Stelmor air-cooled line controlled cooling process for improving structure and performance of spring steel 55SiCrA coil rod

A Steyrmore air-cooled, spring steel technology, used in manufacturing tools, metal processing equipment, workpiece cooling devices, etc., can solve the problem that the strength and hardness cannot meet the requirements, and it is prone to martensite and bainite, soxhlet. The problem of limited sintering rate, etc., can increase the sorbite rate, reduce the existence of retained austenite, and avoid the increase of hardness.

Active Publication Date: 2017-05-31
ZENITH STEEL GROUP CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is: in order to solve the abnormal structures such as martensite and bainite that are easy to appear in the cooling process of 55SiCrA spring steel in the prior art, the material area reduction rate is not high, the sorbite rate is limited, and the s

Method used

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  • Stelmor air-cooled line controlled cooling process for improving structure and performance of spring steel 55SiCrA coil rod
  • Stelmor air-cooled line controlled cooling process for improving structure and performance of spring steel 55SiCrA coil rod
  • Stelmor air-cooled line controlled cooling process for improving structure and performance of spring steel 55SiCrA coil rod

Examples

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Effect test

Embodiment 1

[0015] The rolling mill produces φ16mm55SiCrA, the rolling temperature is 990°C, the temperature of the sizing mill is 820°C, and the spinning temperature is 790°C. The first 10 insulation covers on the Stelmore air-cooled line are opened, the last two insulation covers are opened, and the middle insulation covers are closed. Control the air volume of 1 to 3 fans at 85%, 4 to 5 at 30%, 6 to 7 at 50%, and the rest of the fans off. The speed of the roller table is shown in Table 1 below.

[0016] Table 1 Corresponding roller table speed for each insulation cover of φ16mm55SiCrA Stelmo air-cooled line

[0017]

[0018] The corresponding relationship between the end temperature of each fan and time measured on site is as follows: figure 1 As shown, under the air cooling of the first three fans, the cooling speed of the wire rod is about 8°C / s, the lowest temperature at the third blower is 680°C, the return temperature of the fourth and fifth fans is 25°C, and the temperature o...

Embodiment 2

[0021] The steel rolling mill produces φ16mm55SiCrA, the rolling start temperature is 980°C, the temperature of the sizing mill is 810°C, and the spinning temperature is 800°C. The first 10 insulation covers on the Stelmore air-cooled line are opened, the last two insulation covers are opened, and the middle insulation covers are closed. The air volume of 1 to 3 fans is 85%, 4 to 5 is 28%, 6 to 7 is 50%, and the rest of the fans are turned off. The speed of the roller table is shown in Table 1.

[0022] On-site measurements show that the cooling speed of the wire rod is about 6°C / s under the air cooling of the first two fans, the lowest temperature at the third fan is 700°C, the return temperature of the fourth and fifth fans is 20°C, and the temperature of the sixth fan is 20°C. The cooling rate from the fan to the closing of the heat preservation cover is about 1.5°C / s, the temperature entering the heat preservation cover is 680°C, the cooling rate inside the heat preservati...

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Abstract

The invention provides a stelmor air-cooled line controlled cooling process for improving the structure and performance of a spring steel 55SiCrA coil rod. The controlled cooling process includes the steps that the finish rolling temperature is 790-820 DEG C, the blast capacity of the front three draught fans is controlled to meet the requirement that under various specifications, the lowest temperature of the third draught fan is within 680-710 DEG C, and the cooling speed of the front two draught fans is controlled within 5-13 DEG C per second; the blast capacity of a fourth draught fan and a fifth draught fan is controlled to make the coil rod temperature rise by 10-50 DEG C; the blast capacity of a sixth draught fan and follow-up draught fans is controlled to make the cooling speed within 3 DEG C per second, after the coil rod temperature is within 670-700 DEG C, thermal insulation covers are closed, and all the thermal insulation covers are opened before the temperature range; the cooling speed in the each thermal insulation cover is controlled at 0.8-2.0 DEG C per second, the draught fans are closed, the final two thermal insulation covers are opened, and the temperature of the coil rod discharged from each thermal insulation cover is 580-630 DEG C. In the process, the 55SiCrA coil rod is uniform in structure and composed of pearlite and a small amount of ferrites, under the various specifications, the percentage of area reduction can reach 60 or above, the sorbitizing rate and the plasticity reach high standards, and the strength, the hardness and the like can meet the performance requirement.

Description

technical field [0001] The invention relates to a controlled cooling process method of spring steel 55SiCrA, in particular to a Stelmo air-cooled line controlled cooling process for improving the microstructure and performance of spring steel 55SiCrA wire rods. Background technique [0002] 55SiCrA spring steel wire rod is a high-value-added high-quality steel for the production of automobile suspension springs. The suspension springs undergo reciprocating compression movements during automobile driving and play the role of buffering and shock absorption. Therefore, 55SiCrA spring steel is required for use. It has high anti-shock performance, high mechanical properties and high fatigue life, and puts forward more stringent standards for the chemical composition, inclusions, structure and plasticity of the wire rod. [0003] In order to achieve higher performance requirements, the final microstructure and performance of the wire rod can be affected by controlling the cooling ...

Claims

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Application Information

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IPC IPC(8): B21B45/02C21D1/00
CPCB21B45/0203C21D1/00C21D2211/005C21D2211/009
Inventor 陈志亮万文华滕力宏甄玉赵阳韩健仝太钦
Owner ZENITH STEEL GROUP CORP
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