Seamless concentric and eccentric Reducers, to EN 10253 and ASME B16.9
At Nirotec, we manufacture seamless Reducers for industrial piping systems – in our own production facility in Unna. From standard dimensions in non-alloy steels to special designs in duplex, P91 or nickel alloys – compliant with standards, documented and delivered on time.
Manufacturing & Properties
Our Reducers are manufactured from seamless Pipes and, depending on material, dimensions and requirements, are cold- or hot-formed. The transition geometry is achieved using specially designed forming processes that ensure uniform wall thickness distribution and optimum flow characteristics. This is followed – depending on material and application – by heat treatment and machining.
Typical designs:
Concentric Reducer:
Symmetrical diameter reduction – for vertical lines and applications without venting or draining requirements.
Eccentric Reducer:
One-sided flush design – for horizontal lines, pump inlets and applications with venting or draining requirements.
Special designs:
- Project-specific lengths outside the standard
- Special diameter combinations to drawing
- Heavy-wall designs for high-pressure applications
Technical data
- Concentric and eccentric designs
- Various diameter combinations
- Wall thicknesses up to 100 mm
- Diameters up to 610 mm
- Special lengths and special geometries available to drawing
Standards & Codes
- EN 10253-2 / EN 10253-4 – Seamless pipe fittings (Europe)
- ASME B16.9 – Factory-Made Wrought Buttwelding Fittings
- EN 13480 – Metallic industrial piping
- AD 2000 – Pressure equipment (Germany)
- ASME B31.1 – Power Piping
- ASME B31.3 – Process Piping
- ASME B31.12 – Hydrogen Piping
- NORSOK M-630 – Offshore piping components
- KTA 3201 / RCC-M – Nuclear engineering
- Project-specific specifications and drawings on request

Materials & Standards
Our Reducers are manufactured from a wide range of industrial materials. Depending on application, temperature, pressure and corrosion requirements, we supply components from different material groups.
Further materials and project-specific material requirements on request.
Unalloyed & low-alloy steels:
P235GH / 1.0345
P265GH / 1.0425
P355GH / 1.0566
L360 / 1.0582 / API 5L X52
L415 / 1.8972 / API 5L X60
WPB / A234 WPB / Carbon Steel
WPHY70 / A860 WPHY70
Low-temperature steels:
WPL3 / A420 WPL3
WPL6 / A420 WPL6
LF2 / A350 LF2
P355NL2
P460NL2
10Ni14
12Ni14 / 1.5637
Heat-resistant steels:
16Mo3 / 1.5415
WP11 / P11 / 1.7335 / 13CrMo4-5
WP22 / P22 / 1.7380 / 10CrMo9-10
WP91 / P91 / 1.4903 / X10CrMoVNb9-1
WP92 / P92 / 1.4901 / X10CrWMoVNb9-2
X20 / 1.4922 / X20CrMoV11-1
WB36 / 1.6368 / 15NiCuMoNb5
Austenitic stainless steels:
304 / 1.4301 / X5CrNi18-10 / V2A
304L / 1.4307 / X2CrNi18-9 / TP304L / WP304L
316L / 1.4404 / X2CrNiMo17-12-2 / TP316L / WP316L / V4A
316Ti / 1.4571 / X6CrNiMoTi17-12-2 / TP316Ti / WP316Ti
321 / 1.4541 / X6CrNiTi18-10 / TP321 / WP321
347H / 1.4912 / X7CrNiNb18-10 / TP347H / WP347H
310S / 1.4845 / X8CrNi25-21 / TP310S / WP310S
Duplex & Super Duplex
Duplex / 1.4462 / X2CrNiMoN22-5-3 / UNS S31803 / F51
Super Duplex / 1.4410 / X2CrNiMoN25-7-4 / UNS S32750 / F53
Super Duplex / 1.4501 / X2CrNiMoCuWN25-7-4 / UNS S32760 / F55
254SMO / 1.4547 / X1CrNiMoCuN20-18-7 / UNS S31254
Alloy 926 / 1.4529 / X1NiCrMoCuN25-20-7 / UNS N08926
904L / 1.4539 / X1NiCrMoCu25-20-5 / UNS N08904
Nickel alloys:
Monel 400 / 2.4360 / UNS N04400
Alloy 625 / 2.4856 / UNS N06625 / Inconel 625
Alloy 825 / 2.4858 / UNS N08825 / Incoloy 825
Alloy C-276 / 2.4819 / UNS N10276 / Hastelloy C-276
Alloy 718 / 2.4668 / UNS N07718
Alloy 800H / 1.4876H / UNS N08810
Alloy C-22 / 2.4602 / UNS N06022 / Hastelloy C-22
Copper-nickel & special materials:
CuNi10Fe1.6Mn / C70600 / 90-10 CuNi
CuNi70/30 / C71500
Zirconium 702 / UNS R60702
Quality Testing & Documentation
Manufacturing and testing within the scope of our QM system to ISO 9001 and AD 2000. Typical testing services:
- Visual inspection
- Dimensional inspection and wall thickness measurement
- Non-destructive testing (UT, RT, PT, MT)
- Positive Material Identification (PMI)
- Hardness testing
- Ferrite measurement for duplex materials
- External inspections by TÜV, Bureau Veritas, DNV or customer inspectors
- Test certificates to EN 10204 (3.1 / 3.2)
- Project-specific ITPs with hold and witness points on request

Applications & Industries
In use worldwide
Pipe fittings such as Reducers, Elbows and Tees are among the key connecting elements in modern piping systems and are used in particular in energy, chemical and process plants.
Energy and Power Plant Facilities
Nuclear Technology
Hydrogen and Energy Infrastructure
Chemical and Process Industry
Refineries and Offshore Facilities
Apparatus and Mechanical Engineering
Looking for a special dimension or special material?
At Nirotec, we also manufacture Reducers outside the standard range – please contact our sales team directly.
