The crane roller is an important load-bearing component in the crane. It is made of Q345b. It is usually subjected to large shear stress during work. After long-term use, the bearing surface will suffer severe wear and peeling (such as wear spots, deep grooves, and pits). ), thus affecting the stability during lifting and causing serious lifting accidents. In the picture below, serious deep grooves and pits have appeared on the bearing surfaces of the drum and gear ring of Eastern Electric Power Co., Ltd., which seriously affects the stability of the crane operation. After evaluation, laser cladding was used to repair the worn surfaces, and finally made them Restore dimensions and meet mechanical performance requirements.

Repair of the inner ring bearing surface of the crane drum

The sealing cover is the carrier of the roll neck seal. If there are sealing requirements, the workpiece cannot be deformed after wear-resistant treatment, and it is required to have sufficient machining allowance to ensure that its shape and dimensional accuracy can be restored.

1) Technical requirements for laser cladding of sealing cover:

• a) The sealing cover is the carrier of the oil film-bearing roll neck seal, and there is friction and wear with the rubber seal during operation;
• b) The sealing cover is made of 35# steel, and the working surface needs to be wear-resistant. The thickness of the wear-resistant layer: 0.2-0.5mm;
• c) The cladding layer has high hardness, surface hardness value: ≥70HRC, and has good corrosion resistance to prevent it from rusting;
• d) The sealing cover works in a high-temperature, water-drenched environment is prone to rust, and requires overall anti-rust treatment.

2) Technical solutions for wear-resistant strengthening and laser cladding of the working surface of the sealing cover:

Using our QS-Ni05 material, laser cladding introduces uniform cladding on the surface of the workpiece. QS-Ni05 material is a composite material. Due to the presence of ceramic particles, the wear resistance is greatly improved, and the parent Ni-based material has very good rust and corrosion resistance. The thickness of the laser cladding wear-resistant layer is controlled to be above 0.7mm and more than 0.25~0.3mm is reserved to ensure that the thickness of the wear-resistant layer is about 0.4mm.

3) Laser cladding material and process test results:

QS-Ni05 is a commonly used wear-resistant material in our material library. It has the advantages of a stable molding process, strong oxidation resistance, and wear resistance at normal and high temperatures.

The round particles in the picture with a size of about 50 to 120 μm are ceramic particles. The ceramic particles are dispersedly distributed in the matrix alloy cladding layer, and there is less dissolution around them, indicating that the ceramic particles and the matrix have a certain degree of mutual dissolution and Diffusion, the two combine very strongly. In addition, the mother matrix and the steel matrix show good metallurgical bonding, and the fusion shows no defects such as cracks and holes.

QS-Ni05 hardness: Table 3.8 QS-Ni05 hardness test results

QS-Ni05 is a composite material containing ceramic particles. The parent alloy serves as the bonding phase (soft phase) and the ceramic particles serve as the hard phase, which significantly improves wear resistance. The hardness value measured in the figure is the parent alloy of hardness.

4) Process application cases:
Repair of crane roller bearing surface and gear ring outer surface

Substrate Q235, cladding material QS-Ni05, cladding thickness 4mm
The crane roller is an important load-bearing component in the crane. It is made of Q345b. It is usually subjected to large shear stress during operation. After long-term use, the bearing surface will suffer severe wear and peeling (such as wear spots, deep grooves, and concavities). pit), thus affecting stability during lifting and causing serious lifting accidents. In the picture below, serious deep grooves and pits have appeared on the bearing surfaces of the drum and gear ring of Eastern Electric Power Co., Ltd., which seriously affects the stability of the crane operation. After evaluation, laser cladding was used to repair the worn surfaces, and finally made them Restore dimensions and meet mechanical performance requirements.