PRODUCT SCIENCE

Corrosion, acid and heat resistant steels meet the highest demands. They are highly resistant to corrosive and mechanical stress, and have high strength and strain values. Their high quality ensures long-lasting security.

SUBDIVISION OF STEELS

Ferritic steels are almost exclusively pure chromium steels with a chromium content of 12-18%. The carbon content is less than 0.1%.

Their most important properties include inter alia good weldability and that these steels are magnetic; they cannot be hardened or treated with heat.

Martensitic steels are part of the chromium steels, which, depending on the quality, have had nickel (0.5-2.5%) and molybdenum (<1.2%) added. The carbon content is 0.1-1.2%. Their most important properties are inter alia that these steels are magnetic and can be thermally hardened and tempered. As a general rule, they cannot be welded. Austenitic steels are subdivided into chromium-nickel steels (e.g. 1.4306 and 1.4541) and chromium-nickel-molybdenum steels (e.g. 1.4436 and 1.4571).

These steels are suited to almost all areas of application as they can be easily deformed and processed. They are non-magnetic.

IMPORTANT ALLOYING ELEMENTS

Chromium Cr

Chromium as a carbide former prevents corrosion of the material by forming a passive layer together with oxygen.

Carbon C

Carbon increases strength and, in martensitic steels, hardening capabilities. It stabilises the austenitic structure.

Nickel Ni

Nickel Ni. This improves corrosion resistance and the absorbed energy. From a content of 7%, it converts the structure from ferrite to austenite.

Molybdenum Mo

This increases acid resistance as well as the strength of the steel. Molybdenum is a ferrite binder.

Titanium Ti

Titanium Ti. Titanium is a carbide former and is added to the alloy as a stabilising element in order to bind the carbon. As a result, greater resistance to intercrystalline corrosion is achieved without heat treatment after welding.

Niobium Nb

Niobium, like titanium, is a stabilising element.

Manganese Mn

Manganese increases strength. The resistance to wear is also increased

Nitrogen N

The addition of nitrogen stabilises the austenitic structure and increases strength.

Sulphur S

Sulphur improves machinability. Weldability decreases due to sulphur.

MECHANICAL PROPERTIES

Yield strength and yield point Rp 0.2% and Rp 1.0%

This refers to the tension related to the initial cross-section of the tensile test sample, which effects a steady plastic deformation of

0.2 and 1% to the starting length.

Tensile strength Rm

This refers to the tension related to the initial cross-section of the tensile test sample, which causes a break in the material.

Elongation at break A

This refers to the remaining elongation following a break in the sample in a tensile test.

Reduction in area Z

This value describes in terms of percentage the reduction in the cross-section measured in the tensile test compared with the original sample cross-section.

Absorbed energy KV

This value states in joule the energy that was consumed in the impact test.

Hardness HB, HV, HR

Hardness is the resistance of a workpiece surface to a harder penetrating body.