Effect of Forging Temperature on Wear Resistance of Stainless Steel Flange
304 stainless steel flange was forged at different forging temperatures, and the wear properties at 25 ℃ and 500 ℃ were tested and analyzed. The results show that when the initial forging temperature is increased from 1100 ℃ to 1190 ℃, and the final forging temperature is increased from 760 ℃ to 880 ℃, the room temperature wear resistance of flanges is improved first, then basically unchanged, and then decreased, while the high-temperature wear resistance is improved first, and then decreased; The initial forging temperature and final forging temperature of the 304 stainless steel flanges are preferably 1145 ℃ and 860 ℃ respectively.
Stainless steel flange is a commonly used component, which has been widely used in various fields, and has attracted more researchers’ attention. Wang Yinwei [1,2] optimized the forging temperature of 304 stainless steel flange based on dynamic recrystallization, and simulated the evolution of its forging microstructure. Jing Weihai et al. [3] studied the welding method and process of stainless steel flange and copper pipe. Lu Yueyang et al. [4] studied the upsetting extrusion process of austenitic stainless steel flanges. Deng Xiangzhong [5] studied and analyzed the flange structure of stainless steel shell and tube heat exchanger. Fan Xiuqian [6] studied the investment casting technology of stainless steel flange elbow. Wang Jianyong et al. [7] studied the welding process of porous stainless steel pipe and dense flange. Wear resistance is an important performance of stainless steel flanges. With the improvement of the market requirements for stainless steel flanges, the research on wear resistance of stainless steel flanges is very important, especially at room temperature and high temperature. Forging is the main forming process of stainless steel flange, and forging temperature is the most important forging process parameter. However, the research on the effect of forging temperature on the wear performance of stainless steel flange is still less, which is difficult to meet the needs of large-scale industrial production. Therefore, the author used different forging temperatures to conduct forging tests on stainless steel flanges, tested and analyzed the wear properties of stainless steel flanges at 25 ℃ room temperature and 500 ℃ high temperature, and studied the influence of forging temperatures on the wear properties of stainless steel flanges at room temperature and high temperature.
1. Test
Table of Contents
1.1 Materials
The test material is forged 304 stainless steel flange, as shown in Figure 1. The chemical composition of the flange is shown in Table 1. The forging test of 304 stainless steel flange is carried out on a 1500t forging press. The specific forging process parameters of 304 stainless steel flange are shown in Table 2. During the forging process, keep the die preheating temperature (330 ℃) and forging speed (10mm/s) unchanged, and change the initial forging temperature and final forging temperature.
Figure.1 Forged stainless steel flange and its test sampling position
Table.1 Chemical composition of flange
| Component | Mass fraction 1% | Component | Mass fraction 1% |
| C | ≤0.08 | Ni | 8.000-11.000 |
| Mn | ≤2.00 | S | ≤0.030 |
| Si | ≤1.00 | P | ≤0.045 |
| Cr | 18.00-20.00 |
Table.2. Forging process of flange
| Serial number | Initial forging temperature/℃ | Final forging temperature/℃ | Mold preheating temperature/℃ | Forging speed/(mm. s-1) |
| 1# | 1100 | 860 | 330 | 10 |
| 2# | 1130 | 860 | 330 | 10 |
| 3# | 1145 | 860 | 330 | 10 |
| 4# | 1160 | 860 | 330 | 10 |
| 5# | 1190 | 860 | 330 | 10 |
| 6# | 1145 | 760 | 330 | 10 |
| 7# | 1145 | 800 | 330 | 10 |
| 8# | 1145 | 840 | 330 | 10 |
| 9# | 1145 | 880 | 330 | 10 |
1.2 Methods
Cut the room temperature and high temperature wear test samples on the forged 304 stainless steel flange with wire cutting according to the position shown in Figure 1. The sample is in round sheet shape, with a diameter of 25mm and a thickness of 10mm. The wear test was carried out on THT high and low temperature wear tester at 25 ℃ room temperature and 500 ℃ high temperature. The wear volume was recorded, and the worn surface morphology of the specimen was observed with EVO18 scanning electron microscope (SEM). During the wear test, set the speed of the grinding wheel to 300r/min, the wear time to 15min, the relative sliding speed to 90mm/min, and the load to 100N, and select the test piece body for the grinding material. During the wear test, the larger the wear volume is, the worse the wear performance of the specimen is; On the contrary, the smaller the wear volume is, the better the time wear performance is. The arithmetic mean of the wear volume test values of the three parallel test pieces is taken as the wear volume test value of the flange sample.
2. Results and Analysis
2.1 Room temperature wear performance
During the forging test, when the final forging temperature is 860 ℃, the die preheating temperature is 330 ℃ and the forging speed is 10mm/s, the wear performance test results of 304 stainless steel flange formed by forging at 25 ℃ room temperature when the initial forging temperature is changed are shown in Figure 2. It can be seen that the initial forging temperature has an impact on the room temperature wear properties of flanges. When the initial forging temperature gradually increases from 1100 ℃ to 1190 ℃, the room temperature wear volume of flange first decreases, then basically remains unchanged, and then increases. The room temperature wear property of flange first improves, then remains unchanged, and then decreases. When the initial forging temperature is 1100 ℃, the maximum wear volume of flange at room temperature is 30.7 × 10-3mm3; When the initial forging temperature is increased to 1130-1160 ℃, the wear volume of flange at room temperature decreases significantly, about 20 × 10-3mm3; If the initial forging temperature is further increased to 1190 ℃, the wear volume of flange at room temperature will increase to 24.3 instead of decreasing × 10-3mm3. It can be seen that when the initial forging temperature is 1130-1160 ℃, the forged 304 stainless steel flange has better room temperature wear resistance.
When the final forging temperature is 860 ℃, the die preheating temperature is 330 ℃ and the forging speed is 10mm/s, the room temperature wear surface morphology of 304 stainless steel flange formed by forging at different initial forging temperatures is shown in Figure 3. It can be seen from Fig. 3a that when the initial forging temperature is 1100 ℃, there are many wrinkles, peeling or falling off on the surface of the flange after the wear test, and the wear phenomenon is relatively serious. It can be seen from Fig. 3b that when the initial forging temperature is 1145 ℃, there is no obvious wrinkle, peeling or falling off on the surface of the flange after the wear test, and the wear phenomenon is significantly reduced compared with that when the initial forging temperature is 1100 ℃, showing better room temperature wear performance. This is consistent with the flange room temperature wear volume test data.
Under the condition that the initial forging temperature is 1145 ℃, the die preheating temperature is 330 ℃ and the forging speed is 10mm/s, the wear performance test results of 304 stainless steel flange forged at 25 ℃ room temperature when the final forging temperature is changed are shown in Figure 4. It can be seen that the final forging temperature has an impact on the wear resistance of flanges at room temperature. When the final forging temperature gradually increases from 760 ℃ to 880 ℃, the room temperature wear volume of the flange first decreases, then basically remains unchanged, and then increases. The room temperature wear performance of the flange first improves, then remains unchanged, and then decreases. When the final forging temperature is 760 ℃, the maximum wear volume of flange at room temperature is 28.7 × 10-3mm3; When the final forging temperature is increased to 840-860 ℃, the wear volume of flange at room temperature decreases significantly, about 20 × 10-3mm3; If the final forging temperature is further increased to 880 ℃, the wear volume of flange at room temperature will increase to 24.9 instead of decreasing × 10-3mm3. It can be seen that when the final forging temperature is 840-860 ℃, the forged 304 stainless steel flange has better room temperature wear resistance.
Figure.2 Effect of initial forging temperature on flange wear performance
Figure.3 Surface morphology of forged flanges at different temperatures after abrasion at room temperature
Figure.4 Effect of final forging temperature on flange wear performance
2.2 High temperature wear performance
During the forging test, when the final forging temperature is 860 ℃, the die preheating temperature is 330 ℃ and the forging speed is 10mm/s, the wear performance test results of 304 stainless steel flange formed by forging at 500 ℃ when the initial forging temperature is changed are shown in Figure 5. It can be seen that the initial forging temperature has a significant impact on the high-temperature wear performance of the flange. When the initial forging temperature increases from 1100 ℃ to 1190 ℃, the high temperature wear volume of flange decreases first and then increases, and the high temperature wear property of flange increases first and then decreases. When the initial forging temperature is 1100 ℃, the high temperature wear volume of flange is the largest, up to 53.8 × 10-3mm3; When the initial forging temperature is increased to 1145 ℃, the wear volume of flange at room temperature is the minimum (29.6 × 10-3mm3), which is 45% less than that when forging at 1100 ℃; If the initial forging temperature is further increased to 1190 ℃, the wear volume of flange at room temperature will increase rather than decrease. It can be seen that when the initial forging temperature is 1145 ℃, the forged 304 stainless steel flange has the best high-temperature wear resistance. In order to improve the wear resistance at high temperature, the initial forging temperature of 304 stainless steel flange formed by forging is 1145 ℃.
Figure.5 Effect of initial forging temperature on flange wear performance
Under the condition that the initial forging temperature is 1145 ℃, the die preheating temperature is 330 ℃ and the forging speed is 10mm/s, the wear performance test results of 304 stainless steel flange forged at 500 ℃ when the final forging temperature is changed are shown in Figure 6. It can be seen that the final forging temperature has an impact on the high-temperature wear performance of the flange. When the final forging temperature increases from 760 ℃ to 880 ℃, the high temperature wear volume of the flange decreases first and then increases, and the high temperature wear property of the flange increases first and then decreases. When the final forging temperature is 760 ℃, the high temperature wear volume of flange is the largest, up to 52.4 × 10-3mm3; When the final forging temperature is increased to 860 ℃, the high temperature wear volume of flange is the minimum (29.6 × 10-3mm3), 44% less than that of final forging at 760 ℃; If the final forging temperature is further increased to 880 ℃, the high temperature wear volume of flange will increase to 38.4 instead of decreasing × 10-3mm3. It can be seen that when the final forging temperature is 860 ℃, the forged 304 stainless steel flange has the best high-temperature wear resistance. In order to improve the wear resistance at high temperature, the final forging temperature of 304 stainless steel flange is 860 ℃.
Figure.6 Effect of final forging temperature on flange wear performance
When the initial forging temperature is 1145 ℃, the die preheating temperature is 330 ℃ and the forging speed is 10mm/s, the high-temperature wear surface morphology of 304 stainless steel flange formed by forging at different final forging temperatures is shown in Figure 7. It can be seen from Fig. 7a that when the final forging temperature is 760 ℃, the surface of the flange is full of wrinkles, peeling or falling off after the wear test, and the wear phenomenon is extremely serious. It can be seen from Fig. 7b that when the final forging temperature is 860 ℃, after the flange wear test, there are only small wear marks and a small number of small pits on the surface, without obvious wrinkles or peeling, and the wear phenomenon is significantly reduced compared with that when forging at 1100 ℃, showing better room temperature wear performance. It can be seen from Fig. 7c that when the final forging temperature is 860 ℃, the surface wear morphology after the flange wear test is between 760 ℃ final forging and 860 ℃ final forging. This is consistent with the flange room temperature wear volume test data.
Figure.7 Surface morphology of final forged flanges at different temperatures after abrasion at room temperature
2.3 Discussion and analysis
In the forging process of 304 stainless steel flange, the initial forging temperature and final forging temperature are two extremely important forging process parameters. If the initial forging temperature of 304 stainless steel flange is 1100 ℃ lower or the final forging temperature is 760 ℃ lower, it will be difficult to provide enough heat to the inside of the flange, resulting in reduced plasticity, greater deformation resistance, and it is very easy to produce cold work hardness, resulting in microcracks and other defects in flange forgings, thus reducing the wear resistance of the flange. Properly increasing the initial forging temperature and final forging temperature will help to increase the internal heat of the flange, thereby improving its plasticity, reducing deformation resistance, reducing the generation of defects, so as to obtain high-quality flange forgings and improve the wear resistance of the flange. However, if too high initial forging temperature (1190 ℃) or too high final forging temperature (880 ℃) is selected, the excess energy inside the flange will lead to grain coarsening, even flange overburning, resulting in changes in flange material, size, etc. It is difficult to obtain high-quality flange forgings, leading to a decline in the wear resistance of the flange. This is why the initial forging temperature and final forging temperature of 304 stainless steel flange should not be too low or too high, and 1145 ℃ and 860 ℃ are preferred respectively.
The wear of 304 stainless steel flange forgings mainly goes through three stages: initial wear, stable wear and accelerated wear. In the initial wear stage, under the action of external load, the flange surface in contact with the grinding wheel appears high stress sliding. When the low or high initial forging temperature or final forging temperature is selected, due to the existence of cracks and other internal defects, the flange is difficult to resist this high stress sliding, so deep wear marks appear on the flange surface, and the wear resistance of the flange is poor; When selecting the appropriate initial forging temperature and final forging temperature, high-quality flanges can significantly improve the ability to resist such high stress sliding, so that the wear marks on the flange surface become significantly thinner and shallower, and the flange has better wear resistance. In the stable wear stage, with the repeated friction and wear, the original wear marks will continue to deepen. On the basis of the deepening of wear marks, flanges with poor resistance to friction and wear may even have wrinkles, peeling or falling off; However, the wear marks of flanges with good wear resistance are only deepened to a limited extent, and there are often no obvious wrinkles, peeling or falling off. In the accelerated wear stage, in the further friction and wear process, the wear of flanges with poor wear resistance deteriorates more significantly, with more wrinkles, peeling or falling off on the surface, and the wear marks become more coarse; The flange with good wear resistance can continue to resist repeated friction and wear, showing relatively small wear marks and pits without obvious wrinkles, peeling or falling off. Therefore, in the forging process of 304 stainless steel flange, it is necessary to select appropriate initial forging temperature and final forging temperature to effectively improve the wear performance of 304 stainless steel flange.
3. Conclusion
- 1) Both the initial forging temperature and the final forging temperature affect the room temperature and high temperature wear properties of 304 stainless steel flanges formed by forging. When the initial forging temperature gradually increases from 1100 ℃ to 1190 ℃, and the final forging temperature gradually increases from 760 ℃ to 880 ℃, the room temperature wear resistance of flanges first increases, then basically remains unchanged, and then decreases, while the high-temperature wear resistance first increases, then decreases.
- 2) When the initial forging temperature is 1130-1160 ℃ and the final forging temperature is 840-860 ℃, the 304 stainless steel flange has the best wear resistance at room temperature. Compared with forging at 1100 ℃, the wear volume of 304 stainless steel flange at 500 ℃ at 1145 ℃ decreases by 45%; Compared with the final forging at 760 ℃, the wear volume of flange at 500 ℃ at 860 ℃ decreases by 44%.
- 3) To improve the wear resistance at room temperature and high temperature, the initial forging temperature and final forging temperature of 304 stainless steel flange formed by forging are 1145 ℃ and 860 ℃ respectively.
Author: Wu Xiongxi
Source: China Flange Forgings Manufacturer: www.epowermetals.com
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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