Quenched Tempered Steel

Background of Quenched and Tempered Steel

It is possible to produce steel plates that have more than twice the strength of those produced from mild steel through a heat treatment process known as quenching and tempering.

Steel is heated to a point above its upper critical temperature and is then very quickly cooled in water. This method of cooling, known as quenching, induces a transformation in the crystalline structure of the steel which leaves it much harder.

Unfortunately, the steel in this condition is also very brittle and it is not possible to use it in many applications. A method of heat treatment for alleviating this problem is called tempering and requires the quenched steel to be re-heated although this time to below the lower critical temperature.

The result is to put toughness and ductility back into the steel and, although some of the yield strength of the quenched steel is lost, the end result of the quenching and tempering process is to produce a strong steel which is also easy to weld, bend, and fabricate generally.

As the process of quenching and tempered has been improved and refined, carbon steel plates produced this way have become stronger and it is not uncommon now to find plates with strengths of more that 1100 MPa which is four times stronger than basic structural steel.

What are the benefits of EN 10025 S690QL?

Steel with minimum yield strength of 690 MPa has proved very popular with steel users because of its availability, price, and ease of fabrication. It is able to improve the performance, durability, and safety of vehicles, lifting equipment, and steel structures. Due to the steel’s high strength, structures can be designed lighter, payloads increased, and energy used more efficiently.

In Europe the structural steel specification EN 10025 includes a range of high strength quenched and tempered steel grades and the designation S690QL gives the parameters for steel with a minimum yield strength of 690 MPa.

Brown McFarlane and S690QL plate

Brown McFarlane holds one of the largest stocks of S690QL steel plates in the UK and supplies plates from stock as well as pieces which are cut to size and shape on its computer controlled cutting machines.

Fabrication of EN 10025 S690QL Steel Plate

High strength quenched and tempered steel plate can be easily welded and fabricated but its high yield strength and tensile strength compared with mild steel means that it should be treated with some caution. We have provided information which is intended as a basic guide to various fabrication methods.

If you require more detailed advice on welding, machining, or forming then please contact any one of our offices.

About RQT 701 Quenched and Tempered Steel Plate

The steel was developed for use in applications such as mining and quarrying, process industry, material handling, construction, and earth moving. Designers, engineers, and plant operators strived to reduce weight and increase the efficiency of equipment. There are significant benefits to be had by using high strength quenched and tempered steels for maximum structura performance in extreme working environments.

Although this steel grade is no longer manufactured, Brown McFarlane offers equivalent products in our Quenched and Tempered Steel range.

Fabrication of RQT 701 Steel Plate.

RQT 701 steel plate can be easily welded and fabricated but its high yield strength and tensile strength compared with mild steel means that it should be treated with some caution. If you require more detailed advice on welding, machining, or forming then please contact any one of our offices.

EN 10025 S890QL Steel Plate

Is becoming increasingly popular with engineers and designers looking to exploit its strength to weight ratio. Use of S890 steel will ensure higher payloads for lifting and transportation equipment. A lighter truck body will allow more material to be carried while lifting booms on can be lightened, strengthened and lengthened.

S890 steel is used in applications such as cranes (mobile and loader), aerial platforms, load handling equipment, bridges, and special containers.

We find that the category of steel plate that EN 10025 S890QL falls into is called different things by different engineers. Plate of this type is variously described as:

• High Strength Quenched and Tempered Steel Plate
• High Yield Quenched and Tempered Steel Plate
• High Strength Structural Steel Plate,
• High Yield Structural Steel Plate
• High Strength Low Alloy Steel Plate
• HSLA

Brown McFarlane and S890QL Steel Plate

Brown McFarlane holds a substantial stock of S890QL steel plates in the UK. These plates are frequently sold as cut to size pieces and shapes which are produced on the company's computer controlled cutting machines but plates straight from stock for fabrication by our customers are also readily available.