Cromanite Technical Data
Please note
that Columbus has discontinued manufacturing this material
and that the following information is published for
academic purposes alone.
Summary
CROMANITE is a high nitrogen austentic stainless steel which has a unique combination of strength, toughness, ductility, work hardenability and corrosion resistance. The steel performs exceptionally well in materials handling applications, where there is wet sliding abrasion and high impact abrasion. Cromanite is also an excellent candidate material for a variety of high strength applications even at elevated temperatures. In addition, cromanite is a weldable stainless steel that can be readily cut, machined and formed.
CROMANITE is a high nitrogen austentic stainless steel which has a unique combination of strength, toughness, ductility, work hardenability and corrosion resistance. The steel performs exceptionally well in materials handling applications, where there is wet sliding abrasion and high impact abrasion. Cromanite is also an excellent candidate material for a variety of high strength applications even at elevated temperatures. In addition, cromanite is a weldable stainless steel that can be readily cut, machined and formed.
Plate
can be supplied in the hot rolled and annealed condition
(HRA) or in the hot rolled, annealed and descaled condition
(No 1).
Properties
CHEMICAL
COMPOSITION
Cromanite contains a nominal 19% chromium, 10% manganese and 0.5% nitrogen. The steel has received a European standard EN 10 088 listing designated as type 1.3820.
Cromanite contains a nominal 19% chromium, 10% manganese and 0.5% nitrogen. The steel has received a European standard EN 10 088 listing designated as type 1.3820.
MECHANICAL
PROPERTIES
In the annealed condition, cromanite has a typical yield strength of 550 MPa, a tensile strength of 850 MPa and an elongation of 50%. The hardness level is typically 250 HB which increases to a level of approximately 500 HB under impact conditions. It has an impact toughness of about 250 J.
In the annealed condition, cromanite has a typical yield strength of 550 MPa, a tensile strength of 850 MPa and an elongation of 50%. The hardness level is typically 250 HB which increases to a level of approximately 500 HB under impact conditions. It has an impact toughness of about 250 J.
CORROSION
RESISTANCE
The resistance of cromanite to reducing acids is similar to that of the ferritic stainless grade AISI 430, while its pitting resistance (in chloride solutions) is similar to that of the austenitic stainless steel grade AISI 304.
The resistance of cromanite to reducing acids is similar to that of the ferritic stainless grade AISI 430, while its pitting resistance (in chloride solutions) is similar to that of the austenitic stainless steel grade AISI 304.
Like
AISI 304, cromanite is susceptible to chloride cracking,
but it is largely resistant to hydrogen embrittlement.
In addition, sensitization after welding does not occur.
CORROSION
WEAR RESISTANCE
Cromanite has been specifically designed to have a combination of high strength, toughness and ductility with a high work hardening rate. Cromanite will work harden under impact conditions to a level of 500 HB. This work hardening behaviour is similar to Hadfields manganese steel.
Cromanite has been specifically designed to have a combination of high strength, toughness and ductility with a high work hardening rate. Cromanite will work harden under impact conditions to a level of 500 HB. This work hardening behaviour is similar to Hadfields manganese steel.
However,
unlike Hadfields manganese steel, cromanite is a stainless
steel with excellent weldability and thus it can also
be easily fabricated.
Cromanite
performs exceptionally well in high impact wear environments,
especially where the environments are corrosive.
A
high impact environment will ensure that cromanite will
work harden, resulting in the steel being able to absorb
large amounts of energy before wear occurs.
CUTTING
Cromanite, like other stainless steels, cannot be cut with a conventional oxy-acetylene torch due to the high chromium content.
Cromanite, like other stainless steels, cannot be cut with a conventional oxy-acetylene torch due to the high chromium content.
Plasma
cutting and profiling of cromanite is the fastest and
most economical thermal cutting method available and thicknesses
of up to 50 mm can be cut successfully.
Laser
cutting and profiling of cromanite can be done up to a
thickness of 10mm.
Cromanite
can be sheared successfully. It has a shear strength
50% higher than the 300 series stainless steels.
This should be taken into account when determining the
maximum shearing capacity on any particular shear.
WELDING
Good results have been obtained using filler metals such as stainless steel types 309 and 307 and duplex types such as 2507/P100, 22/09 and CN 23/12Mo - A, welded by the MMA (SMAW or stick welding) method.
Good results have been obtained using filler metals such as stainless steel types 309 and 307 and duplex types such as 2507/P100, 22/09 and CN 23/12Mo - A, welded by the MMA (SMAW or stick welding) method.
The
welding of cromanite to itself is quite straightforward
using the manufacturers recommended parameters.
Due
to the higher thermal conductivity of cromanite versus
the resistively of the electrodes, these electrodes
must be run at the higher end of the recommended amperage
range and if necessary even higher.
Care
should be taken to avoid damage to electrode coatings
due to overheating. Distortion effects are similar
to the 300 series stainless steels and care must be taken
to reduce or eliminate this.
When
welding cromanite to 3CR12 with the MMA process, electrodes
such as types 307 and 309 should be used. When welding
cromanite to mild steel, type 309 electrodes with their
higher chromium content are preferred, thus reducing dilution
effects.
The
higher end of the amperage range should be used to avoid
lack of fusion type defects. Distortion effects
are similar to the 300 series stainless steels and care
must also be taken to reduce or eliminate this.
When
selecting a filler material for welding cromanite, it
is important that application be considered. This
is due to the fact that the strength of the weld metal
may not match that of the parent metal.
MACHINING
When machining cromanite, heavier feeds and slower speeds should be used to reduce tool build up and minimise work hardening. Fabricators with experience in machining stainless steels have not encountered problems with the machining of cromanite plate.
When machining cromanite, heavier feeds and slower speeds should be used to reduce tool build up and minimise work hardening. Fabricators with experience in machining stainless steels have not encountered problems with the machining of cromanite plate.
Cromanite
showed no significant differences in machinability compared
to 316L stainless steel in various trials. If difficulty
is experienced with machining, then Ti nitrided tools
should be used.
Applications
Cromanite
is an excellent candidate for materials handling applications
involving wet sliding abrasion and wet high impact abrasive
wear. This is because it has an excellent combination
of strength and toughness, has the work hardening ability
of Hadfields manganese steel, and the added advantage
of good corrosion resistance.
In
addition, cromanite has great potential for variety of
high strength applications due to its excellent strength
both at room temperature and at elevated temperatures.
Uncoated
materials exposed to corrosive environments can form a
protective corrosion film on the surface. Abrasion
removes this surface film and damages the newly exposed
bare metal, which is left vulnerable to further corrosive
attack. In such cases, materials with poor corrosion
resistance, such as carbon steels, have an unacceptable
wear rate.
Technical
Data
CHEMICAL COMPOSITION
CHEMICAL COMPOSITION
| Carbon | 0.08 % maximum |
| Silicon | 1.00 % maximum |
| Manganese | 9.50 - 11.00 % |
| Phosphorus | 0.045 % maximum |
| Sulphur | 0.015 % maximum |
| Chromium | 18 - 20 % |
| Nickel | 1.00 % maximum |
| Nitrogen | 0.4 - 0.6 % |
TYPICAL
PHYSICAL PROPERTIES
| Density | 7 810 kg/m3 |
| Young's Modulus | 200 GPa |
| Poisson's Ratio | 0.29 |
| Specific heat capacity | 410 J/kgK |
| THERMAL CONDUCTIVITY | |
| 20oC | 36.9 W/mK |
| 100oC | 32.2 W/mK |
| 500oC | 39.0 W/mK |
| COEFFICIENT OF THERMAL EXPANSION | |
| 0 - 100oC | 15.7 x 10-6K-1 |
| 0 - 300oC | 17.3 x 10-6K-1 |
| 0 - 500oC | 18.7 x 10-6K-1 |
| ELECTRICAL RESISTIVITY | |
| 20oC | 75 mWcm |
| 100oC | 85 mWcm |
| 500oC | 117 mWcm |
MECHANICAL PROPERTIES
| MINIMUM | TYPICAL | |
| 0.2% Proof Strength (MPa) | 450 | 550 |
| Ultimate Tensile Strength (MPa) | 800 | 850 |
| % Elongation (proportional) | 40 | 50 |
| Impact Toughness (J) | N/A | 250 |
| Hardness (HB) | N/A | 250 |
Mechanical
properties at room temperature (20oC)
TYPICAL
MECHANICAL PROPERTIES AT ELEVATED TEMPERATURES
| 500oC | 800oC | |
| 0.2 % Proof Strength (MPa) | 270 | 200 |
| Ultimate Tensile Strength (MPa) | 570 | 330 |
Short time elevated temperature tensile strength.
Info By :
http://www.askzn.co.za/tech/tech_grade_cromanite.htm
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