ROQLAST TH 500

ROQLAST TH 500 Abrasion Resistant Steel Plate

ROQLAST TH 500 is a quenched and tempered high-strength alloy steel which has superior abrasion resistance, micro-cleanliness, and toughness.  This steel is an advancement on ROQLAST TH 360 and ROQLAST TH 400 grades.
The superiority of ROQLAST TH 500 is due to desulpherisation and inclusion shape control characteristics.  
 

 2.    MECHANICAL PROPERTIES.  (TYPICAL VALUES)

2.1    Hardness.
The hardness range is as follows:
 

 
2.2     Tensile Strength.
ROQLAST TH 500 is produced to meet specific minimum surface hardness requirements and not tensile requirements, however typical stress strain data is as follows:

Tensile Strength                            1 880 MPa max.
Yield Strength                                1 650 MPa max.
Elongation (50 mm)                       14 %
R.A. at point of fracture                 35%

2.3    Charpy V. Notch Impact Resistance Tests.
(Typical Value)

50-60 Joules at Ambiant Temperature.  

3.     FABRICATION

3.1    Cold Forming.
Limited Cold forming may be performed on ROQLAST TH 500.
Edge preparation by grinding is advised.
Flame cut edges should be tempered at 200oC max. prior to grinding the edges if difficult radii are to be encountered.

N.B.
Major forming should be done transverse to the rolling direction and not parallel to it.

3.2    Flame Cutting.
Modern flame cutting practice may be employed, however it is advisable to pre-head from 65 to 120 degrees C immediately ahead of the torch.

3.3    Hot-working.
ROQLAST TH 500 is tempered at a temperature of 200-400 degrees C and to ensure that full hardness is retained, the steel should therefore not be hot worked at temperatures exceeding 250 degrees C.

3.4    Drilling.
Alternative attachment methods such as hole fabrication with oxy-fuel process or stud welding should be considered.  Drilling of this plate is difficult and costly.  

4.   Welding

When welding the wear and abrasion resistant steels the risk of hydrogen induced cracking (delayed cracking or cold cracking) must be minimised. The presence of hydrogen, combined with stresses in the welded joint, are the main cause of this type of cracking.

The risk of cracking can be minimised by:

* ensuring that the surfaces to be welded are dry and free of any contamination.

* applying the correct preheat. Preheating is most important in tack welding and in welding the root run. The recommendations as laid out in EN1011 should be applied while considering the higher hardness and strength of these steels

* minimising the shrinkage stresses caused by welding. This can be achieved by ensuring a good fit between the workpieces    and a well planned sequence of weld runs (balanced welding).

* selecting a filler metal with a low hydrogen content. HD ≤ 5ml / 100g.

APPLICATIONS

• Bucket Lips
• Bulldozer blades and mould boards
• Chutes (ore, coal, gravel etc)
• Coal screens
• Conveyor buckets
• Hoppers (ore, coal, gravel etc)
• Mine skip plates and liners
• Mine scrappers
• Screens (ore, coal, gravel etc)
• Dragline components
• Dump truck beds and liners
• Fan housing liners
• Baffle plates
• Blasting screens
• Brick and tile dies
• Concrete mixer spiral strips
• Foundry shake-out machines
• Shovel buckets and various other wear plate applications
• Mixer blades
• Sand and shot blasting equipment
• Tongs