National Standards and Technical Specifications for Mine Nut Joints

The national standards for mine nut joints mainly cover areas such as coal mine support, conveyor belt connection, and hydraulic systems. The following are the key standards and technical points:

1. Youdaoplaceholder0 nuts for coal mine support ‌
High-strength nuts ‌ : must comply with the requirements of GB/T 3098.2-2000 "mechanical properties of Fasteners - Nuts - Coarse thread" or GB/T 3098.4-2000 "Fine Thread nuts", with a performance grade of no less than 8.8, and made of carbon steel or alloy structural steel (such as GB/T 3077-1999).
Hydraulic nut ‌ : bottom ring type/top ring type design, thread specifications covering M24-M48, fine thread preferred, stroke tolerance ±1.5mm, oil injection port depth 8mm, must pass Brinell hardness test 187-241HBW.
2. Mechanical joint nut of ‌ conveyor belt ‌
U-shaped buckle joint ‌ : the original MT 319-1992 standard (which has been abolished) stipulates that the tensile strength should be ≥560N/mm (for the common type) or 980N/mm (for the strong type), and it should not break in the bending test. The current standard MT/T 319-2006 replaces the old version and clearly stipulates the load strength and wear resistance requirements of mechanical joints.
Scraper conveyor bolts and nuts ‌ : trapezoidal head bolts (M20-M30) shall comply with MT 187.6-88 standard, mechanical performance grade 8.8, length tolerance ±1.5mm to ±2.5mm.
3. Youdaoplaceholder0 hydraulic system pipe joint nut ‌
Flared type B nut ‌ : in accordance with GB/T 5648-2008, thread specification M12×1.5 to M42×2, sealing cone Angle tolerance ±0°5 ', surface galvanized and passivated, suitable for coal mine hydraulic pipelines.
4. Youdaoplaceholder0 Materials and surface treatment ‌
High-temperature environment ‌ : stainless steel or nickel alloy nuts in accordance with GB/T 3098.24-2020 standard are optional, and the high-temperature resistance performance must pass the special test.
Anti-corrosion ‌ : galvanizing or phosphating treatment shall comply with the requirements of GB/T 5267-2008 "Electroplating layer of fasteners".
Association of standard systems
Core standards ‌ : GB/T 3098 series (mechanical properties), MT/T 319-2006 (conveyor belt joints), GB/T 5648-2008 (hydraulic nuts) constitute the technical framework of mine nuts.
Reference standards ‌ : including GB/T 196 (thread dimensions), GB/T 1231 (high-strength bolt connection pairs), etc., to ensure compatibility.

For specific standard texts, you can refer to the platform of the Standardization Administration of the People's Republic of China (such as GB/T 3098.24-2020) or the compilation of coal industry standards.