MT/T 786-2011 in English

Analysis of the evolution of standard technology

Analysis of core technical requirements

1. Diamond composite sheet performance

The standard clearly defines the requirements for two types of composite sheets: high wear ratio type (＞30×10³) and low wear ratio type (10-30×10³). The performance degradation after welding shall not exceed 5%. The test is carried out according to JB/T3235-1999 using the grinding wheel abrasion method. Please note:

• The test environment temperature is controlled at 23±2℃
• The test value of a single piece shall not be lower than 60% of the average value
• The size of the composite piece shall comply with the tolerance band requirements
of JB/T10041

2. Key parameters of drill bit structure

Implementation suggestions

1. Selection guide

• Coal-bearing strata: Priority should be given to FTN series, the concave scraper-shaped crown can improve the slag removal efficiency
• Hard rock formation: It is recommended to use FGJ type high wear ratio composite drill bits

2. Key points of quality control

1. Carcass crack detection requires scanning with a 10x magnifying glass system
2. Thread detection must use a standard gauge, and the screwing length must be ≥3 threads
3. 3% of each batch should be sampled for brazing seam shear strength test

Impact of standard implementation

After the implementation of the new standard, the average service life of the drill bit will be increased by about 30%, but manufacturers should pay attention to the following:

• Increase investment in carcass mechanical properties testing equipment
• The welding process must meet the requirement of brazing seam strength ≥160MPa
• The packaging needs to be treated to prevent moisture and comply with the storage regulations in Article 7.4