U135 Hard Rock Layer Cutting Pick

During the construction of a key water diversion tunnel project in Guangdong, the construction team encountered rare and complex geological challenges—rock hardness reaching F13 grade (equivalent to uniaxial compressive strength of 130 MPa), with quartz content exceeding 30%. Frequent breakage and accelerated wear of traditional cutter bits led to a significant decline in construction efficiency, with daily excavation rates falling below 60% of the expected target. This predicament was ultimately overcome with an innovative cutter bit product. Field test data showed that after adopting the Duerbote U135 alloy composite wear-resistant coated cutter bits, consumption decreased by 25% compared to the original brand, and overall construction costs dropped by 18%, providing a reference model for hard rock construction in the industry.

I. Project Background: The "Roadblock" of F13 Hard Rock

The water diversion tunnel project is located in the mountainous area of northern Guangdong, with the stratum mainly composed of granite and quartz sandstone. Local rock hardness reached F13 grade. During the initial construction phase, a certain brand of cutter bits was used, leading to three major issues:

1.High Wear Rate: A large number of cutter bits needed replacement per single cycle (8 hours), with spare parts costs exceeding the budget by 40%;

2.High Equipment Load: Cutter bit wear increased cutting resistance, leading to a 25% rise in fuel consumption for the tunneling machine;

3.Risk of Project Delay: Daily excavation progress was slow, lagging 35% behind the planned schedule.

"At that time, we had to halt operations for 2 hours daily just to replace cutter bits, and the project contractor issued multiple warnings to accelerate progress," recalled the on-site construction manager.

II. Solution: Technological Breakthrough of U135 Cutter Bits

To address the working conditions of F13 hard rock, the Duerbote technical team proposed a dual optimization solution focusing on "material + structure":

1. Alloy Composite Wear-Resistant Coating Technology

lGradient strengthening design: An alloy composite coating was applied to the surface layer of the cutter bits, achieving a hardness of HV1750, a 30% improvement over conventional coatings;

lOptimized impact toughness: The base material used low-stress alloy steel, and through special heat treatment processes, the hardness of the bit body was maintained at 38-42 HRC, balancing wear resistance and fracture resistance.

2. Tooth Shape Adaptability Modification

lBased on the characteristics of the rock layer in the water diversion tunnel, the tooth head angle was adjusted from the standard 60° to 55°, reducing cutting resistance;

lThe shoulder width of the cutter bits was widened to prevent wear of the bit holder caused by rock dust accumulation.

3. Dynamic Monitoring and Rapid Response

lProvided hardness and metallographic test reports for each batch of cutter bits;

lEstablished a dedicated logistics channel, ensuring emergency orders were delivered to the site within 3 days.

III. Implementation Results: Dual Optimization of Efficiency and Cost

Field tests and comparisons demonstrated the significant advantages of U135 cutter bits:

lDuerbote cutter bit consumption per single cycle decreased by 25% compared to before;

lDaily excavation volume increased by 50%;

lEquipment fuel consumption decreased by 15%;

lOverall construction costs decreased by 18%.

"The stability of Duerbote U135 cutter bits exceeded expectations. Now, we save time on daily replacements, greatly alleviating schedule pressure," stated the project equipment supervisor.

IV. Technical Analysis: Three Core Advantages of Duerbote U135 Cutter Bits

1.Breakthrough in Wear Resistance

Through optimized deposition processes for composite coatings and gradient structure design, the lifespan of cutter bits in F13 rock layers was extended, showing a 40% improvement over conventional products.

2.Innovation in Impact-Resistant Structure

Finite element simulation optimized stress distribution, with实测 impact toughness reaching 70 J/cm² and a fracture rate below 0.5%.

3.Controllable Full-Cycle Cost

By reducing replacement frequency and minimizing equipment wear, the cost per meter of construction was further saved.

V. Industry Insights: Standardized Approach for Hard Rock Construction

The successful practice of this project provides replicable experience for similar projects:

lGeological Adaptability First: Customize cutter bit parameters based on rock properties to avoid the misconception of "forcing universal products to fit";

lData-Driven Selection: Quantify performance and cost benefits through small-batch field tests and comparisons;

lSupply Chain Collaboration: Choose suppliers with rapid response capabilities to reduce downtime losses.

Leveraging Technological Dividends to Tackle Hard Rock Challenges

The practice of the Guangdong water diversion tunnel project proves that under extreme geological conditions, technological innovation remains the core driver for breaking through efficiency bottlenecks. The U135 cutter bits, through the deep integration of materials science and engineering mechanics, provide a cost-effective solution for hard rock tunneling. With the promotion and application of such technological achievements, China's tunnel construction sector is expected to further overcome the limitations of "bottleneck" working conditions.