阅读说明：本技术 一种提高40Cr大滚轮内孔表面淬硬层深度的方法 (Method for improving depth of hardening layer on surface of inner hole of 40Cr large roller ) 是由 刁中华 王勇 唐传昌 刘锋 张可可 于 2020-11-02 设计创作，主要内容包括：本发明公开了一种提高40Cr大滚轮内孔表面淬硬层深度的方法,该方法包括以下步骤：S1：将多个滚轮放入600℃的加热炉中,升温至800～850℃,恒温加热40～60min后取出；S2：将滚轮放入一定浓度的富顿水溶液介质中进行冷却；S3：将滚轮在S2所述的介质中来回摆动至少15s,静置2～5min后取出；S4：对S3取出滚轮表面进行观察,并对取出后的滚轮表面硬度进行检测,本发明提高了滚轮内、外圆的表面硬度,由原来的HRC40以下,提高至HRC50以上；平均内孔淬硬层深度达到3mm以上,大大改善了滚轮的耐磨性,提高了堆取料机用输送链条的使用寿命。(The invention discloses a method for improving the depth of a hardening layer on the surface of an inner hole of a 40Cr large roller, which comprises the following steps: s1: putting a plurality of rollers into a heating furnace at 600 ℃, heating to 800-850 ℃, heating at constant temperature for 40-60 min, and taking out; s2: placing the roller into a rich water solution medium with a certain concentration for cooling; s3: swinging the roller back and forth in the medium of S2 for at least 15S, standing for 2-5 min, and taking out; s4: the surface of the roller taken out of the S3 is observed, and the surface hardness of the roller taken out is detected, so that the surface hardness of the inner circle and the outer circle of the roller is improved to be more than HRC50 from the original HRC 40; the average depth of the inner hole hardening layer reaches more than 3mm, the wear resistance of the roller is greatly improved, and the service life of the conveying chain for the material piling and taking machine is prolonged.)

1. A method for improving the depth of a hardening layer on the surface of an inner hole of a 40Cr large roller is characterized by comprising the following steps:

s1: putting a plurality of rollers into a heating furnace at 600 ℃, heating to 800-850 ℃, heating at constant temperature for 40-60 min, and taking out;

s2: placing the roller into a rich water solution medium with a certain concentration for cooling;

s3: swinging the roller back and forth in the medium of S2 for at least 15S, standing for 2-5 min, and taking out;

s4: the surface of the roller taken out at S3 is observed, and the hardness of the surface of the roller taken out is detected.

2. The method for improving the depth of the hardened layer on the surface of the inner hole of the large 40Cr roller as claimed in claim 1, wherein: the concentration of the rich water in the step S2 is 1.5%, 2.0%, 2.5% and 3.0%.

3. The method for improving the depth of the hardened layer on the surface of the inner hole of the large 40Cr roller as claimed in claim 1, wherein: and S3, the direction of the axis of the roller is consistent with the direction of the back-and-forth swing of the roller, and the swing speed is 0.8-1.2 m/S.

4. The method for improving the depth of the hardened layer on the surface of the inner hole of the large 40Cr roller as claimed in claim 1, wherein: the heating furnace in the step S1 is a box-type furnace body of 45 kw.

5. The method for improving the depth of the hardened layer on the surface of the inner hole of the large 40Cr roller as claimed in claim 1, wherein: the diameter of the outer circle of the roller is 130mm, the diameter of the inner hole of the roller is 56mm, and the width of the roller is 64 mm.

Technical Field

The invention relates to the technical field of surface hardening layers of metal materials, in particular to a method for improving the depth of a hardening layer on the surface of an inner hole of a 40Cr large roller.

Background

Most of roller materials in the conveying chain for the stacker-reclaimer of cement and mining machinery adopt alloy structural steel 40Cr, and rollers roll and rub on the rail for a long time, so that the roller has better wear resistance and can ensure the expected service life of the chain for more than three years. The hardness of the roller is HRC48-54 after heat treatment, and the expected service life can be met. As the wall thickness of the roller reaches 35-55mm, the hardness of the roller is only about HRC40 after quenching by using common quenching oil, and the hardness of the roller can reach about HRC55 after quenching by using saline water, but axial cracks are easily formed on the surface of an inner hole, so that the roller is scrapped. For this reason, we must search for a quenching medium with a cooling rate between that of brine and quenching oil, and research is carried out to meet the related technical requirements.

Disclosure of Invention

In order to control the temperature of the quenching medium, the invention selects and purchases a closed cooler with a proper model according to the hourly production capacity of equipment and the capacity of a quenching medium cooling pool, meets the quenching hardness requirements of rollers with different shapes by adjusting the concentration of the Haofton quenching liquid, avoids the generation of cracks on the inner surface and the outer surface of the roller, and finally determines the concentration of the Haofton aqueous solution medium.

In order to solve the technical problems, the invention adopts the technical scheme that: a method for improving the depth of a hardening layer on the surface of an inner hole of a 40Cr large roller comprises the following steps:

s1: putting a plurality of rollers into a heating furnace at 600 ℃, heating to 800-850 ℃, heating at constant temperature for 40-60 min, and taking out;

s2: placing the roller into a rich water solution medium with a certain concentration for cooling;

s3: swinging the roller back and forth in the medium of S2 for at least 15S, standing for 2-5 min, and taking out;

s4: the surface of the roller taken out at S3 is observed, and the hardness of the surface of the roller taken out is detected.

Further, the concentration of the rich water in the step S2 is 1.5%, 2.0%, 2.5%, 3.0%.

Furthermore, in the step S3, the axis of the roller is consistent with the back-and-forth swinging direction of the roller, and the swinging speed is 0.8-1.2 m/S.

Further, the heating furnace in the step S1 is a 45kw box furnace body.

Further, the diameter of the outer circle of the roller is 130mm, the diameter of the inner hole of the roller is 56mm, and the width of the roller is 64 mm.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention improves the surface hardness of the inner circle and the outer circle of the roller from the original HRC40 below to the original HRC50 above; the average depth of the inner hole hardening layer reaches more than 3mm, the wear resistance of the roller is greatly improved, and the service life of the conveying chain for the material piling and taking machine is prolonged.

Drawings

FIG. 1 is a graph showing the hardness of the inner hole surface in the direction toward the excircle in the method for increasing the depth of the hardened layer on the inner hole surface of the 40Cr large roller in accordance with the present invention;

FIG. 2 is a graph showing the hardness distribution of the inner hole surface in the direction toward the outer circle in the method for increasing the depth of the hardened layer on the inner hole surface of the 40Cr large roller according to the present invention;

FIG. 3 is a schematic structural diagram of a roller in the method for increasing the depth of a hardened layer on the surface of an inner hole of a large 40Cr roller according to the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.

According to one embodiment of the invention, shown in combination with fig. 1-3, a method for increasing the depth of a hardening layer on the surface of an inner hole of a 40Cr large roller comprises the following steps: s1: putting a plurality of rollers into a heating furnace at 600 ℃, heating to 800-850 ℃, heating at constant temperature for 40-60 min, and taking out; s2: placing the roller into a rich water solution medium with a certain concentration for cooling; s3: swinging the roller back and forth in the medium of S2 for at least 15S, standing for 2-5 min, and taking out; s4: the surface of the roller taken out at S3 is observed, and the hardness of the surface of the roller taken out is detected.

The concentration of the rich water in the step S2 is 1.5%, 2.0%, 2.5% and 3.0%, the maximum hardness borne by the surface of the roller is obtained by cooling in the rich water with different concentrations, the axis of the roller in the step S3 is consistent with the direction of the reciprocating swing of the roller, the swing speed (0.8-1.2) m/S is increased by the consistent swing direction, the heating furnace in the step S1 is a 45kw box-type furnace body, and the heating is conveniently carried out by a 45kw box-type furnace body.

The diameter of the excircle of the roller is 130mm, the diameter of the inner hole is 56mm, the width of the roller is 64mm, the roller is cooled in a Haofton aqueous solution with a certain concentration, a hardness distribution condition table within the range of 5mm from the surface of the inner hole to the excircle direction is obtained after the roller is cut along the diameter, and a curve is drawn according to the point of HRC48 of the hardness of the detected position.

Taking a generatrix of an inner hole of the roller as an X axis, a middle point of the width as a Y axis, a vertical intersection point of the two axes as an original point, and drawing HRC48 hardening layer curves along the X axis with a right direction as a positive direction and a left direction as a negative direction as shown in figures 1 and 2 according to the insertion method of figures 1 and 2, and estimating that the average hardening layer depth of the inner hole reaches about 3mm, thereby completely meeting the requirement of 2mm abrasion.

The specific embodiment is as follows: placing the rollers into a 45KW box furnace with the furnace temperature of 600 ℃, heating to 820 ℃, keeping the temperature for 50min after reaching the temperature, and discharging:

(1) the roller is hooked out by a hook and put into a 1.5% concentration Haofton aqueous solution medium, the roller is rapidly swung back and forth in the medium at a swinging speed of about 1 m/s, the axis of the roller is ensured to be consistent with the swinging direction of the roller, so that the cooling speed of the inner hole of the roller is increased, the roller can be kept stand still for continuous cooling for 3min after the swinging time reaches 15 seconds, and then the roller is taken out, and the inner hole surface still has inconspicuous microcracks.

(2) The roller is hooked out by a hook and put into a 2.0% Haofton aqueous solution medium, the roller is rapidly swung back and forth in the medium at a swinging speed of about 1 m/s, the axis of the roller is ensured to be consistent with the swinging direction of the roller, so that the cooling speed of the inner hole of the roller is increased, the roller can be kept still for continuous cooling for 3min after the swinging time reaches 15 seconds, the roller can be taken out, no micro-crack on the surface of the inner hole is found, and the surface hardness is checked to reach about HRC 52.

(3) The roller is hooked out by a hook and put into a 2.5% concentration Haofton aqueous solution medium, the roller is rapidly swung back and forth in the medium at a swinging speed of about 1 m/s, the axis of the roller is ensured to be consistent with the swinging direction of the roller, so that the cooling speed of the inner hole of the roller is increased, the roller can be kept still for continuous cooling for 3min after the swinging time reaches 15 seconds, the roller can be taken out, no micro-crack on the surface of the inner hole is found, and the surface hardness is checked to reach HRC51.5 or so.

(4) The roller is hooked out by a hook and put into a 3.0% Haofton aqueous solution medium, the roller is rapidly swung back and forth in the medium at a swinging speed of about 1 m/s, the axis of the roller is ensured to be consistent with the swinging direction of the roller, so that the cooling speed of the inner hole of the roller is increased, the roller can be kept standing for continuous cooling for 3min after the swinging time reaches 15 seconds, the roller can be taken out, no micro-crack on the surface of the inner hole is found, and the surface hardness is checked to reach about HRC51. In conclusion, the concentration of the rich aqueous solution medium is 2.5 percent, and the requirement is met.

While there have been shown and described the fundamental principles and essential features of the invention and advantages thereof, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof; the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.