Based on the use of bucket teeth in production, according to the components of bucket teeth, they can be divided into the following types:
1. High manganese steel bucket teeth
High manganese steel is used as the material of bucket teeth earlier. At present, the vast majority of excavators’ bucket teeth still use high manganese steel materials. Due to the single austenite structure of high manganese steel, hard materials are easy to work hardening. When soft materials are encountered, the work hardening phenomenon is not obvious, resulting in low hardness and poor wear resistance. Sometimes, the excavation effect is not as wear-resistant as ordinary carbon steel.
2. Surfacing of bucket teeth
Surfacing welding of bucket teeth is a layer of wear-resistant alloy with higher hardness on the tip of bucket teeth during casting. The surface of the bucket tooth made by this method is tough, with good wear resistance and impact resistance, which is suitable for mining objects with medium hardness. Because the bucket tooth is a casting with poor weldability, it needs preheating treatment before welding, otherwise it is easy to appear welding cracks. Therefore, preheating is the key step before surfacing welding. Because of the bad working conditions of the bucket teeth, it is easy to peel off the welding layer in use, so the product quality of the surfacing bucket teeth is directly related to the technical level of the workers. Manual welding is adopted in the welding process, which affects the production efficiency of surfacing bucket teeth.
3. Cast in bucket teeth
Casting bucket teeth is a hot technology which has been widely studied at home and abroad in recent years. The technology is to insert the prefabricated block of wear-resistant material into the bucket tooth when pouring at the tooth tip. The cast-in bucket tooth has high hardness, wear resistance and good impact toughness. It is very important that the combination of the two metals is firm or not. The characteristics of this method are easy to control the proportion of wear-resistant parts, the production process is not complicated, and the prefabricated block needs to be pretreated. If the process is not up to standard, the bonding strength between materials is low and the insert is easy to fall off in use. In the subsequent heat treatment process, cracks will appear in the inserted part of the bucket teeth, which will lead to the scrapping of the products.
4. Low carbon alloy bucket teeth
Compared with the traditional high manganese steel bucket teeth, the low alloy material bucket teeth are used in a wider range of mining conditions. The low alloy steel has enough toughness, and its carbon content is generally less than 05%, Si, Mn and other alloying elements are the main alloying elements. The wear resistance of low alloy steel is 1-3 times better than that of high manganese steel due to the low alloy content, low cost and long service life. This kind of steel has low carbon content, low sensitivity to notch and high fatigue strength. Low carbon alloy steel after heat treatment will appear high hardness martensite structure, carbide fine, uniform, good roundness, hardness increase at the same time also improve the wear resistance of materials, so the appropriate heat treatment process is the guarantee of low carbon low alloy steel to obtain higher strength, hardness and good toughness. According to the above analysis, low carbon alloy steel is one of the ideal materials for abrasive wear.