Martensite
Should normal carbon steel be heated into the austenite phase and quenched rapidly, the atoms are trapped , preventing the phase to change causing a shearing process and forming a complex body centre tetragonal material none as martensite. This material is magnetic and characterised by high strength and brittleness by having such internal stress. The internal strain may be controlled easily by heat treatment to particular desired level. Having a relatively high carbon content (0.1 – 1.2%) they are plain chromium steels with 12 -18% chromium.
Basic Properties
- Moderate to good corrosion resistance, depending on level of chromium
- Magnetic
- Can be hardened by heat treatment
- Difficult to weld
- Not as good formability as austenitic grades
Typical Applications
- Cutlery & Knives
- Food Processing Cutters
- Surgical Instruments
- Shafts
- Pins
Duplex Alloys
Duplex Stainless steels do not fully generate a austenite structure thus forming a combined structure of both austenite and ferrite. They are characterised by high resistance to stress corrosion cracking, increase resistance to chlorine and higher tensile strength. These grades of stainless steel contain high levels of chromium (18 -28%), relatively low levels of nickel (4.5 - 8%) and often contain high levels of molybdenum (2.5 – 4%)
Basic Properties
- High resistance to stress corrosion
- Increased resistance to chlorine attack
- High tensile strength
- Easily welded
- Good formability
Typical Applications
- Marine Industry
- Heat Exchangers
- Water Treatment Plants
- Petrol-Chemical Plants
- Civil Engineering
Precipitated Hardened
This category of stainless steels are formulated so that they are supplied in a solution treated condition that enables them to be machined and hardened following fabrication. This process is carried out in a single relatively low temperature process.
Basic Properties
- Moderate to good corrosion resistance, depending on level of chromium
- Magnetic
- Easily welded
- Exceptional high strength
Typical Applications
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