As the main component of shield tunneling construction, shield machine hob is composed of cutter ring, cutter body, cutter shaft and bearing, among which cutter ring is the key component for directly crushing rock and soil. The shield machine hob is generally used in hard rock formations. During operation, the hob squeezes the rock under the action of the forward power of the shield machine, forming radial cracks. Two adjacent radial cracks extend and penetrate each other, resulting in The rock blocks between the two cracks fall off to achieve the purpose of rock breaking and excavation.

When working in composite strata, especially when the upper is soft, the lower is hard or the

composite stratum, the rock breaking method of the hob changes, not only friction and extrusion, but also collision with the rock formation. This kind of force makes the surface of the

cutter ring of the hob must have high hardness and wear resistance, and at the same time, it

needs to be strong and tough inside. The current solution is to use the characteristics of laser

cladding technology to clad a layer of hard material on the cutter ring with softer hardness,

which can improve the wear resistance of the cutter ring without changing the toughness of the cutter ring itself.

• Due to the need to meet the characteristics of wear resistance and high hardness at the same time, and to ensure that the cladding layer cannot be easily cracked, the selection of cladding materials is one of the difficulties in the industry. At present, the cladding of shield machines in China is mostly imported materials, such as Kennametal, Hegrass and other brands, which are expensive, increase production costs, and are not conducive to the popularization and promotion of technology. According to the use characteristics of shield machine hob, Chengfeng Materials has improved the ratio of cladding materials many times, and has conducted in-depth exchanges with hob processing manufacturers, repeated tests and adjustments, and finally developed a perfect match with the shield machine hob. Suitable cladding material - nickel-based high-hardness, wear-resistant and crack-free cladding alloy powder. #shield machine hob laser cladding# #nickel-based cladding alloy#

Nickel-based high-hardness, wear-resistant and crack-free cladding alloy powder has the characteristics of high hardness, high wear resistance and corrosion resistance, and is suitable for laser cladding on the surface of superhard material tools. Application scenarios include mining, tunnel excavation, seabed mining, etc.

Microstructure of nickel-based high-hardness,

wear-resistant and crack-free cladding alloy powder

Product Features

1. High hardness. Customized tungsten carbide has high purity, high sphericity, low free carbon, dense cladding layer without pores, and the hardness of the test data is significantly higher than that of general laser cladding materials.

2. High wear resistance. The self-developed nickel-based alloy has strong corrosion resistance, and has a stronger coating affinity with tungsten carbide, which reduces the abrasive wear during use.

3. No cracking. The unique composition ratio and processing technology ensure that the material can be formed stably during use, and there is no cracking of the cladding layer or the bonding layer under high tungsten carbide concentration.

4. Strong bonding force with the substrate. Nickel-based tools have extremely high wettability to the steel matrix and form deep metallurgical bonds during the cladding process. As a result, the cladding layer has a higher bonding force with the substrate, and the tensile strength of the sample block test is as high as 1400MPa.

5. High toughness, high temperature impact resistance. The nickel-based formula material has excellent high-temperature mechanical properties and is capable of working in a high-temperature impact environment of 800 °C.

6. High cost performance. The powder manufacturing is domestically produced on a large scale, the quality can replace imported cermet products, the price is affordable, and the stock is sufficient.

Test data reference

Micromorphology of cladding layer

Cladding test renderings

Grinding effect of cladding layer

Cladding test chart

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