Method for improving plasticity of tin-based babbitt alloy

Abstract

The invention discloses a method for improving plasticity of tin-based babbitt metal, and belongs to the technical field of material science. The preparation method of the high-plasticity tin-based babbitt alloy comprises the following steps that the tin-based babbitt alloy is melted, and then degassing, deslagging, standing and homogenizing are conducted; performing ultrasonic vibration treatment to obtain semi-solid slurry; the semi-solid slurry is poured into a mold and rapidly subjected to water cooling, and a tin-based babbitt metal semi-solid blank is obtained; wherein the ultrasonic termination temperature is between 240 DEG C and 280 DEG C. According to the method, the final temperature of ultrasonic vibration treatment of the tin-based babbitt metal is controlled, so that the SnSb phase morphology is converted into fine regular square crystals from thick rose-shaped crystals or petal-shaped crystals, and the plasticity of the tin-based babbitt metal is improved. The method is simple in process, low in cost and easy to control, industrialization is easy to achieve, and good application prospects are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of tin-based alloys, and in particular relates to a method for improving the plasticity of a tin-based babbitt alloy. Background Art

[0002] Tin-based Babbitt alloy has good wear resistance, good plasticity, excellent running-in, embedding and anti-seizure properties, good heat resistance and corrosion resistance. It is suitable for manufacturing bearings, bushings and sleeves that withstand high speeds, high pressures and impact loads. It is recognized as the preferred material for bearings.

[0003] In the traditional forming method, the Cu6Sn5 phase in the tin-based babbitt alloy is in the shape of an elongated needle, and the precipitation temperature of the SnSb phase is 100°C lower than the liquidus. During the solidification process, the solute gathers at the solidification front, and there is an uneven distribution and gradient distribution of the solute elements. After the SnSb phase precipitates, it tends to preferentially grow into rose-shaped crystals or petal-shaped crystals; there is stress concentration at the tips of the Cu6Sn5 phase and the SnSb phase. During service, the tips can easily become crack sources and cause crack initiation, which cuts the matrix and causes the parts to fail, causing brittle fracture of the parts, thus greatly limiting the application range of the tin-based babbitt alloy.

[0004] In order to improve the plasticity of tin-based babbitt alloy, the plasticity of the alloy is currently improved mainly by adding elements; for example, by adding 0.83wt% Zn to SnSb8Cu4 alloy, Zn reduces the solid solubility of Sb element in the matrix, precipitates more SnSb phase at the grain boundary, improves the plasticity of the alloy, but reduces the strength of the alloy; therefore, the development of high-plasticity tin-based babbitt alloy has great industrial application significance. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for improving the plasticity of a tin-based babbitt alloy, by controlling the process to prepare a fine SnSb phase microstructure with a regular square morphology, thereby improving the plasticity of the tin-based babbitt alloy. To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for improving the plasticity of tin-based babbitt alloy comprises the following steps:

[0007] (1) The tin-based babbitt alloy is melted, then degassed and deslaged and allowed to stand for homogenization.

[0008] (2) The homogenized molten metal is subjected to ultrasonic vibration treatment, and the termination temperature of the ultrasonic vibration treatment is lower than 280° C., thereby obtaining a semi-solid slurry of tin-based babbitt alloy.

[0009] (3) The semi-solid slurry of the tin-based babbitt alloy is poured into a mold and rapidly water-cooled to obtain a high-plasticity tin-based babbitt alloy.

[0010] As the optimal implementation parameter of the present invention, in the step (1), the melting temperature of the tin-based babbitt alloy is 500°C to 550°C.

[0011] As the optimal implementation parameter of the present invention, in the step (1), after the tin-based babbitt alloy is smelted, the temperature of the alloy melt is reduced to 500° C. to 550° C. and then degassing and deslagging treatment is carried out.

[0012] As the optimal implementation parameter of the present invention, in the step (1), after the tin-based babbitt alloy is degassed and deslaged, it is kept warm for 10 to 15 minutes.

[0013] As the optimal implementation parameters of the present invention, in step (2), the ultrasonic termination temperature is 240°C to 280°C, the ultrasonic starting temperature is 370°C to 400°C, and the ultrasonic power is 1000W to 1500W.

[0014] Through a large number of experimental studies, it is found that the high-plasticity tin-based babbitt alloy can be prepared only when the ultrasonic termination temperature of the present invention is 240°C to 280°C.

[0015] As the optimal implementation parameters of the present invention, in step (3), the mold temperature is 40°C to 100°C, and the water temperature during water cooling is 20°C to 30°C.

[0016] As the optimal implementation parameter of the present invention, in the step (1), ultrasonic treatment is started after the temperature of the tin-based babbitt alloy drops to 370°C to 400°C, and the front end of the ultrasonic horn is preheated to 370°C to 400°C.

[0017] The present invention also claims to protect the high-plasticity tin-based babbitt alloy prepared by the high-plasticity tin-based babbitt alloy preparation method.

[0018] Cu6Sn5 phase is the first precipitation phase, and it begins to precipitate when the melt temperature is lower than the liquidus line. The Cu6Sn5 phase microstructure can be refined to a certain extent by controlling the cooling rate. However, the precipitation temperature of the SnSb phase is 100°C lower than the liquidus line, and the traditional forming method cannot control its growth into coarse rose-shaped crystals or petal-shaped crystals. In particular, the plasticity of the tin-based babbitt alloy is determined by the SnSb phase, which has a serious negative impact on the plasticity of the alloy. The present invention solves this problem in two directions. First, ultrasonic vibration processing technology is used to produce SnSb phase in the melt. The cavitation effect and acoustic streaming effect are generated, and the instantaneous bursting of bubbles produces extreme supercooling, which promotes grain nucleation and grain refinement. The acoustic streaming effect can make the temperature field and solute field inside the melt more uniform, and suppress the anisotropy of the grains; the second is to control the termination temperature of ultrasonic vibration, which is 20 to 30 °C above the precipitation of SnSb phase, providing kinetic conditions for the precipitation of SnSb phase; through the coordinated regulation of ultrasonic vibration processing technology and termination temperature, a high-plasticity tin-based babbitt alloy with a fine SnSb phase microstructure with regular square morphology is prepared.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) Aiming at the requirement of high plasticity of tin-based babbitt alloy, the present invention is different from the existing technology of adding alloy elements to improve the plasticity of alloy. Instead, it is the first time to use the traditional casting method to combine ultrasonic vibration technology with low pouring temperature technology to synergistically control the microstructure of the alloy to prepare high-plasticity tin-based babbitt alloy without reducing the strength of the alloy. The present invention provides the necessary microstructure and performance requirements for the expansion of tin-based babbitt alloy into fields such as alloy wire preparation.

[0021] (2) The device of the present invention has a simple structure, low cost, high efficiency, can continuously prepare semi-solid slurry, and can be combined with existing forming equipment such as extrusion and die casting to directly obtain formed parts under pressure, which is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a method for preparing the high-plasticity tin-based babbitt alloy of the present invention;

[0023] Figure 2 is a microstructure diagram of a high-plasticity tin-based babbitt alloy prepared in Example 1 without applying ultrasonic vibration treatment;

[0024] Figure 3 This is a microstructure diagram of a high-plasticity tin-based babbitt alloy prepared by applying ultrasonic vibration treatment in Example 2 at a termination temperature of 240°C;

[0025] Figure 4 This is a microstructure diagram of a high-plasticity tin-based babbitt alloy prepared by applying ultrasonic vibration treatment at a termination temperature of 250° C. in Example 3;

[0026] Figure 5 This is a microstructure diagram of a high-plasticity tin-based babbitt alloy prepared by applying ultrasonic vibration treatment at a termination temperature of 260° C. in Example 4;

[0027] Figure 6 This is a microstructure diagram of a high-plasticity tin-based babbitt alloy prepared by applying ultrasonic vibration treatment at a termination temperature of 270° C. in Example 5;

[0028] Figure 7 1 is the stress-strain curve of the high-plasticity tin-based babbitt alloy prepared in Examples 1 to 5. DETAILED DESCRIPTION

[0029] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods, but the protection scope of the present invention is not limited to the described contents.

[0030] Example 1

[0031] A method for preparing a high-plasticity tin-based babbitt alloy specifically comprises the following steps:

[0032] (1) Weigh 2 kg of SnSbCu11-6 alloy block, heat and melt it in a medium frequency induction furnace at a melting temperature of 550°C, then degas and deslag and let it stand for 12 minutes for homogenization.

[0033] (2) When the melt temperature of the SnSbCu11-6 alloy drops to 390°C, ultrasonic vibration treatment is applied with an ultrasonic power of 1000 W until the melt temperature drops to 240°C and then the ultrasonic vibration treatment is stopped.

[0034] (3) The semi-solid slurry of SnSbCu11-6 alloy was poured into a mold preheated to 80°C and quickly water-cooled to obtain a semi-solid billet.

[0035] from Figure 3 It can be found that the SnSb phase morphology in the tin-based babbitt alloy prepared in this embodiment is transformed into a regular square shape. Compared with Comparative Example 1, the strength remains basically unchanged, but the plasticity is improved.

[0036] Example 3

[0037] A method for preparing a high-plasticity tin-based babbitt alloy specifically comprises the following steps:

[0038] (1) Weigh 2 kg of SnSbCu11-6 alloy block, heat and melt it in a medium frequency induction furnace at a melting temperature of 540°C, then degas and deslag and let it stand for 15 minutes for homogenization.

[0039] (2) When the melt temperature of the SnSbCu11-6 alloy drops to 390°C, ultrasonic vibration treatment is applied with an ultrasonic power of 1200 W until the melt temperature drops to 250°C, then the ultrasonic vibration treatment is stopped.

[0040] (3) The semi-solid slurry of SnSbCu11-6 alloy was poured into a mold preheated to 60°C and quickly water-cooled to obtain a semi-solid billet.

[0041] from Figure 4 It can be found that when the termination temperature of ultrasonic vibration treatment is 250℃, the size ratio Figure 2 The particles are smaller and have more regular morphology, which is further beneficial to improving the plasticity of the alloy. Compared with Comparative Example 1, the strength remains basically unchanged, but the plasticity is improved.

[0042] Example 4

[0043] A method for preparing a high-plasticity tin-based babbitt alloy specifically comprises the following steps:

[0044] (1) Weigh 2 kg of SnSbCu11-6 alloy block, heat and melt it in a medium frequency induction furnace at a melting temperature of 550°C, then degas and deslag and stand it for 15 minutes for homogenization.

[0045] (2) When the melt temperature of the SnSbCu11-6 alloy drops to 390°C, ultrasonic vibration treatment is applied with an ultrasonic power of 1200 W until the melt temperature drops to 260°C and then the ultrasonic vibration treatment is stopped.

[0046] (3) The semi-solid slurry of SnSbCu11-6 alloy was poured into a mold preheated to 50°C and quickly water-cooled to obtain a semi-solid billet.

[0047] from Figure 5 It can be found that when the termination temperature of ultrasonic vibration treatment is 260℃, the equivalent size of Cu6Sn5 phase and SnSb phase is the smallest and the morphology is more regular. Size refinement is conducive to improving the deformation synergy of the alloy and maximizing the plasticity of the alloy. At this time, the plasticity is the best, such as Figure 7 As shown, compared with Comparative Example 1, the strength remains basically unchanged, but the plasticity is improved.

[0048] Example 5

[0049] A method for preparing a high-plasticity tin-based babbitt alloy specifically comprises the following steps:

[0050] (1) Weigh 2 kg of SnSbCu11-6 alloy block, heat and melt it in a medium frequency induction furnace at a melting temperature of 530°C, then degas and deslag and stand it for 13 minutes for homogenization.

[0051] (2) When the melt temperature of the SnSbCu11-6 alloy drops to 370°C, ultrasonic vibration treatment is applied with an ultrasonic power of 1000 W until the melt temperature drops to 280°C and then the ultrasonic vibration treatment is stopped.

[0052] (3) The semi-solid slurry of SnSbCu11-6 alloy was poured into a mold preheated to 50°C and quickly water-cooled to obtain a semi-solid billet.

[0053] from Figure 6 It can be seen that Figure 5 In comparison, when the termination temperature of ultrasonic vibration treatment is 280℃, the Cu6Sn5 phase and SnSb phase begin to coarsen again, especially the coarsening of SnSb phase is more obvious, which will damage the plasticity of the alloy.

[0054] Depend on Figure 7It can be seen that applying ultrasonic vibration treatment according to the method of the present invention can significantly improve the plasticity of SnSbCu11-6 alloy, and reasonable process parameters can obtain optimal mechanical properties. Under the optimal process parameters, the plasticity after ultrasonic treatment is improved by 113% compared with the plasticity without ultrasonic treatment.

[0055] Comparative Example 1

[0056] A method for preparing tin-based babbitt alloy is specifically as follows:

[0057] (1) Weigh 2 kg of SnSbCu11-6 alloy block, heat and melt it in a medium frequency induction furnace at a melting temperature of 550°C, then degas and deslag and stand it for 15 minutes for homogenization.

[0058] (2) The SnSbCu11-6 alloy melt was directly poured into a mold preheated to 50°C and rapidly water-cooled to obtain a conventional alloy billet.

[0059] from Figure 2 It can be found that the microstructure of conventional casting is coarse, the Cu6Sn5 phase is slender needle-shaped, and the SnSb phase is rose crystal or petal-shaped, which can easily split the matrix and reduce the plasticity of the alloy.

Claims

1. A method for improving the plasticity of tin-based babbitt alloy, characterized in that: The process of preparing a fine SnSb phase microstructure with a regular square morphology is controlled to improve the plasticity of the tin-based babbitt alloy, which specifically includes the following steps: (1) melting the tin-based babbitt alloy, then degassing and deslagging it and standing it for homogenization; (2) subjecting the homogenized metal liquid to ultrasonic vibration treatment to obtain a tin-based babbitt alloy semi-solid slurry; (3) pouring the semi-solid slurry of tin-based babbitt alloy into a mold and rapidly cooling it with water to obtain a high-plasticity tin-based babbitt alloy; in the step (2), the termination temperature of the ultrasonic vibration treatment is lower than 280°C.

2. The method for preparing the high-plasticity tin-based babbitt alloy according to claim 1, characterized in that: In the step (1), the melting temperature of the tin-based babbitt alloy is 500°C to 550°C.

3. The method for preparing the high-plasticity tin-based babbitt alloy according to claim 1, characterized in that: In the step (1), after the tin-based babbitt alloy is smelted, the temperature of the alloy melt is lowered to 500° C. to 550° C. and then degassing and deslagging treatment is performed.

4. The method for preparing the high-plasticity tin-based babbitt alloy according to claim 1, characterized in that: In the step (1), after the tin-based babbitt alloy is degassed and deslaged, it is kept warm for 10 to 15 minutes.

5. The method for preparing the high-plasticity tin-based babbitt alloy according to claim 1, characterized in that: In the step (1), ultrasonic treatment is started after the temperature of the tin-based babbitt alloy drops to 370°C to 400°C, and the front end of the ultrasonic horn is preheated to 370°C to 400°C.

6. The method for preparing the high-plasticity tin-based babbitt alloy according to claim 1, characterized in that: In the step (2), the ultrasonic starting temperature is 370°C to 400°C, the ultrasonic ending temperature is 240°C to 280°C, and the ultrasonic power is 1000W to 1500W.

7. The method for preparing the high-plasticity tin-based babbitt alloy according to claim 1, characterized in that: In the step (3), the mold temperature is 40°C to 100°C, and the water temperature during water cooling is 20°C to 30°C.

8. A high-plasticity tin-based babbitt alloy prepared according to the method for preparing a high-plasticity tin-based babbitt alloy according to any one of claims 1 to 7.

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