The corrugating roller is made by the conventional method, and the alloy steel 35CrMo is mostly used as a roller body, and then welded at both ends of the shaft head. During the production process, the heat treatment is generally performed four times, that is, after rough machining, the blank is quenched and tempered, the shaft head is relieved of stress after being welded, the intermediate frequency quenching after rough opening of the teeth, and the chrome plating after grinding the teeth.
A key process for improving the service life of corrugating rollers is chrome plating, which aims to increase the surface hardness, but there are also some disadvantages that are not easily overcome, such as thin plating (generally no more than 0.08mm) and uneven plating (thickness plating is always thicker than teeth The top, and the wear of the top of the teeth determines the service life of the corrugating roller, reduces the surface roughness of the tooth surface, and increases the cost. In particular, 2.2M or more imported adsorption assembled corrugated roller and so on. Deplating, cracking and chipping are prone to occur. Therefore, it is desirable to adopt a non-chrome plating method to increase the surface strength of the corrugating roller.
Composite heat treatment is a new process with composite functions. It is actually a method that combines several kinds of heat treatment in a proper sequence and method. That is, it has the respective technological effects of participating in the combined heat treatment process, and also has the advantages of improving the strength and resistance. Grinding and other comprehensive effects. Composite heat treatment is not a simple superposition of each process, but organically combines them according to the characteristics of a single heat treatment process, so that the advantages of each process participating in the combination are fully preserved, and the elimination effect of the ergonomics before and after the process is avoided.
First, the use of non-chrome composite heat treatment to produce corrugated roller nitriding and intermediate frequency quenching is an important composite heat treatment process, can obtain a deeper hardened layer and gentle hardness gradient, can overcome the simple nitride process high surface hardness but hard thin layer, hardness The gradient is steep and cannot withstand the disadvantages of large contact stress and impact; another advantage is that it can increase the fatigue strength of the workpiece, especially the rolling contact fatigue strength, which is of practical significance to the corrugating roller mainly subjected to the rolling fatigue movement.
In the commonly used 40Cr, 42CrMo, 35CrMo, 38CrMoA1A several kinds of nitrided steel, the best effect of nitriding is the latter. Compared with 35CrMo, 42CrMo has good comprehensive performance, high wear resistance, high hardness, and long relative service life. However, it is difficult to process, and it is prone to problems during heat treatment. If quenching does not cause defects such as cracks, it is not a problem. use less.
(1) corrugated roller body material: 42CrMo;
(2) Blank: Forging with a multi-directional forging hammer to make it evenly distributed and better eliminate the original defects;
(3) Heat treatment: In addition to conventional heat treatment, a stress-relief step is added after the heat-rolled ring segment of the corrugating roll; emphasis is placed on the compound heat treatment after the tooth roughing, and the intermediate-frequency quenching is gas ion nitriding + intermediate frequency quenching + tempering. . To change the metallographic structure of the tooth surface, promote the improvement of mechanical properties, and effectively strengthen; the nitriding process promotes the material to play the hardening potential, so that the hardness of the tooth surface can still be maintained around HPC57, thus eliminating the traditional chrome plating process, Also improves the corrugating roller finish and reduces manufacturing costs.
II. Implementation requirements In light of the problems and lessons learned from the previous practice of grinding chrome plated corrugated rollers, we believe that it was caused by two shortcomings: the lack of practical experience in formulating the plan and the inability to implement the plan seriously. So ask for:
1. An important heat treatment process is followed on site, and the progress, discovery, and problem solving are timely mastered;
2. When important mechanical processing, there should be clear regulations on the amount of knife and speed. In particular, grinding teeth should be carefully controlled to accurately control the indexing and control of the amount of feed, so as to avoid unnecessary losses, in particular to prevent the reduction of the hardness of the tooth surface.
3. The surface hardness of the corrugating roller after the manufacture is not lower than HRC56;
4. Due to the use of composite heat treatment instead of chrome plating, there is no experience. In addition to risk sharing and accidental negotiation, it also clearly stipulates quality first if there is a conflict between time and quality.
III. Acceptance At present, there is no uniform standard for the quality inspection of ion nitriding, and because the specific work and use requirements are different, the results vary greatly.
The general nitriding quality inspection is carried out on the same material sample that is carried out together with the workpiece. The anatomy is used to check the thickness, hardness, brittleness, surface state, full-phase structure, deformation and other items of the infiltration layer. However, this small quantity, high weight, and high value work for corrugating rollers cannot be used for this purpose. In addition, as the carton factory that uses the units, there is also a lack of corresponding inspection methods, which can only be based on processing inspection reports, and then tested in practice. positive. When we accepted the plant, we only focused on the following aspects:
1. Look at the appearance: normal nitrided parts should be silver gray or dark gray, there is no obvious arc burns, bruises and peeling layers.
2. Volume shape: According to the drawings carefully check whether the exposed size is out of tolerance or deformation. Make corrugated medium convex retesting and entering the factory records so that the hardness can be checked and corrected when grinding.
3. Early prevention: In the signing of the contract, taking into account the acceptance difficulties, the provisions of the appearance of qualified, but also to retain the total cost of 20%, to be paid when the corrugated roll running for a certain period of time without major problems.
Fourth, the effect 1. The first pair of rollers is expected to use a non-chrome composite heat treatment of the first pair of A-type roller, the upper and lower roller hardness reached HRC58 and HRC56.4 (the lower roller is assembled, the structure caused by the hardness lower than the upper roller) . In the unfavorable situation that more than 60% of domestic narrow-web paper (paper width less than 1.6M) and water-containing impurity rate often exceed the standard, from January 7, 1996, production of 6.5 million M2 qualified corrugated board within 14 months, corrugated The height of the paper is reduced by 0.2mm, and the diameter of the corrugating roll is reduced by less than 0.4mm. The tooth surface is never cracked or chipped.
2. Expanding the test On the basis of the initial success of the first pair of rollers, our factory once again cooperated with Kyushu to use 42CrMo as the material, and at the beginning of March of this year, we will use a non-chrome composite heat treatment process to make one- and one-type corrugating rollers. It has been extended to the entire cardboard line for comparative tests. It has been more than eight months since then and no abnormalities have been found. (waiting for new)
Excerpted from China Packaging Yearbook 1999
A key process for improving the service life of corrugating rollers is chrome plating, which aims to increase the surface hardness, but there are also some disadvantages that are not easily overcome, such as thin plating (generally no more than 0.08mm) and uneven plating (thickness plating is always thicker than teeth The top, and the wear of the top of the teeth determines the service life of the corrugating roller, reduces the surface roughness of the tooth surface, and increases the cost. In particular, 2.2M or more imported adsorption assembled corrugated roller and so on. Deplating, cracking and chipping are prone to occur. Therefore, it is desirable to adopt a non-chrome plating method to increase the surface strength of the corrugating roller.
Composite heat treatment is a new process with composite functions. It is actually a method that combines several kinds of heat treatment in a proper sequence and method. That is, it has the respective technological effects of participating in the combined heat treatment process, and also has the advantages of improving the strength and resistance. Grinding and other comprehensive effects. Composite heat treatment is not a simple superposition of each process, but organically combines them according to the characteristics of a single heat treatment process, so that the advantages of each process participating in the combination are fully preserved, and the elimination effect of the ergonomics before and after the process is avoided.
First, the use of non-chrome composite heat treatment to produce corrugated roller nitriding and intermediate frequency quenching is an important composite heat treatment process, can obtain a deeper hardened layer and gentle hardness gradient, can overcome the simple nitride process high surface hardness but hard thin layer, hardness The gradient is steep and cannot withstand the disadvantages of large contact stress and impact; another advantage is that it can increase the fatigue strength of the workpiece, especially the rolling contact fatigue strength, which is of practical significance to the corrugating roller mainly subjected to the rolling fatigue movement.
In the commonly used 40Cr, 42CrMo, 35CrMo, 38CrMoA1A several kinds of nitrided steel, the best effect of nitriding is the latter. Compared with 35CrMo, 42CrMo has good comprehensive performance, high wear resistance, high hardness, and long relative service life. However, it is difficult to process, and it is prone to problems during heat treatment. If quenching does not cause defects such as cracks, it is not a problem. use less.
(1) corrugated roller body material: 42CrMo;
(2) Blank: Forging with a multi-directional forging hammer to make it evenly distributed and better eliminate the original defects;
(3) Heat treatment: In addition to conventional heat treatment, a stress-relief step is added after the heat-rolled ring segment of the corrugating roll; emphasis is placed on the compound heat treatment after the tooth roughing, and the intermediate-frequency quenching is gas ion nitriding + intermediate frequency quenching + tempering. . To change the metallographic structure of the tooth surface, promote the improvement of mechanical properties, and effectively strengthen; the nitriding process promotes the material to play the hardening potential, so that the hardness of the tooth surface can still be maintained around HPC57, thus eliminating the traditional chrome plating process, Also improves the corrugating roller finish and reduces manufacturing costs.
II. Implementation requirements In light of the problems and lessons learned from the previous practice of grinding chrome plated corrugated rollers, we believe that it was caused by two shortcomings: the lack of practical experience in formulating the plan and the inability to implement the plan seriously. So ask for:
1. An important heat treatment process is followed on site, and the progress, discovery, and problem solving are timely mastered;
2. When important mechanical processing, there should be clear regulations on the amount of knife and speed. In particular, grinding teeth should be carefully controlled to accurately control the indexing and control of the amount of feed, so as to avoid unnecessary losses, in particular to prevent the reduction of the hardness of the tooth surface.
3. The surface hardness of the corrugating roller after the manufacture is not lower than HRC56;
4. Due to the use of composite heat treatment instead of chrome plating, there is no experience. In addition to risk sharing and accidental negotiation, it also clearly stipulates quality first if there is a conflict between time and quality.
III. Acceptance At present, there is no uniform standard for the quality inspection of ion nitriding, and because the specific work and use requirements are different, the results vary greatly.
The general nitriding quality inspection is carried out on the same material sample that is carried out together with the workpiece. The anatomy is used to check the thickness, hardness, brittleness, surface state, full-phase structure, deformation and other items of the infiltration layer. However, this small quantity, high weight, and high value work for corrugating rollers cannot be used for this purpose. In addition, as the carton factory that uses the units, there is also a lack of corresponding inspection methods, which can only be based on processing inspection reports, and then tested in practice. positive. When we accepted the plant, we only focused on the following aspects:
1. Look at the appearance: normal nitrided parts should be silver gray or dark gray, there is no obvious arc burns, bruises and peeling layers.
2. Volume shape: According to the drawings carefully check whether the exposed size is out of tolerance or deformation. Make corrugated medium convex retesting and entering the factory records so that the hardness can be checked and corrected when grinding.
3. Early prevention: In the signing of the contract, taking into account the acceptance difficulties, the provisions of the appearance of qualified, but also to retain the total cost of 20%, to be paid when the corrugated roll running for a certain period of time without major problems.
Fourth, the effect 1. The first pair of rollers is expected to use a non-chrome composite heat treatment of the first pair of A-type roller, the upper and lower roller hardness reached HRC58 and HRC56.4 (the lower roller is assembled, the structure caused by the hardness lower than the upper roller) . In the unfavorable situation that more than 60% of domestic narrow-web paper (paper width less than 1.6M) and water-containing impurity rate often exceed the standard, from January 7, 1996, production of 6.5 million M2 qualified corrugated board within 14 months, corrugated The height of the paper is reduced by 0.2mm, and the diameter of the corrugating roll is reduced by less than 0.4mm. The tooth surface is never cracked or chipped.
2. Expanding the test On the basis of the initial success of the first pair of rollers, our factory once again cooperated with Kyushu to use 42CrMo as the material, and at the beginning of March of this year, we will use a non-chrome composite heat treatment process to make one- and one-type corrugating rollers. It has been extended to the entire cardboard line for comparative tests. It has been more than eight months since then and no abnormalities have been found. (waiting for new)
Excerpted from China Packaging Yearbook 1999
Heat Press Machine,Manual Heat Press Co., Ltd. , http://www.china-presses.com