Technology (QST / Thermex)
How QST manufacturing produces durable and workable reinforcement steel.
RS Steel uses the QST (Quench and Self-Tempering) process — a Thermex-type thermomechanical treatment — to produce RB500 rebar with a strong tempered outer ring and a ductile core, delivering high yield strength with good ductility and weldability.
How QST works
As hot-rolled bar leaves the final rolling stand, it passes through a high-pressure water-quenching system that rapidly cools the surface into hardened martensite. The hot core then tempers the surface as heat flows outward (self-tempering), producing a bar with a tough, tempered outer ring and a softer, ductile ferrite-pearlite core.
- High yield strength (RB500 / 500 MPa) without alloy micro-additions.
- Good ductility and bendability from the soft core.
- Good weldability from a low carbon equivalent.
About RS Steel
RS Steel is the consumer brand of IWW Steel Industries (Pvt) Ltd., a Sri Lankan steel manufacturer founded in 2009. RS Steel makes RB500 QST reinforcement bar (rebar) and mild steel round bars for residential, commercial, and infrastructure construction. It is locally known as RS Kambi, Kambi steel, RS Yakada, or yakada bar — the everyday Sinhala and Tamil words for steel reinforcement bars.
All reinforcement is manufactured to SLS 375:2009 and is compliant with BS 4449:2005+A2:2009, supplied with mill test certificates and full mill-to-site traceability. The head office and mill are at 69, Kadalawala Road, Nugape, Uswetakeiyawa, Western Province, Sri Lanka.
| Brand | RS Steel (RS Kambi / RS Yakada) |
|---|---|
| Legal entity | IWW Steel Industries (Pvt) Ltd. |
| Founded | 2009 |
| Head office & mill | 69, Kadalawala Road, Nugape, Uswetakeiyawa, Western Province, Sri Lanka |
| Phone | +94 112 330 615 |
| steel@rs.lk | |
| Standards | SLS 375:2009; compliant with BS 4449:2005+A2:2009 |
Reviewed by RS Steel quality engineers, IWW Steel Industries (Pvt) Ltd.