow down the etching rate of the samples, thus solving the problems existing in the background art.

[0004] The technical solution of this utility model is: An electrochemical-assisted etching fixture for metal wire includes a base, fastening pins, and a metal clip. The base has several through holes, with a larger circular hole at the top, a conical hole in the middle, and a smaller circular hole at the bottom. The metal clip is fixed in the circular hole at the bottom of the base. The fastening pins are threaded into the larger circular hole and the conical hole at the top and middle of the base, respectively. The center of the fastening pins and the metal clip are respectively provided with a central hole that matches the wire sample.

[0005] The fastening screw has a hexagonal head at the top, external threads in the middle, and a tapered shape at the bottom.

[0006] The cone shape below the fastening pin is composed of several claws.

[0007] The taper of the chuck matches the tapered hole in the middle of the base.

[0008] The cone shape below the fastening pin consists of three claws.

[0009] When using this invention, the wire sample is inserted from the center hole of the metal clip into the center hole of the fastening nail, and then the fastening nail is tightened. The claws below the fastening nail are constricted by the conical hole and thus clamp the wire sample. During the experiment, the metal clip and the wire sample are used as a galvanic cell and etched with nitric acid alcohol.

[0010] The beneficial effects of this utility model are: it can realize the rapid mounting of wire samples and can accommodate multiple sets of samples, thereby improving the efficiency of metallographic sample preparation of metal wires; by forming a galvanic cell with the wire sample through the metal clip, the erosion rate of the sample can be effectively accelerated or slowed down, and the occurrence of pitting, over-erosion, and indistinct grain boundaries during the erosion process can be effectively controlled, thereby obtaining a better corrosion effect. Attached Figure Description

[0011] Figure 1 Metallographic images of annealed low-temperature high-manganese steel welding wire before and after electrochemical-assisted etching method; Figure 2 Metallographic images of low-temperature high-manganese steel welding wire in the drawn state before and after electrochemical-assisted etching method; Figure 3. Metallographic images of 380kg alloy steel welding wire before and after electrochemical-assisted etching method; Figure 4 Schematic diagram of metallographic sample preparation and electrochemical-assisted etching fixture for metal wires; Figure 5 Schematic diagram of metal wire sample mounting; Figure 6 Cross-sectional view of metallographic sample preparation and electrochemical-assisted etching fixture for metal wire; In the diagram: 1. Base; 2. Fastening nail; 3. Metal clip; 4. Wire sample; 5. Nail head; 6. Thread; 7. Claw. Detailed Implementation

[0012] The present invention will be further described below with reference to the accompanying drawings and examples.

[0013] See attached document Figure 4 , 5 6. A clamp for electrochemical assisted etching of metal wire, comprising a base 1, fastening pins 2 and metal clamping blocks 3. The base 1 is provided with several through holes, the upper part of which is a larger round hole, the middle part is a conical hole, and the lower part is a smaller round hole. The metal clamping blocks 3 are fixed in the round hole at the lower part of the base 1. The fastening pins 2 are threadedly connected to the larger round hole and the conical hole at the upper and middle parts of the base 1. The fastening pins 2 and the metal clamping blocks 3 are respectively provided with a central hole that matches the wire sample 4.

[0014] In this embodiment, the base 1 has 4 to 8 through holes. The smaller circular hole at the bottom is adapted to the size of the metal clip 3. The fastening nail 2 has a nail head 5 with an internal hexagonal structure above it, a thread 6 in the middle, and a cone shape composed of three claws 7 below it. There is a circular hole in the center. The size of the nail head 5 matches the diameter of the circular hole in the upper part of the base 1, the thread 6 in the middle matches the internal thread of the circular hole in the upper part of the base 1, and the slope of the three claws 7 matches the conical hole in the base 1. The metal clip 3 has a circular hole in the middle, the size of which is consistent with the wire sample 4. At the same time, the metal clip 3 and the wire sample 4 can form a galvanic cell, thereby realizing electrochemical assisted etching of the sample.

[0015] For wire sample 4 with a slow corrosion rate, the metal clip 3 can be made of a weaker metallic material, Cu or Sn, as the positive electrode of the galvanic cell to accelerate the corrosion of the sample; for wire sample 4 with a slow corrosion rate, the metal clip 3 can be made of a stronger metallic material, Al or Zn, as the negative electrode of the galvanic cell to slow down the corrosion of the sample.

[0016] In use, the wire sample 4 is inserted from the center hole of the metal clip 3 into the center hole of the fastening nail 2, and then the fastening nail 2 is tightened. The claw 7 below the fastening nail 2 is restrained by the tapered hole and shrinks, thereby clamping the wire sample 4. Example 1

[0017] Low-temperature high-manganese steel welding wire has stable chemical properties. For annealed low-temperature high-manganese steel welding wire, the traditional corrosion method is to use a 10% nitric acid alcohol solution for 5 minutes. The grain boundaries are not obvious. At the same time, due to long-term immersion, pitting corrosion is likely to occur and affect the observation of the microstructure.

[0018] The improved electrochemical corrosion method is as follows: a galvanic cell is constructed using a Cu metal block and a high-manganese steel welding wire sample, and corrosion is performed using 8% nitric acid alcohol for 3 minutes. (See attached image) Figure 1 As shown, after using the electrochemical-assisted etching method, the austenite grain boundaries are clear and the pitting sites disappear. Example 2

[0019] Low-temperature high-manganese steel welding wire has stable chemical properties. For drawn low-temperature high-manganese steel welding wire, the traditional corrosion method is to use a 10% nitric acid alcohol solution for 5 minutes. However, the twinned structure is not clear, and prolonged immersion can easily cause pitting corrosion and affect the observation of the structure.

[0020] The improved electrochemical corrosion method is as follows: a galvanic cell is constructed using a Cu metal block and a high-manganese steel welding wire sample, and corrosion is performed using 8% nitric acid alcohol for 2 minutes. (See attached image) Figure 2 As shown, after using the electrochemical-assisted etching method, the austenite grain boundaries and twin structures are clear, and the pitting sites disappear. Example 3

[0021] 80kg grade welding wire has a high alloy content and a fast corrosion rate. Traditional corrosion methods use a 4% nitric acid alcohol solution to corrode for 5-10 seconds. The corrosion process is difficult to control, and over-corrosion is likely to occur, resulting in darker colors in the metallographic photographs and making it difficult to distinguish the metallographic structure.

[0022] The improved electrochemical corrosion method involves using a Zn metal block and a high-manganese steel welding wire sample to form a galvanic cell, and then etching the sample with 4% nitric acid alcohol for 20-30 seconds. (See attached image.) Figure 3 As shown, after using the electrochemical-assisted etching method, the metallographic images are lighter in color and the microstructure is clearer.

[0023] A specific embodiment of the clamp is as follows: The base 1 has a diameter of 30mm and a height of 23mm. It contains 6 sets of through holes. The larger hole at the top has a diameter of 9mm and a depth of 5mm. The threaded hole in the middle is an M8 thread with a depth of 10mm. The tapered hole has an upper diameter of 6mm, a lower diameter of 4.5mm, and a depth of 3mm. The smaller diameter hole on the lower side has a diameter of 6mm and a depth of 3mm.

[0024] The fastener 2 has a head 5 with a diameter of 8.5mm and a thickness of 3mm, an internal hexagonal socket with a specification of 5mm and a depth of 1mm, a thread 6 with a specification of M8 and a height of 8mm, a claw 7 with a lower diameter of 4mm, an upper diameter of 5.6mm, an overall height of 8mm, a cylindrical shape at the upper 3mm and a frustum shape at the lower 5mm, an inner hole with a diameter of 2.5mm and a depth of 12mm.

[0025] The metal card block 3 has a diameter of 4mm, a thickness of 3mm, and contains a 2.0mm through hole.

[0026] This embodiment is suitable for metallographic observation of 2.0mm wires, and can be used for wires with lengths of 8 to 15mm.

Claims

1. A clamp for electrochemical-assisted etching of metal wires, characterized in that: It includes a base (1), fastening pins (2) and metal clips (3). The base (1) has several through holes. The upper part of the through holes is a larger round hole, the middle part is a conical hole, and the lower part is a smaller round hole. The metal clips (3) are fixed in the round hole at the bottom of the base (1). The fastening pins (2) are threaded into the larger round holes and conical holes at the top and middle of the base (1). The center of the fastening pins (2) and the metal clips (3) are respectively provided with a center hole that matches the wire sample (4).

2. The clamp for electrochemical assisted etching of metal wires according to claim 1, characterized in that: The fastening nail (2) has a nail head (5) with an internal hexagonal structure on the top, an external thread (6) in the middle, and a tapered shape at the bottom.

3. A clamp for electrochemically assisted etching of metal wires according to claim 2, characterized in that: The cone shape below the fastening pin (2) is composed of several claws (7).

4. A clamp for electrochemically assisted etching of metal wires according to claim 3, characterized in that: The taper of the claw (7) matches the tapered hole in the middle of the base (1).

5. A clamp for electrochemical assisted etching of metal wires according to claim 2, characterized in that: The cone shape below the fastening pin (2) is composed of three claws (7).

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