xxx

la fonte alliée KALMETALL-C : fonte au chrome ou au manganèse de haute résistance aux usures par frottement et par chocs
kalenborn.de
KALMETALL-C hard casting, chromium or manganese casting characterized by high sliding wear resistance and high impact wear resistance respectively
kalenborn.de

Tous les éléments des grilles sont réalisés en fonte d'acier au chrome de qualité supérieure et de forte épaisseur et résistent [...]
viessmann.be
All grate elements are made of high quality, thick-walled chromium steel casting and can withstand even the highest temperatures.
viessmann.biz

La fonte d'acier au chrome molybdéne possède, en raison de sa grande dureté, une résistance à l'usure beaucoup plus importante [...]
kagema.com
The alloyed cast iron of chromium-molybdenum has a significantly higher resistance to wear than cast iron JL 1040 (GG-25) or other cast materials.
kagema.com

La coque est en acier au chrome-nickel à l'intérieur et à l'extérieur, et la chambre de séchage est isolée.
draeger.com
Their inner and outer housing is made from chrome nickel steel with an insulated drying chamber.
draeger.com
http://www.linguee.fr/francais-anglais/search?source=auto&qu...

Cast iron is a group of iron-carbon alloys with a carbon content greater than 2%.[1] The alloy constituents affect its colour when fractured: white cast iron has carbide impurities which allow cracks to pass straight through. Grey cast iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material breaks.
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Nickel is one of the most common alloying elements because it refines the pearlite and graphite structure, improves toughness, and evens out hardness differences between section thicknesses. Chromium is added in small amounts to the ladle to reduce free graphite, produce chill, and because it is a powerful carbide stabilizer; nickel is often added in conjunction
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Grey cast iron is characterised by its graphitic microstructure, which causes fractures of the material to have a grey appearance. It is the most commonly used cast iron and the most widely used cast material based on weight. Most cast irons have a chemical composition of 2.5–4.0% carbon, 1–3% silicon, and the remainder iron. Grey cast iron has less tensile strength and shock resistance than steel, but its compressive strength is comparable to low- and medium-carbon steel.
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Malleable iron starts as a white iron casting that is then heat treated at about 900 °C (1,650 °F). Graphite separates out much more slowly in this case, so that surface tension has time to form it into spheroidal particles rather than flakes. …High-chromium white iron alloys allow massive castings (for example, a 10-tonne impeller) to be sand cast, i.e., a high cooling rate is not required, as well as providing impressive abrasion resistance.[citation needed] These high-chromium alloys attribute their superior hardness to the presence of chromium carbides.
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A more recent development is nodular or ductile cast iron. Tiny amounts of magnesium or cerium added to these alloys slow down the growth of graphite precipitates by bonding to the edges of the graphite planes. Along with careful control of other elements and timing, this allows the carbon to separate as spheroidal particles as the material solidifies. The properties are similar to malleable iron, but parts can be cast with larger sections.
https://en.wikipedia.org/wiki/Cast_iron

Wear resistance of chromium cast iron
– research and application
http://www.journalamme.org/papers_cams05/1184.pdf

Abrasion resistant cast iron materials are white, carbide-solidified cast iron materials which contain a high level of hard particles in the form of iron or chromium carbides. The carbides are held by a hard matrix. Generally the matrix is martensitic but there are also cases of an austenitic matrix as well, which only becomes more solid during the wear process associated with strain hardening. Since they are highly resistant to wearing, white cast iron materials are particularly suitable for applications involving wear caused by minerals, for example in grinding tools, in reducing, mixing and conveying equipment and systems and in pumps.
Abrasion resistant, white cast iron materials
DIN EN 12513, which was issued in January 2001, restructured the nomenclature of the varieties of abrasion resistant, white cast iron. This replaced the previously applicable DIN 1695, in which the chemical composition was still included in the name, as in the designation of steels. The designations in the new DIN EN 12513 are based on those for cast iron, with lamellar graphite or spheroidal graphite, in accordance with the described nomenclature for the GJN. The letter N indicates white, graphite-free solidification (“no graphite”). This is followed by the hardness specification, the minimum value of which is generally the most important factor affecting the choice of material. In this connection it should be noted that the hardness of white grades of cast iron is specified according to the Vickers method.
DIN EN 12513 differentiates between 3 classes of white, abrasion resistant cast iron: Unalloyed or low-alloyed, higher-alloy nickel and chromium cast iron and high-alloy chromium cast iron.
http://www.claasguss.de/html_e/pdf/THBl11_engl.pdf

EQUIAXED AND ORIENTED MICROSTRUCTURE IN HIGH CHROMIUM CAST IRON
Chromium cast iron is the material well-known and wide-ly used in numerous sectors of industry. From the data given in literature it follows that there are still various problems that occur during manufacture of this material and have not been properly solved until the present day [1-15].
http://www.imim.pl/files/archiwum/Vol2_2014/47.pdf
(Note: As no composition or other hint is given, to determine the chromium amount, we should refrain from specifying “high-chromium”.

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Note added at 16 hrs (2015-09-04 09:31:47 GMT)
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In order to determine the kind of cast iron I add the standardized european designations:

Désignation normalisée
La norme européenne EN 1560 indique :
• le préfixe EN-GJ, indiquant qu'il s'agit de fonte ;
• la famille de fonte :
o L : fonte à graphite lamellaire (fonte grise),
o S : fonte à graphite sphéroïdal (fonte grise),
o MB : fonte à cœur noir, fonte blanche malléable,
o MW : fonte à cœur blanc, fonte blanche malléable,
o N : fonte sans graphite,
o V : fonte vermiculaire,
o Y : fonte de structure spéciale ;
• la résistance à la rupture Rm, en MPa ;
• éventuellement l'allongement à la rupture A%.
L'ancienne norme française NF A 02-001 indiquait :
• la nature de la fonte :
o FB : fonte blanche, ou fonte à cémentite, de matrice martensitique,
o FGL : fonte à graphite lamellaire, ou fonte grise à graphite lamellaire,
o FGS : fonte à graphite sphéroïdal, ou fonte grise à graphite sphéroïdal,
o MB : fonte malléable à cœur blanc,
o MN : fonte malléable à cœur noir (structure ferritique) ;
• résistance à la rupture Rm en MPa ;
• éventuellement l’allongement à la rupture A en %.
P. ex. : EN-GJL-150 (anciennement FGL 150) : fonte à graphite lamellaire de résistance à la rupture Rm = 150 MPa
https://fr.wikipedia.org/wiki/Fonte_(métallurgie)

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Note added at 20 hrs (2015-09-04 12:58:57 GMT)
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La technologie N a révolutionné le pompage des eaux usées en apportant un fonctionnement hautement performant et autonettoyant, permettant ainsi de réduire le coût global d’exploitation. La technologie N modulaire vous offre la possibilité d'adapter sur mesure votre pompe, en choisissant parmi la fonte, la fonte au chrome ou le plateau dilacérateur, afin de répondre à votre besoin spécifique et obtenir un fonctionnement fiable. Ceci vous permet de réaliser des économies d'énergie significatives : jusqu'à 25 % d’électricité
http://www.XXXExperior.pdf

The innovative N-technology revolutionized wastewater pumping with sustained high efficiency and self-cleaning operation, thereby enabling lower total cost of ownership. N-technology gives you the option to customize your pump solution by choosing cast iron, hard-Iron™ or chopper hydraulics to meet your specific requirements for reliable operation. This enables you to achieve substantial energy savings up to 25% on your electricity bills.
http://www.XXXExperior.pdf
(Again, the client has its own terminology)

Conception flexible et modulaire La technologie N XXX vous permet de faire évolu - er la partie hydraulique afin de l’adapter à toutes les applications. Vous pouvez choisir la version en fonte trempée pour les applications des eaux usées traditionnel - les, la version fonte au chrome pour les applications abrasives et corrosives, et la version avec plateau dilacérateur pour couper les longues fibres ou les solides présents dans les eaux usés.
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Fonte au chrome (60 HRC) pour les défis les plus difficiles en pompage d’eaux usées
http://www.XXX

N-technology enables you to tailor the hydraulics to meet the requirements of virtually any application. Choose the hardened cast iron version for typical wastewater applications and the chopper ring version for cutting long fibers or solids. The Hard-Iron ™ version should be used in abrasive applications and waters that could cause erosion corrosion due to high oxygen content.
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hard-iron™(60 hrc) For the toughest wastewater challenges
http://www.XXX

If you are referring to impellers, I found several examples of Chrome cast iron impellers.