Blasting nozzles are a key component in a blasting system, designed to direct high-velocity abrasives onto surfaces for cleaning, shaping or surface treatment. Key requirements for blast nozzles include:
Durability: Made of wear-resistant materials such as silicon carbide, boron carbide or silicon nitride to withstand abrasive particles and high pressures.
Optimal Size: The nozzle's orifice size should match the compressor's capacity and abrasive type for efficient blasting.
Shape: The nozzle shape (straight bore, venturi, etc.) affects the velocity and pattern of the abrasive stream, with venturi nozzles being more efficient and providing greater coverage.
Pressure Tolerance: The nozzle must be able to withstand the operating pressures of the blasting system without deforming or failing.
Compatibility: It should be compatible with the blasting media and equipment, ensuring smooth operation and the desired surface finish.
Ease of Maintenance: Should allow for easy replacement or cleaning to maintain performance and minimize downtime.
Selection of Blast Nozzle Insert Materials
An essential component of the right blasting equipment is the selection of the right blasting nozzle, commonly also called blast nozzle insert. Sintered silicon carbide, hot pressed boron carbide as well as silicon nitride have extremely high hardness, which makes these materials an excellent choice for nozzles and wear pads in high-wear applications.
The decisive factor in choosing the right nozzle is the selection of the right nozzle bushing. At Unipretec, we mainly distinguish between three different bushings:
Boron carbide blast nozzle: Very hard, with a Mohs hardness of about 9.5, it is one of the hardest materials after diamond and cubic boron nitride. It's very light at the same time, approx. 2.52 g/cm³, which makes it ideal for weight-sensitive applications, but it is more sensitive to shocks, as this material is relatively brittle and less ductile than Si3N4 and SiC, making it suitable for stationary applications. The most expensive due to its extreme hardness and difficulty in manufacturing.
Silicon carbide blast nozzle: Also very hard, with a Mohs hardness of about 9.2, it is suitable for wear-resistant applications. It is slightly denser (about 3.1 g/cm³), but still very light compared to metals. It has excellent wear resistance and is often used in abrasive and corrosive conditions. It has excellent thermal conductivity and thermal shock resistance, but slightly inferior to Si3N4. It has good strength, but the fracture toughness is lower than Si3N4. Nozzles with silicon carbide inserts are all-round nozzles suitable for daily use in different places and with different blasting media. The production process is simple, so the cost is the lowest.
Silicon nitride blast nozzle: Slightly lower in hardness than the other two, with a Mohs hardness of about 8.5, but still very suitable for structural applications. It has a density of 3.2g/cm³ and is relatively light. It has excellent thermal shock resistance due to low thermal expansion and high fracture toughness. It has higher fracture toughness, strength and wear resistance than silicon carbide. Silicon nitride nozzles need to be formed by isostatic pressing, so the cost is higher than silicon carbide nozzles.
Each user must find the right lining and the right price/performance ratio for his or her job. In addition to the nozzle's construction, the nozzle's operation also plays a decisive role in the durability and thus the economic success of the blasting job.
The Unipretec product line has a wide range of blast nozzles, all of which meet certain purposes. In addition to the common pressure blast nozzles, we also offer injector nozzles and water blast nozzles (wet blast heads).
Contact Information
If you have any questions about products or services, please contact us immediately and we will reply to you within the first time.
Address: No.153, Yuehua Road, Huli District, Xiamen, China
Tel: +0086 18650119402
Email: info@unipretec.com
