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MARTENSITIC STAINLESS

ELG Carrs Stainless Steels complement their range of austenitic and Duplex steels with martenistic steels to supply to oil and gas customers.

Martensitic steels have a higher carbon content than ferritic steels. The carbide particles are closely packed in a matrix of ferrite. The boundaries between the ferrite crytals are seldom clearly defined. As shown by the micrograph, the carbide particles are rather small, rounded and evenly distributed in the steel.

Martensitic steels are magnetic and can be hardened. After tempering, they are easily worked with cutting tools. They are also easily welded.

The chemical resistance is the highest in the hardened state because of the homogeneous structure obtained by hardening, that is, there are no points on the surface of the material more susceptible to chemical attack than the rest of the surface.

Steels with approx. 14% chromium and 0.09% carbon are suitable for knives, armatures, etc. - with a carbon content of 0.20%, for components in steam machinery, cast furnace parts such as hearths, and annealing boxes - with carbon content of 0.30%, for edge tools such as knives and scissors, for various other instruments, and for springs.

Steel with approx. 17% chromium, 0.20% carbon, and about 0.7% nickel are used for constructional elements subjected to more severe corrosive attack, such as shafts and rotors in compressors for nitreous gases, in nitric-acid pumps.