Rockbolt 20TBar – Gewi

HSCC500 is a high strength, quenched and self-tempered steel designed for mining and civil construction applications.  Available in commercial finish.

20TBAR is a hot-rolled, continuously threaded 20mm deformed bar.

Typical Application – Mine roof support.

WELDING

Prehead or post heat not required.  Hydrogen controlled welding processes and electrodes such as  GMAW,  FCAW and low hydrogen  MMAW  must be used for all weld types. Matching strength W55x  (E55x)  or  W62x  (E62x)  type consumables are required for all load-bearing butt welds.

Interpass temperature should be limited to 200oC maximum for all joints. 

BILLET FEED Billet feed grade: 1AA1017, (Quench and Temper)

Sampling protocol as per L-QC-TM-75-RML01

Sections as per drawing SR28089 Rev E

Note: Ensure all dimensions are within tolerance.

Each rib should be of uniform height along its length, with no ‘scallop’ and/or ‘tit’ present. Supervisor must be informed and the product placed on hold for re-inspection if any unevenness is detected. Use gauge for thread alignment check. 

Shear cut –  Shear cut shall be checked every hour by labman.

MECHANICAL PROPERTIES  

Sampling protocol as per L-QC-TM-75-RML01  

Cross Section Area:                   300 mm  at 19.54 mm nominal core diameter

Yield Stress (MPa):                   540 min.

UTS (MPa)                                600 min

EL (5d) (%):                              16 min.

Shear Strength:                         (0.7 x UTS)

Length tolerance                          +50mm, -0

Nominal bundle mass                   2.00 tonnes  (+/-5%, range 1.90 – 2.10 tonnes)

Securing

7,010 mm to 12,000 mm length

5 wire ties equally spaced, end ties wire 300-500 mm from bundle ends

Tagging

One face tag per bundle, securely riveted to end of bar.

Tag Grade K1017    Face tag colour –    White   Bar End Colour Code- no colour code

For further details please contact your closest Ground Support Representative

*Different length Gewi Bar can be ordered on request