Preliminary Study on the Mechanism and Preventive Measures of Delayed Crack Defects in Cutting of Thick Gauge Wear-resis
As an important member of non-metallic materials, thick gauge wear-resistant steel plates have good wear resistance and special properties, so it is widely used in machinery, civil engineering and other fields. However, due to the high hardness of thick gauge wear-resistant steel plates, it is very difficult to cut and is prone to delayed crack defects. Therefore, this paper aims to explore the mechanism of delayed crack defect and corresponding preventive measures in the cutting of thick gauge wear-resistant steel plate.
2 Mechanism of Delayed Crack
The main cause of delayed crack defect in the cutting of thick gauge wear-resistant steel plate is thermal fatigue caused by cryogenic shock and thermal shock, which is caused by the rapid cooling and heating of the workpiece surface during the cutting. Figure 1 shows the mechanism of delayed crack in the cutting process of wear-resistant steel plate.
The mechanism of delayed crack in the cutting process of wear-resistant steel plate
When the cutting temperature is higher than the brittleness temperature of the thick wear-resistant steel plate, a large amount of thermal expansion and contraction will cause a significant difference in temperature between the root of the kerf and the wear-resistant steel plate. This temperature difference is too large and cannot be absorbed, which will cause a thermal shock and an instantaneous cryogenic shock to occur in the cutting part, resulting in thermal fatigue damage of the cutting part and a delay crack. During the cutting process, due to the friction between the cutting edge and the workpiece surface, a high temperature will be generated, which will cause high temperature heat treatment at the root of the cutting part and the upper, middle and lower sides of the kerf. At the same time, the cutting part is forced to cool rapidly and present a state of cryogenic shock, which will make the cutting part brittle and cause thermal fatigue failure in the cutting part, further resulting in delay crack defect.
3 Preventive Measures for Delayed Crack
In order to prevent the occurrence of delayed crack defect in cutting of thick gauge wear-resistant steel plate, the following preventive measures can be taken:
(1) Reduce the cutting temperature: The cutting temperature of thick gauge wear-resistant steel plate cutting should be reduced as much as possible. It is suggested that the cutting speed should be adjusted according to the cutting material, the cutter is replaced frequently, the cutting fluid is added properly, and the cutting edge is maintained.
(2) Pay attention to processing techniques: Attention should be paid to the selection of cutting tools and the optimization of cutting parameters. The cutting tool used in thick gauge wear-resistant steel plate cutting should be as sharp as possible, and the rake angle should be appropriately increased to reduce cutting force, so as to reduce heat generation during cutting and reduce cutting temperature.
(3) Increase the cutting layer: It is suggested to increase the cutting layer in the processing of thick gauge wear-resistant steel plate, properly reduce the cutting width of each layer, and use multiple passes cutting technology as far as possible, so as to reduce the temperature difference between cutting part and wear-resistant steel plate, reduce thermal fatigue damage of cutting part and delay crack defect.
By analyzing the cutting process of thick gauge wear-resistant steel plate, it is found that the main cause of delay crack defect is thermal fatigue due to the rapid cooling and heating of the working surface during the cutting process, which will cause the fracture of the cutting part. In order to prevent the occurrence of delayed crack defect, it is necessary to reduce the cutting temperature as much as possible, pay attention to the selection of cutting tools and the optimization of cutting parameters, and increase the cutting layers as far as possible.
Conatct us
