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Heat-treated Threaded Deformed Rock Bolt

Heat Treated Thread Deformed Bar - Rock Bolt Parts

Components of Heat Treated Threaded Deformed Bar Rock Bolt

Heat treated threaded deformed rock bolt is composed of following parts: 1 Bar; 2 Nut; 3 Nylon Washer; 4 Dome Washer; 5 Plate;
L: Length of Bar; l Length of Threaded Portion; m Diameter of Bar

Anchoring Ways of Rock Bolt

Heat Treated Threaded Deformed Bar Rock Bolt

There are 3 major ways of anchoring the rock bolts: mechanical, grouted, and friction. The most common form of mechanically anchored rock bolt uses an expansion shell. A wedge attached to the bolt shank is pulled into a conical expansion shell as the bolt is rotated. This forces the shell to expand against the wall of the borehole. The two mechanisms by which the shell is anchored against the borehole wall are friction and interlock. A preload can be applied to the rock surface by tensioning the bolt with an attached hanger or face plate, which are designed to distribute the load uniformly onto the surrounding rock.

Rock Bolt Safety Certificates

Rock Bolt for Roof Bolting Support

The main function of rock bolt is roof bolting, which is to bind stratified or broken rock layers together to prevent roof falls. In order to achieve this purpose 4 basic theories have been established for roof bolting:

  • Simple skin support;
  • Suspension of a thin roof layer from a massive bed;
  • Beam building of laminated strata;
  • Keying of highly fractured and blocky rock mass.

Mechenical Properties of Threaded Deformed Rock Bolt

Steel GradeYield StrengthTensile StrengthElongation After FractureElongation under Max ForceImpact Absorb Energy
Rel/MPaRm/MPaA/%Agt/%kv2/J
NOT LESS THAN
Industrial StandardMG335/MG4003355001540
MG50050070022100
Our company Standard60060075019990
700700850177.580
785785930165.560
8308301030154.550

Available Dimensions of Threaded Deformed Rock Bolt

Suface TypeNominal Diameter Dn/mmNominal Cross SectionSn/m㎡Weight per meter g/mTop strength level MPa
Levorotation, no longitudinal rib16201.061578800
Levorotation, no longitudinal rib18254.471998800/1080
Levorotation, no longitudinal rib20314.162466800
Levorotation, no longitudinal rib22380.132984800
Levorotation, no longitudinal rib25490.883853800/1080
Levorotation, no longitudinal rib28615.754834800
Levorotation, no longitudinal rib32804.256313800/1080

Production Process Compare of High and Medium Tensile Rock Bolt:

Rock Bolt Tensile StrengthProduction Process
335MPa ~ 500MPa (Medium)Raw Material — Reduce diameter — Screw thread — Test — Packaging — Stock
600MPa ~ 700MPa (High)Raw material — Heat Treatment — Mechanical Property Test — Sawing/Cutting — Reduce diameter — Screw thread — Test — Packaging — Stock

Application of Threaded Deformed Rock Bolt :

High Tensile Strength Rock Bolts are applicated in structure and construction projects as follows:

  • Coal mining
  • Hard rock mining
  • Civil construction
  • General construction
  • Geotechnical and Shoreline
  • Bridges
  • Dams
  • Infrastructure
  • Tunnels
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