General structural steel
Structural steels usually find their application according to their tensile strength and yield point. With similar requirements to their mechanical properties the individual quality groups are (among other criteria) distinguished according to the chemical composition, liability to brittle fracture and ability for welding.
Heat treatable steel
Heat treatable steels are used according to their application properties: austenitinsation, quenching and tempering. In quenched and tempered condition heat treatable steels cover a minimum range of tensile strength of approx. 470 - 1250 N/mm2. Besides a good tensile strength, heat treatable steels are also remarkable for their high yield and ductility. The properties in the final condition should be as homogeneous as possible over the whole cross section. High-grade steels not only have low phosphorus and sulphur contents, but also more even properties, e.g. after heat treatment.
Case hardening steel
Case hardening steels are usually steels with low carbon contents, predestinated for carburisation carbonitriding, followed by hardening. Case hardening steels are remarkable for their high hardness and tough cores after treatment by surface layer hardening .The non homogenous property profile is much contributing towards the non homogenous straining profile. The most important parameter to be considered is ability for hardening, influenced by the chemical composition. Within this respect we also distinguish between quality steel and high-grade steel.
Free-cutting steel
The group of free-cutting steels has resulted from the requirements to automated machining. Fine cutting properties and chip breakability are achieved (among other things) by alloy with sulphur, manganese, lead, tellurium and bismuth. Depending on the material requirements free cutting steels are classified into soft free cutting steels, free-cutting hardening steels and free cutting heat treatable steels - all with low phosphorus and sulphur contents.
Steel with improved cold forming properties
For this purpose steels with a low yield stress, minor tendencies for strain hardening during reforming as well as a high deformability are required. Besides these characteristics, these steels should be free of internal and external defects, in order to provide an optimal cold heading product. Depending on the steel grade, a special annealing treatment, adapted to the deformation method can be applied to achieve lower final tensile properties.
Micro alloyed steel
With micro alloyed steels the strength improving effect by adding micro alloyed elements, such as vanadium, titanium, niobium and aluminium is exploited. These elements in the range of 10-² to some 10-¹ weight % form precipitations within the steel matrix, which have an influence on the preheating and reformation process and on the micro structural transformation of the steel.
Chain steel
Besides strength, brittle fracture resistance and ductility are dominant factors for chain steels. Furthermore, aging and wear resistance, ability for welding, cold shearing and cold formability are very important. The ability for welding limits the carbon content to about 0.25 %. To enhance the strength with such a low carbon content additional alloy of manganese, chrome, nickel and molybdenum produces strengths of up to 1500 N/mm2 in the chain. Aluminium is alloyed for better aging resistance and grain refinement. Good ductility is achieved by a lowest possible content of accompanying elements, like phosphorus and sulphur.
Construction / Mining
Swiss Steel AG develops and produces special products for construction and mining applications. Our latest development includes the corrosion resistant reinforcing steel Top12, the micro-alloyed reinforcing steel for enhanced static requirements Top700 and the formwork tie steel St 900/1100.
The reinforcing steel Top12 is suited for constructional elements exposed to splash water and stationary water (use of defrosting salt) and for areas jeopardized by carbonatisation. Top12 presents a reliable and economic solution for improving the corrosion resistance of reinforced concrete significantly and thus extending their lifetime. Top12 can be projected and handled according to the methods developed for black rebars. No special treatment on the construction site is necessary.
Top700 is a micro-alloyed reinforcing steel exhibiting a yield stress exceeding 700 N/mm2. The steel therefore meets high static requirements and opens up new possibilities in reinforced concrete construction.
The formwork tie steel St 900/1100 is a screwable steel exhibiting a yield stress exceeding 900 N/mm2.
All products fulfill the relevant norms and are being monitored by neutral certificate authorities.