阅读说明：本技术 一种控制细长类h13矫直辊双频淬火变形的工艺 (Process for controlling double-frequency quenching deformation of slender H13 straightening roller ) 是由 李文 彭元飞 于 2021-09-26 设计创作，主要内容包括：本发明公开了一种控制细长类H13矫直辊双频淬火变形的工艺,具体为：对H13矫直辊进行消应力,消应力后进行校直,之后重复进行消应力和校直,直到消应力后跳动变形≤1mm；选择合适的淬火工频和中频感应器；制定工频和中频感应器的淬火温度,淬火过程中H13矫直辊以42mm/min的速度下降,开始淬火时H13矫直辊不进行自转,随着工件的下移,当发现H13矫直辊出现轻微变形时,旋转H13矫直辊使其始终位于工频和中频感应器中心位置,如此一直进行,直至淬火完成。通过对四个淬火环节进行工艺创新,使细长类H13矫直辊的双频淬火变形大大降低,辊面硬度均匀性也得到了提高。(The invention discloses a process for controlling double-frequency quenching deformation of a slender H13 straightening roller, which comprises the following steps: stress relief is carried out on the H13 straightening roll, straightening is carried out after stress relief, then stress relief and straightening are carried out repeatedly until the jumping deformation is less than or equal to 1mm after stress relief; selecting a proper quenching power frequency and medium frequency inductor; setting the quenching temperature of the power frequency and medium frequency inductors, lowering the H13 straightening roll at 42mm/min during quenching, starting quenching without the H13 straightening roll rotating, moving the workpiece downwards, rotating the H13 straightening roll to make the H13 straightening roll always positioned at the center of the power frequency and medium frequency inductors when the H13 straightening roll is slightly deformed, and so on until quenching is finished. By carrying out technological innovation on four quenching links, the double-frequency quenching deformation of the slender H13 straightening roll is greatly reduced, and the hardness uniformity of the roll surface is also improved.)

1. A process for controlling double-frequency quenching deformation of a slender H13 straightening roller is characterized by comprising the following steps:

step 1, stress relief is carried out on an H13 straightening roller, straightening is carried out after stress relief, then stress relief and straightening are carried out repeatedly until the jumping deformation is less than or equal to 1mm after stress relief;

step 2, selecting a proper quenching power frequency and medium frequency inductor;

step 3, setting the quenching temperature of the power frequency and medium frequency inductor;

and 4, after the step 3, quenching, wherein the H13 straightening roll is lowered at the speed of 42mm/min in the quenching process, the H13 straightening roll does not rotate when the quenching is started, and the H13 straightening roll is rotated to be always positioned at the central position of the power frequency and medium frequency inductor along with the downward movement of the workpiece when the H13 straightening roll is slightly deformed, and the process is carried out until the quenching is finished.

2. The process for controlling the double-frequency quenching deformation of the slender H13-like straightening roll as claimed in claim 1, wherein the step 1 specifically comprises the following steps: placing an H13 straightening roller in a trolley type resistance furnace, heating to 650 ℃ at the speed of 80 ℃/H, preserving heat for 5-6H, then, cooling to 300 ℃ in a power-off furnace, discharging, straightening, placing the straightening roller in the furnace after straightening until the runout deformation is less than or equal to 2mm, continuously adopting the same process for stress relief, cooling to 300 ℃ in the power-off furnace after heat preservation is finished, discharging, straightening, placing the straightening roller in the furnace after straightening until the runout deformation is less than or equal to 2mm, and then, repeatedly performing stress relief and straightening until the runout deformation is less than or equal to 1mm after stress relief.

3. The process for controlling the double-frequency quenching deformation of the slender H13-like straightening roll as claimed in claim 1, wherein in the step 2, the quenching inductors are selected so that the diameters of the inductors at the power frequency and the medium frequency are 100mm larger than that of the H13 straightening roll.

4. The process for controlling the double-frequency quenching deformation of the slender H13-like straightening roll as claimed in claim 1, wherein in the step 3, the quenching temperature of the industrial frequency inductor is 750-800 ℃, and the quenching temperature of the medium frequency inductor is 1030-1050 ℃.

Technical Field

The invention belongs to the technical field of heat treatment induction quenching of straightening rollers, and particularly relates to a process for controlling double-frequency quenching deformation of a slender H13 straightening roller.

Background

The H13 straightening roll is a roll which is commonly used in a hot-rolled sheet strip straightener, and the surface of the roll needs high wear resistance and needs a certain hardening layer depth. Therefore, the straightening roller generally needs to be subjected to induction quenching to reach the required hardness and layer depth, the hardening layer depth of the ordinary medium-frequency induction quenching is about 6-8mm, and a double-frequency quenching process is needed to obtain a deeper hardening layer, which can reach 10-15 mm. However, the deep hardening layer will cause a certain jumping deformation after the straightening roller is quenched to be out of tolerance, and particularly, the H13 straightening roller with a large slenderness ratio has huge deformation after being subjected to double-frequency quenching according to the conventional process and cannot be straightened.

Disclosure of Invention

The invention aims to provide a process for controlling double-frequency quenching deformation of a slender H13 straightening roller, so that the double-frequency quenching deformation of the slender H13 straightening roller is greatly reduced.

The technical scheme adopted by the invention is that the process for controlling the double-frequency quenching deformation of the slender H13 straightening roller is implemented by the following steps:

step 1, stress relief is carried out on an H13 straightening roller, straightening is carried out after stress relief, then stress relief and straightening are carried out repeatedly until the jumping deformation is less than or equal to 1mm after stress relief;

step 2, selecting a proper quenching power frequency and medium frequency inductor;

step 3, setting the quenching temperature of the power frequency and medium frequency inductor;

and 4, after the step 3, quenching, wherein the H13 straightening roll is lowered at the speed of 42mm/min in the quenching process, the H13 straightening roll does not rotate when the quenching is started, and the H13 straightening roll is rotated to be always positioned at the central position of the power frequency and medium frequency inductor along with the downward movement of the workpiece when the H13 straightening roll is slightly deformed, and the process is carried out until the quenching is finished.

The present invention is also characterized in that,

the step 1 specifically comprises the following steps: placing an H13 straightening roller in a trolley type resistance furnace, heating to 650 ℃ at the speed of 80 ℃/H, preserving heat for 5-6H, then, cooling to 300 ℃ in a power-off furnace, discharging, straightening, placing the straightening roller in the furnace after straightening until the runout deformation is less than or equal to 2mm, continuously adopting the same process for stress relief, cooling to 300 ℃ in the power-off furnace after heat preservation is finished, discharging, straightening, placing the straightening roller in the furnace after straightening until the runout deformation is less than or equal to 2mm, and then, repeatedly performing stress relief and straightening until the runout deformation is less than or equal to 1mm after stress relief.

In the step 2, the diameters of the industrial frequency and medium frequency inductors are 100mm larger than the diameter of the H13 straightening roll when the quenching inductor is selected.

In step 3, the quenching temperature of the power frequency inductor is 750-.

The invention has the beneficial effects that: aiming at the heat treatment characteristic of the H13 material, firstly, the high temperature resistance of the material is utilized, so that the comprehensive mechanical property is not influenced when the stress is repeatedly eliminated at high temperature; secondly, the high hardenability of the steel plate can adopt a quenching mode of power frequency low-temperature preheating and medium-frequency high-temperature heating during double-frequency quenching, compared with the traditional quenching mode that two inductors are both used for high-temperature heating, the steel plate can greatly reduce quenching stress and reduce energy consumption, and the depth of a hardening layer of the straightening roll is not influenced; thirdly, the straightening roller is manually and properly adjusted to rotate in the quenching process, so that the straightening roller is positioned at the central position of the inductor and is uniformly heated, and further deformation caused by uneven heating due to too large swinging in the inductor after the straightening roller is deformed is avoided.

Drawings

FIG. 1 is a schematic diagram of H13 straightening roll dual frequency quenching according to the process of the present invention;

fig. 2 is a schematic diagram of H13 straightening roll double frequency quenching according to a conventional process.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

The invention relates to a process for controlling double-frequency quenching deformation of a slender H13 straightening roller, which is implemented by the following steps:

step 1, placing an H13 straightening roller in a trolley type resistance furnace, heating to 650 ℃ at a speed of 80 ℃/H, preserving heat for 5-6H, then cooling to 300 ℃ in a power-off furnace, discharging, straightening, wherein the straightening process can be executed according to corresponding operation rules according to different straightening devices, after straightening until the run-out deformation is less than or equal to 2mm, placing the straightening roller in the furnace, continuing to adopt the same process for stress relief, cooling to 300 ℃ in the power-off furnace after heat preservation, discharging, straightening, and placing the straightening roller in the furnace … … after straightening until the run-out deformation is less than or equal to 2 mm: stress relief, straightening, stress relief and … … are repeatedly carried out until the jumping deformation is less than or equal to 1mm after the stress relief is discharged, so that double-frequency quenching can be carried out, the reciprocating stress relief process can reduce the internal stress of the straightening roller to the maximum extent, and the stress accumulation in the quenching process is reduced, thereby achieving the purpose of controlling the deformation.

Step 2, when the quenching inductor is selected, the diameters of the industrial frequency inductor and the medium frequency inductor are both 100mm larger than the diameter of the H13 straightening roll, and the large inductor gap is used for reducing the heat sensitivity of the temperature to the inductor gap when a workpiece is heated, so that the heating is more uniform, and the heating deformation is reduced;

step 3, setting a quenching temperature, controlling the power frequency heating temperature at 750-; the medium frequency is mainly used for heating, the quenching temperature is ensured to be reached, and after the workpiece is heated by the double inductors, the workpiece is completely austenitized and can reach higher hardness through rapid cooling of water in the water spraying ring;

and 4, after the step 3, quenching, wherein the H13 straightening roll is lowered at the speed of 42mm/min in the quenching process, the H13 straightening roll does not rotate when the quenching is started, and the H13 straightening roll is rotated to be always positioned at the central position of the power frequency and medium frequency inductor along with the downward movement of the workpiece when the H13 straightening roll is slightly deformed, and the process is carried out till the quenching is finished, so that the uniform heating of the H13 straightening roll can be ensured, and the quenching deformation is reduced.

The invention mainly aims to solve the problem of large deformation after double-frequency induction quenching of a slender H13 straightening roller, and controls the deformation in the quenching process through the aspects of reciprocating stress relief before quenching, selection of a quenching inductor, control of quenching temperature and adjustment of a workpiece rotating mode in the quenching process. By carrying out technological innovation on four quenching links, the double-frequency quenching straightening roller has the beneficial effects different from the conventional quenching method under the comprehensive influence, so that the double-frequency quenching deformation of the slender H13 straightening roller is greatly reduced, and the hardness uniformity of the roller surface is also improved. After the H13 straightening roll with the slenderness ratio of more than or equal to 15 is subjected to double-frequency induction quenching, the quenching jumping deformation of the straightening roll is controlled within 3 mm.

Example 1

The H13 straightening roll product size adopted in the embodiment is as follows: φ 315X 4450/5506. The hardness of the roller body is HRC54-56, and the layer depth is 12-14 mm. The main components of the product are shown in table 1, and the basic parameters of the adopted double-frequency quenching transformer are shown in table 2;

TABLE 1H13 major Components of the straightener rolls

C	Si	Mn	Cr	Mo	V
						0.38	1.10	0.45	5.20	1.55	1.30

TABLE 2 basic parameters of double-frequency quenched transformer

The process of the invention is used for operation, as shown in figure 1, and comprises the following specific steps:

(1) stress relief before quenching

Placing an H13 straightening roller in a trolley type resistance furnace, heating to 650 ℃ at a speed of 80 ℃/H, preserving heat for 5-6H, then discharging from the furnace when the furnace is cooled to about 300 ℃ for straightening, straightening until the run-out deformation is less than or equal to 2mm, then placing the straightening roller in the furnace, continuing to adopt the same process for stress relief, discharging from the furnace when the furnace is cooled to about 300 ℃ after the heat preservation is finished, straightening until the run-out deformation is less than or equal to 2mm, and then placing the straightening roller in the furnace … …: stress relief, straightening, stress relief and … … are repeatedly carried out until the jumping deformation is less than or equal to 1mm after the stress relief is discharged, thus the double-frequency quenching can be carried out. Through repeated stress relief straightening at high temperature, various residual stresses of the workpiece can be greatly reduced, and finally the deformation control after quenching can be facilitated.

(2) Reasonable selection inductor

Since the heating temperature is more sensitive to the inductor gap, only a reduction in this sensitivity reduces the interaction between them. Therefore, the inductor with larger diameter can be selected, so that after the gap between the inductor and the roller body is increased, the sensitivity is reduced, the mutual influence is naturally reduced, after the micro deformation occurs, the temperature difference of high and low points is not too large, the deformation amount cannot be continuously and maliciously increased, and the range is kept within a certain range.

The middle frequency inductor with the diameter of 450mm and the power frequency inductor with the diameter of 450mm are selected according to the diameter of the straightening roll, compared with the conventional process, although the gap of the inductors is enlarged, the power frequency inductors only need to be heated at the temperature of about 700-800 ℃, so that the problem of insufficient heating temperature is solved, and the full power input of the middle frequency inductors in the gap can meet the quenching temperature range of 1030-1050 ℃.

(3) Selection of quenching temperature

Because the hardenability of the H13 material is high and the quenching temperature range is wide, the HRC54-56 hardness required by the drawing is not very high, and the hardness is easy to achieve. Therefore, the quenching temperature can be properly reduced, the power frequency heating temperature is controlled to be 700-800 ℃ for preheating, and the intermediate frequency heating temperature is controlled to be about 1030-1050 ℃, so that the quenching and heating functions are mainly realized. After the power frequency heating temperature is reduced, the deformation caused by high quenching temperature can be effectively avoided.

(4) Control of the manner of rotation of a workpiece

The uneven rotating clearance of the straightening roller in the heating process can cause great difference of quenching temperature. Only by uniform heating, the condition of hardness of a shade surface and a sun surface can be avoided, the gap is kept uniform, and the straightening roller can be directly heated and quenched without rotating in an inductor in the quenching process.

The descending speed of the straightening roller is 42mm/min, the straightening roller is directly quenched without rotating at first, the phenomenon that the gap is uneven due to the deformation of the roller body can occur in the quenching process, but the change condition of the gap between the roller body and the inductor needs to be closely checked in the whole process, once the straightening roller is not located at the central position of the inductor, the heating gap is uneven, a workpiece is rotated at a low speed immediately, the straightening roller is adjusted to the central position of the inductor, and the gap is kept uniform and continues to be heated. Therefore, the problem of uneven temperature can not occur in the whole quenching process, and the quenching deformation of the slender piece straightening roll is effectively reduced. The final test conditions are shown in table 3, and the data in table 3 are analyzed;

TABLE 3H13 test results for straightening rolls

Comparative example

The conventional double-frequency quenching process method for the H13 straightening roller with the specification comprises the following steps:

when the stress is eliminated before quenching, the straightening roller is arranged in a resistance furnace and heated to 550 ℃ at the speed of 80 ℃/h, the temperature is kept for 6h, then the furnace is stopped to cool to 300 ℃, and the straightening roller is taken out of the furnace and normally subjected to double-frequency quenching until the run-out deformation is less than or equal to 2 mm.

According to the process requirements, the diameter of a power frequency inductor is 375mm, the diameter of a medium frequency inductor is 375mm, a straightening roll is subjected to a normal double-frequency quenching process, the power frequency heating temperature is 1030 ℃, the medium frequency heating temperature is 1050 ℃, the workpiece quenching shift speed is 42mm/min, and the workpiece rotating speed is 20 r/min. All normal quenching processes are performed at first, when the workpiece is quenched to the middle position of the roller body, the fluctuation of the power frequency heating temperature and the medium frequency heating temperature is gradually found to be large, the fluctuation of the power frequency is from 1040 ℃ to 1020 ℃, the fluctuation of the medium frequency is from 1050 ℃ to 1030 ℃, and as the workpiece continues to move downwards in quenching, the temperature fluctuation is larger and larger, and the phenomenon that the gap is uneven due to the swinging of the workpiece in an inductor is obviously found. When the final quenching is close to the upper end of the roller body, the heating temperature in the two inductors fluctuates from 960-1070 ℃, the roller body is seriously bent and deformed, and the roller body can not be normally quenched and moved downwards along with the collision and friction between the roller body and the inductors. As shown in fig. 2. Quenching can be only marginally completed finally, the final detection result is shown in table 4, and the data in table 4 are analyzed;

table 4 test results of H13 straightening roll obtained by conventional quenching process

As can be seen from tables 3 and 4, by adopting the four-point process improvement method, compared with the traditional double-frequency quenching process method, the problem that the deformation of the slender H13 straightening roll is larger after double-frequency quenching is well solved, so that the surface hardness of the roll body is more uniform. The process method can be realized and has good effect.