Casing Materials

CP offers metallic, solid plastic, plastic lined and ceramic lined pumps. A wide range of metals are available: stainless steel, duplex alloys, nickel and nickel-base alloys, titanium and titanium alloys. The choice of plastics includes PFA as lining material, (virgin or carbon-filled) PTFE and PVDF. Ceramic lined pumps are also available.

1. Stainless Steel

Stainless steel is used where both a certain resistance to corrosion and other of its many superior properties are required. Different grades and surface finishes are available to suit each particular application.

1.4581 (~316Ti): CP’s standard casting

GX5CrNiMoNb19-11-2
Rust- and acid-resistant, this austenitic stainless steel is often used for precision casting. Its niobium content is eight times the carbon content (C ≤ 0.07%), making it resistant to mineral acids. Because of its numerous advantageous properties, this is the standard material CP uses for all cast stainless steel pump casings.
CP models: MKP, ZMP

1.4404 (316L): CP’s low-carbon casting

X2CrNiMo17-12-2
With its good acid resistance, this austenitic stainless steel is used in mechanical components where high corrosion protection is essential. Its low carbon content (C content) also provides immunity to intergranular corrosion, even after welding. It is primarily used in the chemical, pharmaceutical, medical and prosthetics industries, as well as apparatus engineering, sewage plants and paper manufacturing.
CP models: MKP, ZMP

1.4404/1.4435 (316L): CP’s standard alloy

X2CrNiMo18-14-3
This austenitic stainless steel alloy is available with a defined δ ferrite content of ≤ 3%, ≤ 1% and ≤ 0.5%. Being extremely resistant to corrosion, it is widely used for production equipment in manufacturing chemical, biotechnology and pharmaceutical products and in pulp and textile mills.
CP models: MKP-Bio, MKPP, ZMP

1.4538/1.4539 (904L)

X1NiCrMoCu25-20-5
Salient characteristics of this special steel are a high molybdenum content, extremely low carbon content and the addition of copper. Pumps constructed from this material have excellent stability against pitting, stress corrosion cracking and intergranular corrosion, making them ideal for applications in industries such as chemical manufacturing.
CP models: MKP, MKP-Bio, MKPP, SZMK

1.4301/1.4306/1.4307 (304/304L)

X5CrNi18-10
This austenitic stainless chromium-nickel steel is resistant to corrosion and readily weldable, with good polishing and deep drawing properties. However, applications with acids need to be clarified from case to case, and it loses its resistance to intergranular corrosion after welding. It is mostly used in the crude oil, chemical, petrochemical and automotive industries.
CP models: MKP, MKP-Bio, MKPP, SZMK, ZMP

2. Duplex Alloys

These alloys combine the good properties of both chromium (ferritic) and chromium-nickel (austenitic) stainless steels.

1.4517 (A890)

G-X3CrNiMoCuN 26-6-3-3
This duplex steel has excellent general corrosion resistance. It is also highly resistant to localised corrosion, particularly pitting, crevice corrosion and stress corrosion cracking, and is largely immune to intergranular corrosion. After solution annealing, it is considered to be especially tough when exposed to cold temperatures.
CP models: MKP, MKP-S, MKTP, MKPP, SZMK, MKP-Bio, ZMP

1.4460 (329)

X3CrNiMoN27-5-2
This material combines very good mechanical properties with excellent corrosion resistance. It is also particularly suitable for use in acidic or chloride-containing environments and for applications with phosphoric or organic acids.
CP models: MKP, MKP-S, MKTP, MKPP, SZMK, MKP-Bio, ZMP

3. Nickel and Nickel-Base Alloys

Nickel is attacked very slowly by dilute acids, while it is rendered passive by concentrated oxidising acids, i.e. forming a protective film. Nickel-base alloys offer excellent corrosion resistance and stability, even at extremely high temperatures. Due to their special properties, these materials are typically used in the chemical industry.

2.4170

GNi95
This material is mainly used for pumping molten alkalis or high-purity alkalis that must not be contaminated with iron ions. It is also suitable for evaporation of alkalis.
CP models: MKP, MKP-S, MKTP, MKPP, SZMK, MKP-Bio, ZMP

2.4602 (Hastelloy® C-22)

NiCr21Mo14W
An extremely corrosion-resistant nickel-chromium-molybdenum-tungsten alloy, this material exhibits exceptional resistance to mixtures of oxidising and reducing acids.
CP models: MKP, MKP-S, MKTP, MKPP, SZMK, MKP-Bio, ZMP

2.4610 (Hastelloy® C-4)

NiMo16Cr16Ti
This material is very resistant to crevice corrosion, pitting and stress corrosion cracking, also withstanding attack by reducing acids and organic or inorganic chlorides.
CP models: MKP, MKP-S, MKTP, MKPP, SZMK, MKP-Bio, ZMP

2.4617 (Hastelloy® B-2/B-3)

NiMo28
This commercially pure alloy offers outstanding resistance to alkali hydroxides and organic mixtures, even at high temperatures. It is extremely resistant to boiling hydrochloric acid/hydrogen chloride and boiling sulphuric acid (up to a concentration of 60%). The material retains its strength and ductility at low temperatures.
CP models: MKP, MKP-S, MKTP, MKPP, SZMK, MKP-Bio, ZMP

2.4819 (Hastelloy® C-276)

NiMo16Cr15W
This nickel-molybdenum-chromium alloy with an addition of tungsten can be used in a wide range of severe environments as it withstands all types of corrosion. The high molybdenum content makes it especially resistant to pitting and crevice corrosion. In addition, its low carbon content minimises carbide precipitation during welding to maintain resistance to corrosion in heat-affected zones of welded joints.
CP models: MKP, MKP-S, MKTP, MKPP, SZMK, MKP-Bio, ZMP

4. Titanium and Titanium Alloys

Titanium and titanium alloys are particularly suitable for highly oxidising and strong chloride solutions and suspensions. Unlike other metallic materials of construction, titanium is completely resistant to such chemicals.

3.7034 (Grades 1–4)
3.7164 (Grade 5)
Other grades

These materials have very high tensile strength and toughness, even at extreme temperatures. In addition, they are lightweight and exceptionally corrosion-resistant. CP uses various titanium grades for its pump casings to meet each of our customers’ specific requirements.
CP models: MKP, MKP-S, MKTP, ZMP

5. Plastics

CP offers a choice of solid plastic and plastic lined pumps. When in contact with many acids, plastics are generally more corrosion-resistant than most grades of steel. What is more, they are less expensive than metal alloys for constructing equivalent pumps.

PFA lining

PFA (perfluoroalkoxy) has similar properties to PTFE (polytetrafluoroethylene). The difference from PTFE is that PFA is more easily formable by melt-processing and extrusion techniques. In comparison with similar materials, PFA offers the highest continuous service temperature (up to +260°C) while remaining creep-resistant and being extremely chemically stable.
Casing material
EN-GJS-400-18-LT
Ductile (malleable) iron: GGG 40.3
CP models: MKPL, MKPL-S, EB

Virgin PTFE

Virgin PTFE (pure polytetrafluoroethylene) is resistant to nearly all chemicals, even at elevated temperatures up to 100°C. It is extremely non-reactive and resistant to acids, partly because of the strength of carbon-fluorine bonds, and is consequently often used in contact with reactive and corrosive chemicals. PTFE also has the best sliding and non-stick properties of all plastics. As the material is physiologically inert, even at high temperatures, it is ideal for contact with food. PTFE is best known for its use in Teflon® coating of frying pans.
CP models: MSKP, MSKPP, MSKS

Carbon-filled PTFE

The addition of a carbon filler to PTFE (polytetrafluoroethylene) gives the modified PTFE even more compressive strength and hardness, volume and surface resistivity and excellent sliding and wear properties. The filler is customised exactly to meet the customer’s requirements.
CP models: MSKP, MSKPP, MSKS

PVDF

PVDF (polyvinylidene fluoride) also offers high chemical resistance. It is primarily used in applications requiring the highest purity, strength and resistance to solvents, acids, bases and heat. Compared to other plastics, PVDF has an easier melt process, also allowing it to be injected, compression moulded or welded.
CP models: MSKP, MSKPP, MSKS

6. Ceramic Lining

Engineering ceramics, also known as advanced, technical, industrial or structural ceramics, are used for high-tech products. Pumps lined with this type of ceramic material exhibit exceptional abrasion resistance, impact resistance, high-temperature and compressive strength, and outstanding corrosion resistance. This also makes them perfect for vacuum processes and for pumping abrasive products, aggressive media, solids-laden fluids or oils and adhesives. They even withstand heat and salt water. All wetted parts of the pumps are lined with ceramic.

Casing material
EN-GJS-400-18-LT
Ductile (malleable) iron: GGG 40.3
CP model: ET