Method for controlling hardness of 45 steel cylindrical pin

Abstract

A hardness control method for a 45 steel cylindrical pin comprises the following steps that firstly, an annular cooling water tower is installed, the temperature of 45 steel quenching liquid is strictly controlled through a thermometer, and the temperature of the quenching liquid is controlled within the range of 10 DEG C to 13 DEG C; 2, moving up and down and left and right in the product cooling process until the binding end of the raw material iron wire cannot be exposed out of the liquid level of the quenching agent and is completely cooled in the quenching agent; and 3, 100% hardness detection is carried out on the bundled end of the iron wire for the quenched and tempered product. According to the invention, the problem that the test conclusion is unqualified due to the fact that the hardness has partial soft points when the hardness test is submitted in the total inspection of the 45 steel cylindrical pin is effectively solved.

Description

Technical Field

[0001] This invention relates to a method for controlling the hardness of 45 steel cylindrical pins, belonging to the field of fastener processing technology. Background Technology

[0002] When submitting 45 steel cylindrical pins for hardness testing, it was found that some products had soft spots, and the test results were unqualified. See the table below for details.

[0003] The 45 steel cylindrical pins underwent hardness testing during production and all tests were passed. The presence of soft spots in some of these pins is due to issues with the quenching process control of the 45 steel raw material.

[0004] 1) The cooling rate of the product during the quenching process is too low, that is, the water temperature is too high. The general specification requires 10-40℃. When the water temperature is at the upper limit, it will affect the hardness of 45 steel during quenching, that is, soft spots will exist.

[0005] 2) Improper manual operation during product cooling, such as the wire binding end protruding from the quenching liquid surface during raw material quenching, can result in the upper part of the product not being quenched.

[0006] 3) During random sampling in process inspection, the hardness of the wire binding end at the top of the product was not sampled, which may result in soft spots. Summary of the Invention

[0007] The present invention aims to solve the technical problem of soft spots in the cylindrical pin portion of 45 steel.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A method for controlling the hardness of 45 steel cylindrical pins includes the following steps:

[0010] Step 1: Install a circulating cooling tower and use a thermometer to strictly control the temperature of the quenching liquid for 45 steel, keeping the quenching liquid temperature within the range of 10-13℃.

[0011] Step 2: During the cooling process, the product should move up, down, left, and right. The ends of the raw material wire binding should not protrude from the surface of the quenching agent, and the product should be completely cooled in the quenching agent.

[0012] Step 3: After quenching and tempering, test the hardness of the wire binding ends of the product 100%

[0013] The beneficial technical effects of adopting the above technical solution are:

[0014] This invention effectively solves the problem that when 45 steel cylindrical pins are submitted for hardness testing during final inspection, some soft spots exist, leading to unqualified test results. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. A method for controlling the hardness of a 45 steel cylindrical pin includes the following steps:

[0016] Step 1: Install a circulating cooling tower and use a thermometer to strictly control the temperature of the quenching liquid for 45 steel, keeping the quenching liquid temperature within the range of 10-13℃.

[0017] Step 2: During the cooling process, the product should move up, down, left, and right. The ends of the raw material wire binding should not protrude from the surface of the quenching agent, and the product should be completely cooled in the quenching agent.

[0018] Step 3: After quenching and tempering, test the hardness of the wire binding ends of the product 100%

[0019] After processing using this method, the test results were satisfactory, as detailed in the table below.

[0020]

[0021]

[0022]

[0023]

[0024]

Claims

1. A method for controlling the hardness of a 45 steel cylindrical pin, characterized in that: It includes the following steps: Step 1: Install a circulating cooling tower and use a thermometer to strictly control the temperature of the quenching liquid for 45 steel, keeping the quenching liquid temperature within the range of 10-13℃. Step 2: During the cooling process, the product should move up, down, left, and right. The ends of the raw material wire binding should not protrude from the surface of the quenching agent, and the product should be completely cooled in the quenching agent. Step 3: After quenching and tempering, test the hardness of the wire binding ends of the product 100%

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