KR20220118877A - Method for hardening pulling-straightening roller through thermal treatment - Google Patents

Abstract

The present invention relates to a heat treatment method of a tension roller, and more particularly, to a heat treatment method of a full-hardening tension roller. The heat treatment method comprises the following steps of: carrying out integral quenching and integral tempering on the tension roller to perform integral hardening on the tension roller; and carrying out end tempering on non-working areas at both ends of a working roll of the tension roller to ensure that the hardness of the non-working areas at both ends of the working roll is smaller than that of a working area of the working roll and the toughness of the non-working areas is greater than that of the working area. According to the heat treatment method of the full-hardening tension roller, which is provided by the present invention, the tension roller is completely hardened, the hardness of a working surface reaches HRC61-63, the working surface has high hardness, wear resistance and long service life, and the surface quality of a plate can be effectively improved. The service life of the plate is more than twice of that of a common tension roller, thereby reducing production costs.

Description

Heat treatment method of full hardening tension roller

The present invention relates to a heat treatment method for a kind of tension roller, and more particularly, to a heat treatment method for a full hardening tension roller.

The tension level is a very important equipment in the pickling line of the cold rolling mill, and its main role is to stretch, bend, and straighten the sheet strip plate shape, thereby causing the sheet strip to achieve a straightening effect, greatly improving the straightness of the sheet strip. Thus, a high-quality plate can be obtained. Although the tension leveler is mainly based on tension rollers, there are disadvantages in that the service life of the tension roller is short, it needs to be replaced frequently, and it affects production and increases the production cost.

Yiwang's tension roller mainly uses heat treatment to increase the surface hardness to ensure its service life, and there are two methods:

One is AISI-D2 or Cr12MoV1, the manufacturing process includes: blank → roughing → tempering up to HRC30-34 → precision machining pre-hold size → hardening up to HRC63-65 surface quenching → precision machining and polishing → finished product and shipment. Even if the surface hardness reaches HRC63-65, the wear resistance is poor, it is not durable, and the service life is short, and it should be replaced normally every 3-6 months.

The other one is used for 60CrMo, the process procedure is: blank→priming→tempering treatment HB240-280(HRC22-28)→hardness HS85-95(HRC62-67) surface quenching→quenching layer depth 2-3mm→surface hardening Includes chrome plating single side 0.08-0.10 mm (hard chrome plating layer). Although the wear resistance is increased, the hard chrome plating layer wears out after a certain period of use and requires a new hard chrome plating, so the cost is high, and the hard chrome plating layer is easily peeled off, affecting the surface quality of the sheet material straightening.

In order to solve the above problems, the present invention provides a heat treatment method for a full hardening tension roller that can harden the entire inside of a kind of tension roller and effectively improve the plate material surface quality as well as high hardness, abrasion resistance, and extended service life Therefore, the specific technical solution is as follows:

The heat treatment method of the full hardening tension roller includes: performing full quenching and full tempering of the tension roller, performing full hardening of the tension roller, and then tempering the end of the non-working section at both ends of the work roll of the tension roller and making the hardness of the non-working section at both ends of the work roll smaller than the hardness of the working section of the work roll, and making the toughness of the non-working section larger than the toughness of the working section.

Preferably, the entire quenching includes preheating, high temperature heating, quenching and low tempering, the temperature during the high temperature heating is 1015 to 1030 ℃, the keeping time is 20 to 25 min, and 70 to 100 ℃ of air during the quenching The furnace is cooled, and the row tempering is performed twice.

Preferably, the preheating proceeds in sequence, and includes a first constant temperature preheating, a second constant temperature preheating, and a third constant temperature preheating in which the temperature is sequentially increased: the first constant temperature preheating temperature is 350∼450°C, and the keeping time is 2∼3h to be. The secondary constant temperature preheating temperature is 550 ~ 650 ℃, and the keeping time is 1 ~ 2h. The third constant temperature preheating temperature is 750∼850°C, and the keeping time is 0.5∼1h.

Among them, the temperature difference between the first constant temperature preheating and the second constant temperature preheating and the second constant temperature preheating and the third constant temperature preheating is on average between 180°C and 220°C.

Preferably, the low tempering temperature is 150 ~ 200 ℃, the keeping time is 2 ~ 4h.

Preferably, the whole tempering includes tempering preheating and high temperature tempering. The temperature at the time of the preheating of the tempering is 340 ~ 380 ℃, the keeping time is 2 ~ 3h. The temperature at the time of the high temperature tempering is 500 ~ 515 ℃, the keeping time is 2 ~ 3h.

Preferably, the air after the low tempering is cooled to room temperature.

Preferably, the end tempering includes tempering preheating and high temperature tempering. The temperature at the time of the preheating of the tempering is 340 ~ 380 ℃, the keeping time is 2 ~ 3h. The temperature at the time of the high-temperature tempering is 580 to 590° C., and the keeping time is 2 to 3 h.

Compared with Lee Wang's technique, the present invention has the following advantageous effects:

The heat treatment method of the full hardening tension roller provided by the present invention hardens all the tension rollers and makes the hardness of the working surface reach HRC61-63, so that high hardness, abrasion resistance, service life extension, as well as the surface quality of the plate material are effectively improved. can be improved By reaching more than twice the service life of ordinary tension rollers, the production cost can be lowered.

1 is a diagram of the entire quenching procedure for the full hardening tension roller.
Figure 2 is a diagram of the entire tempering procedure for the full hardening tension roller.
3 is an end tempering procedure diagram for a full hardening tension roller.
4 is a hardness distribution diagram of the full hardening tension roller.
5 is a detection view of a full hardening tension roller having a diameter of 16;
6 is a top plan view of the full hardening tension roller lateral surface.
Fig. 7 is a top plan view of the full hardening tension roller lateral 1/2R position surface.
Fig. 8 is a top plan view of the full hardening tension roller lateral center position surface;
9 is a top plan view of the longitudinal surface of the pull hardening tension roller.
Fig. 10 is a top plan view of the surface at 1/2R longitudinal direction of the full hardening tension roller.
11 is a top plan view of the longitudinal center position surface of the pull hardening tension roller;
12 is a local inspection view of the pull hardening tension roller.

In conjunction with the bankruptcy, the present invention will be described in further detail.

1 to 12, in the heat treatment method of the full hardening tension roller, first, the tension roller is fully quenched and fully tempered to harden the tension roller, and then the tension roller at both ends of the work roll. It includes a procedure of end-tempering the non-working section to make the hardness of the non-working section at both ends of the work roll smaller than the working section hardness of the work roll, and then making the toughness of the non-working section larger than the toughness of the working section.

The full hardening mentioned in the present invention matches the hardness of the surface and the core of the tension roller, and realizes hardening of the whole. For example, when using a diameter 5 for a tension roller with a diameter of 16, a tension roller with a diameter of 5 Hardness does not change even after use, maintaining HRC61~63, and it can be used by repeatedly modifying the roll. Because it can be used in the latitude, the cost of the tension roller can be greatly reduced.

The tension roller includes a work roll and a connecting shaft installed at both ends of the work roll and having a smaller diameter than the work roll. The work roll includes a working section and a non-working section, and the non-working section is located at both ends of the work roll. The working section of the work roll is used for sheet straightening.

Full quenching is:

Includes preheating, high temperature heating, quenching and low tempering. During high-temperature heating, the temperature is 1015~1030℃, the keeping time is 20~25min, the air is cooled to 70~100℃ during quenching, and low tempering is performed twice.

Among them, low tempering is performed twice.

In one or more embodiments, the preheating proceeds in sequence, and includes a first constant temperature preheating in which the temperature is sequentially increased, a second constant temperature preheating, and a third constant temperature preheating: the first constant temperature preheating temperature is 350 to 450°C, and the keeping time is 2 ～3h. The secondary constant temperature preheating temperature is 550~650℃, and the keeping time is 1~2h. The 3rd constant temperature preheating temperature is 750~850℃, and the keeping time is 0.5~1h.

In one or more embodiments, the temperature difference between the first constant temperature preheating and the second constant temperature preheating and the second constant temperature preheating and the third constant temperature preheating is on average between 180 and 220°C.

In at least one embodiment, the low tempering temperature is 150-200° C., and the keeping time is 2-4 h.

In one or more embodiments, the overall tempering includes: tempering preheat and high temperature tempering. The temperature during preheating of tempering is 340~380℃, and the time is 2~3h. The temperature at the time of high temperature tempering is 500~515℃, and the time is 2~3h.

In one or more embodiments, the air after low tempering is cooled to room temperature.

In one or more embodiments, end tempering includes: tempering preheat and high temperature tempering. The temperature during preheating of tempering is 340~380℃, and the time is 2~3h. The temperature during high-temperature tempering is 580~590℃, and the time is 2~3h.

The heat treatment method of the full hardening tension roller is used for the heat treatment of the tension roller made of tool steel, and the tool steel includes AISI-D2, Cr12MoV1, D2ESR, and the like.

A full hardening tension roller, the tension roller includes a connecting shaft that is installed at both ends of the work roll and the work roll and has a diameter smaller than that of the work roll. It is located at both ends and connected to the connecting shaft, and the hardness of the working section and the connecting shaft of the work roll is HRC61~63, and the hardness of the non-working section is HRC50~55.

The processing method of the full hardening tension roller:

Blank roughing → total quenching and total tempering, hardness HRC61-63 or higher → non-working sections at both ends of the work roll up to HRC50-55, including tempering → priming → precision machining → grinding → packaging → shipping.

As shown in Fig. 4, the cross section of both ends of the work roll is a non-working section at a position of 20-50 mm in the inner direction, and the non-working section of both ends of the work roll is tempered to HRC50-55.

The quench layer depth reaches 100%. Rough machining is performed using a lathe, and precision machining is performed using a grinder.

1 to 3, the heat treatment method of the pull hardening tension roller includes the following procedures:

S1. Preheating, 1st constant temperature Preheating temperature is 350~450℃, and keeping time is 2~3h.

S2. Preheating, 2nd constant temperature Preheating temperature is 550~650℃, and keeping time is 1~2h.

S3. Preheating, 3rd constant temperature Preheating temperature is 750~850℃, and keeping time is 0.5~1h.

S4. The temperature during high-temperature heating and high-temperature heating is 1015-1030℃, and the keeping time is 20-25min.

S5. Quenching, air cooled to 70-100℃.

S6. Low tempering, low tempering temperature is 150~200℃, keeping warm time is 2~4h, low tempering is performed twice.

S7. Cool, cool the air to room temperature.

S8. The temperature during all tempering and preheating of tempering is 340~380℃, and the keeping time is 2~3h.

S9. The temperature for all tempering and high-temperature tempering is 500-515℃, and the keeping time is 2-3h.

S10. Cooling, cooling the whole air to room temperature.

S11. The temperature during end tempering and preheating of tempering is 340~380℃, and the keeping time is 2~3h.

S12. During end tempering and high temperature tempering, the temperature is 580~590℃, and the keeping time is 2~3h.

S13. Cool, cool the air to room temperature.

Example

This embodiment includes eleven embodiments, and the tension roller is ∮16×981. The difference between each embodiment is the constant temperature preheating temperature and the keeping time, the high temperature heating temperature and the keeping time, the quenching temperature and the keeping time, the low tempering temperature and the keeping time, the whole tempering temperature and the keeping time, and the end tempering temperature and the keeping time.

1, 2, and 3 distribution display survey points are shown in FIGS. 5 and 6 . As can be seen from FIGS. 5 and 6, the surface hardness distribution of the tension roller treated by the heat treatment method of the full hardening tension roller is uniform, the corrected plate surface is smooth, there is no color difference, and the color uniformity is guaranteed. can

turn S11th constant temperature preheating S21st constant temperature preheating S31st constant temperature preheating S4 high temperature heating S5 quenching S6 Low Tempering S8 Full Tempering Preheat S9 Full High Temperature Tempering S11 Tempering Preheat S12 high temperature tempering Example 1 350℃
2.8h 550℃
2h 750℃
0.5h 1015℃
25min 70℃ 150℃
4h 350℃
3h 500℃
3h 350℃
3h 580℃
3h Example 2 360℃
2h 560℃
1.2h 760℃
0.6h 1016℃
24min 75℃ 165℃
3.8h 345℃
2.8h 505℃
2.5h 360℃
2.8h 582℃
3h Example 3 370℃
3h 570℃
1.5h 770℃
0.7h 1017℃
23min 80℃ 180℃
3.6h 350℃
2.7h 510℃
2h 370℃
2.7h 584℃
2.8h Example 4 380℃
2.2h 580℃
1.9h 780℃
0.8h 1019℃
25min 85℃ 200℃
2h 355℃
2.6h 515℃
3h 380℃
2.6h 586℃
2.5h Example 5 390℃
2.5h 590℃
1.5h 790℃
0.6h 1020℃
20min 90℃ 170℃
2.5h 360℃
2.5h 506℃
2h 390℃
2.5h 588℃
2h Example 6 400℃
2h 600℃
2h 800℃
1h 1021℃
20min 95℃ 175℃
3.5h 365℃
2.2h 508℃
2.2h 340℃
2.2h 580℃
2.6h Example 7 410℃
2.6h 610℃
1.6h 810℃
0.8h 1022℃
23min 100℃ 190℃
3h 370℃
2h 512℃
2h 345℃
2h 590℃
2.5h Example 8 420℃
3h 620℃
1h 820℃
0.5h 1025℃
22min 78℃ 160℃
3.5h 375℃
2.3h 514℃
2.3h 355℃
2.3h 584℃
2.4h Example 9 430℃
2.3h 630℃
1.8h 830℃
1h 1028℃
22min 86℃ 185℃
2.5h 380℃
2.1h 503℃
3h 375℃
2.1h 586℃
2h Example 10 440℃
2.9h 640℃
1h 840℃
0.5h 1029℃
23min 98℃ 155℃
3.5h 360℃
2h 506℃
2.6h 365℃
2h 588℃
2.3h Example 11 450℃
2h 650℃
2h 850℃
0.6h 1030℃
21min 93℃ 195℃
2.5h 355℃
2.1h 509℃
3h 360℃
2.1h 590℃
2.1h

The full hardening tension roller is applied to the narrow and wide panel tension leveler equipment, with a diameter of Ψ16mm～Ψ40mm, a length of L1450mm～L1700mm, heat treatment hardness of HRC61～63, and the quenching layer depth of the tension roller is 100% It can achieve full roller hardening, high wear resistance, long service life, and effectively improve the panel surface quality. In addition, it is very effective and can be used in the stainless, copper, and silicon steel industries.

The technical principle according to the present invention has been described above in conjunction with the specific examples. Such description is merely to help the understanding of the principles of the present invention, and is not intended to limit the protection scope of the present invention in any way. Based on this interpretation, it will be understood by those skilled in the art that other specific embodiments of the present invention can be imagined without creative labor, and such methods should fall within the protection scope of the claims of the present invention.

Claims (8)

As a heat treatment method for a full hardening tension roller,
After all hardening of the tension roller is performed by performing full quenching and full tempering on the tension roller, tempering is performed on the ends of the non-working section at both ends of the work roll of the tension roller, A heat treatment method of a full hardening tension roller comprising a procedure of making the hardness of the non-working section smaller than the hardness of the working section of the work roll, and making the toughness of the non-working section larger than the toughness of the working section. According to claim 1,
The total quenching is:
Includes preheating, high temperature heating, quenching and low tempering procedures, the temperature during the high temperature heating is 1015 to 1030 ℃, the keeping time is 20 to 25 min, cooling the air to 70 to 100 ℃ during the quenching, the low tempering A heat treatment method for a full hardening tension roller that is performed twice. 3. The method of claim 2,
The preheating proceeds in sequence, and includes a first constant temperature preheating, a second constant temperature preheating, and a third constant temperature preheating in which the temperature is sequentially increased,
The first constant temperature preheating temperature is 350~450℃, and the keeping time is 2~3h,
The secondary constant temperature preheating temperature is 550 ~ 650 ℃, the warming time is 1 ~ 2h,
The third constant temperature preheating temperature is 750 ~ 850 ℃, the keeping time is 0.5 ~ 1h,
Heat treatment method of full hardening tension roller. 4. The method of claim 3,
The temperature difference between the first constant temperature preheating and the second constant temperature preheating and the second constant temperature preheating and the third constant temperature preheating is between 180 and 220°C on average,
Heat treatment method of full hardening tension roller. 4. The method of claim 2 or 3,
The low tempering temperature is 150 ~ 200 ℃, the keeping time is 2 ~ 4h,
Heat treatment method of full hardening tension roller. 4. The method of claim 2 or 3,
The whole tempering includes tempering preheating and high temperature tempering procedure,
The temperature at the time of the preheating of the tempering is 340~380℃, the keeping time is 2~3h,
The temperature at the time of the high temperature tempering is 500 ~ 515 ℃, the keeping time is 2 ~ 3h,
Heat treatment method of full hardening tension roller. 3. The method of claim 2,
A heat treatment method of a full hardening tension roller for cooling the air after the low tempering to room temperature. According to claim 1,
The end tempering includes a tempering preheating and a high temperature tempering process,
The temperature at the time of the preheating of the tempering is 340~380℃, the keeping time is 2~3h,
The temperature at the time of the high temperature tempering is 580 ~ 590 ℃, the keeping time is 2 ~ 3h,
Heat treatment method of full hardening tension roller.

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