Fabrication of Quenched and Tempered Steel Plate
The range of high strength quenched and tempered structural steels held in stock by Brown McFarlane combine high yield and tensile strengths with good notch toughness while providing excellent weldability. The material is easy to fabricate as long as a few allowances are made for its high strength. The following information relates to steel grades with a minimum yield strength of 690 MPa.
Steel can be cut satisfactorily using conventional oxy-fuel gas practices, in many cases without the need for preheat, as long as cutting procedures take into account plate thicknesses and carbon equivalent values. Water jet, where no heat is generated, or plasma cutting can also be used. Care should be taken when cutting under water as the quenching effect could result in a high hardness edge forming. With all thermal cutting processes care should be taken that cut edges are free from sharp notches.
The maximum thickness that can be sheared will depend on the power available to the shearing unit and the blade material but there is no problem with cold shearing this type of plate. As a guide, when using smaller shears, the maximum thickness should be reduced by around 35% compared to S355JR plates.
RQT steels can be readily cold formed however the power required will be around 70% higher than that for mild steel of the same thickness. It is recommended that the largest possible bending radius should be used, and generally the inside radius should not be less that three times the plate thickness.
|Bend axis vs. rolling direction
||Minimum inside bending radius
||Minimum die opening
Plates can be machined and drilled using high-speed steel or cemented carbide tools. The approximate hardness of these steels can be obtained from the value of the ultimate tensile strength found on the test certificate and generally falls within the range 240-280 BHN.
The plates can be welded with the appropriate preheat. Care should be taken to avoid hydrogen cracking and there are many factors to take into consideration before welding. Full technical guidance for welding is available from the sales/technical team at Brown McFarlane.
For more information and for details of price and availability contact any of our sales teams. You can get their details by clicking here.
With yield strengths up to 900n/mm2 available from stock in thicknesses from 3 to 200mm available from stock.