Method for strengthening cap neck of centrifugal roller

Abstract

The invention discloses a cap neck strengthening method of a centrifugal roller, which belongs to the technical field of roller manufacturing, and comprises the following steps: in the process of carrying out top pouring type core filling pouring on the core part of the roller, rushing ferromanganese powder with the particle diameter of less than 1mm into the cap neck part along with the flow, and comprising the following steps: S1, according to the use requirement of the roller, carrying out top pouring on the cap neck part of the roller; determining the content of Mn required by the cap neck part and calculating the rushing-in amount of ferromanganese powder; s2, determining the filling time of the ferromanganese powder; s3, the rushing-in flow velocity of the ferromanganese powder is determined according to calculation results of the step S1 and the step S2; and S4, when the core part pours the molten iron to the cap neck main shaft, flushing the ferromanganese powder into the molten iron along with the flow by using a funnel according to the flushing flow velocity calculated in the step S3. According to the method, the ferromanganese powder is rushed into the cap neck part along with the flow, so that the alloy content of the cap neck part is effectively increased on the premise that the alloy content of the bottom neck is not increased, the alloy content and hardness of the cap neck part of the centrifugal roller can be effectively improved, distribution of alloy elements of the cap neck part is effectively controlled, and the matrix strength of the cap neck part is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of roller manufacturing, and in particular relates to a method for strengthening the neck of a centrifugal roller. Background Art

[0002] Centrifugal rollers are key components used for rolling plates and profiles in the steel rolling industry. Their performance directly affects rolling efficiency and product quality. Traditional centrifugal rollers are usually prepared using a centrifugal casting process, in which the core is made of high-strength alloy ductile iron material to provide sufficient support and wear resistance. With the continuous advancement of rolling technology, the performance requirements for rollers are becoming increasingly higher, especially for the strength and hardness of the core ductile iron material.

[0003] In the existing centrifugal roll preparation technology, the core of the roll is usually cast by the top-filling core casting method. However, during the casting process, this method is prone to sinking due to the high density of alloy elements, resulting in a relatively low alloy content at the neck of the roll, which makes the hardness of the neck of the roll relatively low. This uneven hardness seriously affects the overall performance and service life of the roll, especially in a rolling environment that is subjected to high loads and frequent impacts.

[0004] Therefore, a method for strengthening the neck of a centrifugal roll which can increase the alloy content and hardness of the neck is now needed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for strengthening the neck of a centrifugal roller, which can effectively improve the alloy content and hardness of the neck of the centrifugal roller, effectively control the distribution of alloy elements in the neck and improve the matrix strength of the neck.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A method for strengthening the neck of a centrifugal roller comprises the following steps: during top-filling core pouring of the roller core, ferromanganese powder with a particle diameter of less than 1 mm is injected into the neck of the roller core.

[0008] Step S1: According to the use requirements of the roll, determine the Mn content required for the necking position and calculate the amount of ferromanganese powder injected. The calculation formula is as follows:

[0009]

[0010] In the formula, the Mn recovery rate of the core part of the cap is 95%;

[0011] Step S2: Determine the injection time of ferromanganese powder, and the calculation formula is as follows:

[0012]

[0013] Step S3: Determine the inflow velocity of ferromanganese powder according to the calculation results of step S1 and step S2, and the calculation formula is as follows:

[0014]

[0015] Step S4: When the core is poured with molten iron up to the main shaft of the neck, the ferromanganese powder is flushed into the molten iron using a funnel according to the flushing flow rate calculated in step S3.

[0016] A further improvement of the technical solution of the present invention is that in step S1, the Mn content required for the burr neck is 0.9%.

[0017] A further improvement of the technical solution of the present invention is that in step S4, the funnel adopts a flow-following inoculation funnel, and the flow-following inoculation funnel adjusts the opening size at the bottom of the funnel through the flow rate baffle equipped with it to control the real-time flow rate of the ferromanganese powder to be consistent with the ferromanganese powder injection flow rate calculated in step S3.

[0018] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0019] The neck strengthening method of the centrifugal roller of the present invention effectively increases the alloy content of the neck without increasing the alloy content of the bottom neck by flushing ferromanganese powder into the neck position of the centrifugal roller. The alloy content and hardness of the neck position of the centrifugal roller can be effectively improved, the distribution of alloy elements in the neck position of the centrifugal roller can be effectively controlled, and the matrix strength of the neck position of the centrifugal roller can be improved.

[0020] The ferromanganese powder used in the present invention has a melting point lower than the core casting temperature and can be quickly melted and evenly distributed in molten iron without causing a significant increase in the amount of carbides.

[0021] The present invention injects Mn element into the roll neck during pouring. The addition of Mn element enhances the matrix strength of molten iron through solid solution strengthening, thereby strengthening the roll neck matrix, changing the ratio of ferrite and pearlite content in the casting, increasing the pearlite content and reducing the ferrite amount, and can effectively improve the strength and hardness of the roll neck. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with embodiments:

[0023] The present invention provides a method for strengthening the neck of a centrifugal roller. During top-filling core casting of the roller core, ferromanganese powder with a particle diameter of less than 1 mm is injected into the neck of the roller. The method comprises the following steps:

[0024] Step S1: According to the use requirements of the roll, determine the Mn content required for the necking position and calculate the amount of ferromanganese powder injected. The calculation formula is as follows:

[0025]

[0026] In the formula, the Mn recovery rate of the core part of the cap is 95%;

[0027] Among them, the Mn content required for the neck of the cap is 0.9%;

[0028] Step S2: Determine the injection time of ferromanganese powder, and the calculation formula is as follows:

[0029]

[0030] Step S3: Determine the inflow velocity of ferromanganese powder according to the calculation results of step S1 and step S2, and the calculation formula is as follows:

[0031]

[0032] Step S4: When the core is poured with molten iron to the main shaft of the neck, the ferromanganese powder is flushed into the molten iron with the funnel according to the flushing flow rate calculated in step S3, wherein the funnel can be a flow-following inoculation funnel, and the flow-following inoculation funnel adjusts the opening size at the bottom of the funnel through the flow rate baffle equipped with it to control the real-time flow rate of the ferromanganese powder to be consistent with the flow rate of the ferromanganese powder calculated in step S3, that is, before the ferromanganese powder is flushed into the molten iron, the opening size at the bottom of the funnel can be adjusted by adjusting the flow rate baffle, and then the real-time flow rate of the ferromanganese powder is calculated by using a flow meter or calculating the total mass of the ferromanganese powder passing through the funnel and the required time, and then the flow rate baffle is continuously adjusted until the real-time flow rate of the ferromanganese powder is consistent with the flow rate of the ferromanganese powder calculated in step S3. The funnel can also be a remote-controlled flow-following inoculation funnel, and the real-time flow rate of the ferromanganese powder can be controlled by remote control.

[0033] The following is an example of the centrifugal work roll used for hot rolling rough rolling to verify the neck strengthening method of the centrifugal roll:

[0034] When the centrifugal working roll is not flushed with ferromanganese powder, the Mn content of the finished product neck is detected to be 0.3-0.4%, and the neck hardness is 34-36HSD. The neck strengthening method of the centrifugal roll is used. During the top-filling core pouring process of the core of the roll, ferromanganese powder with a particle diameter of less than 1mm is flushed with the flow at the neck of the roll. The specific operation steps are as follows:

[0035] Step S1: According to the use requirements of the centrifugal working roll, the Mn content required for the neck portion is determined and the amount of ferromanganese powder injected is calculated. The calculation formula is as follows:

[0036]

[0037] Wherein, the target Mn content of the core of the centrifugal roller neck is 0.9%, the existing Mn content of the core of the neck is 0.3%-0.4%, the Mn recovery rate of the core of the neck is 95%, the Mn content of the ferromanganese powder is 65%, the amount of molten iron in the spindle of the neck is 0.85t, and the amount of ferromanganese powder injected is determined to be 8.28kg according to the above formula;

[0038] Step S2: Determine the injection time of ferromanganese powder, and the calculation formula is as follows:

[0039]

[0040] In the formula, the amount of molten iron in the main shaft of the neck is 0.85t, and the pouring speed is 0.7t / min. According to the above formula, the time for ferromanganese powder to be injected is about 1.2min;

[0041] Step S3: Determine the inflow velocity of ferromanganese powder according to the calculation results of step S1 and step S2, and the calculation formula is as follows:

[0042]

[0043] In the formula, the amount of ferromanganese powder injected is 8.28kg, and the time of ferromanganese powder injected is about 1.2min. According to the above formula, the injection flow rate of ferromanganese powder is determined to be 6.9kg / min;

[0044] Step S4: When the core is poured with molten iron to the main shaft of the burr neck, the ferromanganese powder is flushed into the molten iron using a funnel according to the flushing flow rate of 6.9 kg / min calculated in step S3. The funnel adopts a flow-following inoculation funnel. The flow-following inoculation funnel adjusts the opening size at the bottom of the funnel through the flow rate baffle it is equipped with to control the real-time flow rate of the ferromanganese powder to be consistent with the ferromanganese powder flushing flow rate calculated in step S3.

[0045] After the above treatment, the Mn content of the finished product neck is detected to be 0.8-0.9%, the neck hardness is 39-42HSD, and the bottom neck hardness is not significantly increased. It can be seen that the neck strengthening method of the centrifugal roller of the present invention effectively increases the neck alloy content without increasing the bottom neck alloy content by flushing ferromanganese powder into the neck position of the centrifugal roller, and can effectively improve the alloy content and hardness of the neck position of the centrifugal roller, effectively control the distribution of alloy elements in the neck position of the centrifugal roller, and improve the matrix strength of the neck position of the centrifugal roller.

[0046] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for strengthening the neck of a centrifugal roller, characterized in that: During the top-filling core pouring process of the roll core, ferromanganese powder with a particle diameter of less than 1 mm is injected into the neck of the roll core, including the following steps: Step S1: According to the use requirements of the roll, determine the Mn content required for the necking position and calculate the amount of ferromanganese powder injected. The calculation formula is as follows: In the formula, the Mn recovery rate of the core part of the cap is 95%; Step S2: Determine the injection time of ferromanganese powder, and the calculation formula is as follows: Step S3: Determine the inflow velocity of ferromanganese powder according to the calculation results of step S1 and step S2, and the calculation formula is as follows: Step S4: When the core is poured with molten iron up to the main shaft of the neck, the ferromanganese powder is flushed into the molten iron using a funnel according to the flushing flow rate calculated in step S3.

2. A method for strengthening the neck of a centrifugal roller according to claim 1, characterized in that: In step S1, the Mn content required for the burr neck is 0.9%.

3. The method for strengthening the neck of a centrifugal roller according to claim 2, characterized in that: In step S4, the funnel is a flow-following inoculation funnel, and the flow-following inoculation funnel adjusts the opening size at the bottom of the funnel through the flow rate baffle equipped therewith to control the real-time flow rate of the ferromanganese powder to be consistent with the ferromanganese powder injection flow rate calculated in step S3.

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