SIEKMANN elbows
special. elbow. production.

Pipe elbows according to EN 10253, DIN 2605 or ASME B16.9

Siekmann has been offering seamless elbows made in Germany for decades. Our strength lies in the forming of thick-walled welded pipe elbows as well as in the area of special pipe elbows. As a manufacturer, we also keep a small stock of blanks. We can also offer you individual items at short notice. We also manufacture new products in small quantities and with very short production times.

Our delivery programme includes seamless pipe elbows with thick walls, special materials, special radii, bends with leg extensions. As well as pipe bends manufactured as 45, 90 or 180 degree bends (intermediate dimensions also possible). We are particularly specialised in the production of pipe elbows with full utilisation (type B) according to the standard EN 10253-2 or 10253-4 or part 2 according to DIN 2605. Our products are used in refineries, power stations, oil drilling platforms, heat exchangers, in mechanical engineering and in many other areas.

If you would like to buy elbows, please contact us. We’re here to help.

Delivery programme pipe elbows:

Outer diameter:14,0 mm – 219,1 mm
Wall thickness:1 mm to 50 mm, depending on outer diameter
Angles:15°, 30°, 45°, 90°, 180° and in between
Type:Type 2D, 3D, 5D, long radius (LR), short radius (SR) – further bending diameters can be found under bending diameter
Standards:EN10253 type A and B, DIN 2605 part 1 and 2, ASME B16.9, production according to customer specifications,
Tolerances:In general, we manufacture according to the common tolerances of the pipe elbow standards. However, it is often the case that we also manufacture elbows with narrower tolerances. In this case we have the possibility, for example, to produce the pipe bend with a bending diameter of +/- 1mm.

We supply seamless elbows made of carbon steel, high alloy steel or stainless steel. In addition, our extensive experience in heat treatment enables us to form a wide range of materials. By the way, you will find a list of materials in the materials section.

Our production is subject to strict quality controls. Dimensional checks are carried out during the manufacturing process. This enables us to detect faults all the earlier. Siekmann is monitored by TÜV Nord and is ISO9001:2015 certified. Because of this, we can guarantee continuous improvement.

What is a pipe bend?

A pipe bend is a pipe fitting that has the purpose of changing the direction of piping systems. There are different types of elbows. Sometimes they differ in outer diameter, wall thickness, bending diameter, angle and material. In addition, a distinction is made between welded pipe elbows made of half shells and pipe elbows made of seamless pipe. Elbows are used in power plant construction, mechanical engineering, heat exchanger and plant construction etc….

Portfolio

Materials for elbows

Over the years, we have been able to gather a wide range of experience in the field of tube forming. Carbon steels, high-alloy steels and stainless steels are among our processing materials. Below you will find a list of the materials from which we can manufacture elbows:

EN / DIN()

  • P235GHTC1/2 (St 35.8 I/ III), P265GH, S355J2H
  • 16Mo3 (15Mo3), 10CrMo9-10 (10CrMo910), 13CrMo4-5 (13CrMo44)
  • X11CrMo5, X11CrMo9-1, X20CrMOV11-1, X10CrMoVNb9-1, X10CrWMoVNb9-2, 7CrMoVTiB10-10
  • P215NL (TTST35N/V), 12Ni14 (10Ni14)
  • P355N (StE355), P355NH (WStE355), P355NL1 (TStE355), P355NL2
  • L290NB (StE 290.7), L360NB (StE 360.7)
  • 1.4301, 1.4306, 1.4362 (Lean Duplex), 1.4401, 1.4404, 1.4435, 1.4436, 1.4439, 1.4462 (Duplex), 1.4466 (Super Duplex), 1.4501, 1.4539, 1.4541, 1.4550, 1.4571 1.4841, 1.4878, , 1.4876, 1.4952, 1.4835, 1.4877, 1.4910

ASME

  • WPA, WPB, WPC, WP1, WP5, WP9, WP11, WP12, WP22, WP32/27, WP91, WP92, WP304, WP304 H, WP304L, WP310, WP316, WP316L, WP316TI, WP321, WP347, WP347H
  •  WPL 3, WPL6, X42, X52, WPHY52, WPHY60
  • S30815, S31000, S31050, S31500, S31726, S31803, S32760, N08904
  • Alloy 800H, DMV310N

Standards for fittings and pipe bends

EN 10253-2

This is the current standard for fittings for welding in unalloyed and alloyed ferritic steels with special test requirements. Several DIN standards for different fittings have been combined into one European standard. Furthermore, the pipe elbow part is decisive for us here. We deliver according to the types 2D, 3D, 5D and also many special radii in between. Furthermore, EN 10253-2 also includes a part for elbows with full utilisation (type B). “Type B” elbows have a significantly increased wall thickness on the inside of the elbow compared to the wall thickness at the welding ends, as the inside of the elbow is the most heavily stressed area of an elbow.

EN 10253-4

This standard deals with fittings for welding made of austenitic and austenitic-ferritic (duplex) steels with special test requirements. For the most part, this standard corresponds to EN 10253-2. In addition, however, there are some differences in bending radii compared to EN 10253-2. Our team will be happy to inform you about the differences.

DIN 2605

DIN 2605 is the former pipe bend standard that has now been replaced by EN10253. Here, different wall thicknesses apply to the elbows with full utilisation compared to the new standards. This standard is also not as comprehensive as EN10253 and only includes a section on elbows and no other fittings.

ASME B16.9

This standard contains all technical delivery conditions for fittings manufactured according to ASME standard. Among other things, here is also a part for the elbows. The wall thicknesses are given in “schedule” series and the outside diameters in inch dimensions.

Pipe bend type A – type B different

The EN10253-2 and EN10253-4 standards distinguish between two different types of elbows. These types are named differently in the current standards. EN10253-2 speaks here of type A and type B. In contrast, EN10253-4 refers to these types as type A and type B.

Pipe bend type A or design A:

The fittings have the same wall thickness at the weld ends as at the bend body. The strength against internal pressure is less than that of a pipe with the same outer diameter, the same wall thickness and the same material. For this reason, we also speak of elbows with a reduced degree of utilisation. The wall thickness on the entire fitting body, as well as on the pipe connection, must maintain a minimum wall thickness of -12.5% compared to the normal wall thickness.

Pipe bend type B or design B:

The fittings have an increased wall thickness on the inside of the bend body. The strength against internal pressure is the same as the pipe with the same outer diameter, wall thickness and material. For this reason, one also speaks of pipe bends with full utilisation. The wall thickness on the inside of the bend must be increased compared to the connection wall thickness. The required wall thickness is calculated with the help of a complex formula that takes into account the outer diameter, wall thickness and especially the bending diameter. As a result, pipe bends with a particularly narrow bending diameter have to comply with significantly increased wall thicknesses on the inside.

As an example:

Pipe bend 76.1 x 12.5 – 2D Bending diameter 126

Type A Wall thickness: 11.0 mm

Type B Wall thickness: 16.8 mm

Differences between the types of elbows

Pipe elbows can vary in outer diameter, wall thickness and bending diameter. The different standards specify so-called standard construction types for the bending diameters. This is intended to help designers with planning by standardising them. In EN and DIN there are the standard types 2D, 3D, 5D and 10D. The American standard ASME B16.9 uses the terms long radius and short radius. These are similar to the bending diameters of the EN and DIN standards. Long Radius is similar to construction type 3D and Short Radius is similar to 2D.

Nevertheless, the standards differ in some places. For example, a pipe elbow with an outer diameter of 101.6 mm as type 2D EN10253-2 has a bending diameter of 190.0 mm. However, the pipe elbow with the same dimensions as a short radius according to ASME B16.9 only has a bending diameter of 177.8 mm. This pipe elbow as type 5D has a bending diameter of 415.0 mm according to EN10253-2, whereas this is 410 mm according to EN10253-4 (for austenitic steels). So you should pay close attention here so that there is no confusion. Translated with www.DeepL.com/Translator (free version)

Pipe elbows with tighter tolerances on the bending diameter are often required. This is where SIEKMANN comes into play. Our manufacturing processes enable tolerances that are significantly more precise than the standards. For example, the tolerance on the bending diameter according to EN10253-2 is +/-7mm. We can supply elbows with a tolerance of +/- 1mm on the bending radius.

Table Differences between types 2D, 3D and 5D

The following table shows a comparison of the construction types (center to end) for the different standards. The information is without guarantee.

Außen
Durchmesser
2S altDIN 2 S neu2D EN-22D EN-4DIN 3 S3D EN-23D EN-4DIN 4 S DIN 5 S5D EN-25D EN-4
17.2--20--
2016162532.542.5
21.317.517.525252838283542.542.545
25212127.542.552.5
26.92425252529382947.557.557.557
30252533.55062.5
31.827.525355567.5
33.7302525283838386072.572.572
353030456075
3832.532.545456582.582.5
42.437.532323248484872.592.592.593
44.54040518097.5
48.342.538383857575785107.5109.5108
51454563.56392.5115122.5
54505072.597.5122.5
5752.552.57272102.5127.5130
60.355515151767676107.5135137.5135
63.557.557.582.5115142.5
706557.59292127.5160160
76.170636363959595140175175175
82.577.577.5107.5152.5190
88.982.5767676114114114165205207.5205
9587.587.5132.5175220
101.69595133.5133190237.5235
108100100142.5142.5200252.5253
114.3105102102102152152152220270270270
121112.5112.5170225282
127117.5117.5175235300
133125125181181250312.5311.5
139,7/141,3132.5127127127190190190270330330330
146137.5137.5205245342.5
152.4142.5142.5215287.5357.5
159150150216216300375375
165.1155155230310390
168.3155152152152229229229310390390390
177.8170170250342.5430
193.7180180270270455
219.1203203203203305305305515515510

Bending diameter

We also manufacture elbow dimensions outside the standard bending diameters 2D, 3D, 5D. Our well-positioned tool portfolio also allows us to offer many special dimensions in the range up to 219mm outer diameter.

The following table lists all bending diameters with which we have already produced elbows.

Please also ask for other bending diameters.

Outer diameterBending diameter D=
1040
1440
1632
182
2032 – 50 – 53
21,335 – 39 – 50 – 55 – 56 – 76 – 85 – 87 – 300
2276 – 90 – 220
2542 – 50 – 55 – 60 – 68 – 88 – 90 – 106 – 120 – 180
26,948 – 50 – 51 – 57,5 – 58 – 60 – 64 – 68 – 76 – 78 – 80 – 85 – 95 – 100 – 105 – 115 – 117 – 135 – 140 – 170 -200 – 380
2857 – 65 – 67 – 70 – 84 – 96
3050 – 58 – 67 – 68 – 70 – 75 – 90 – 100 – 110 – 125 – 136
31,88 – 50 – 55 – 60 – 65 – 70 – 71 – 73 – 76 – 78 – 80 – 90 – 100 – 110 – 120 – 127 – 135 – 160 – 200 – 210 – 225
3250 – 56 – 65
33,745 – 50 – 53 – 56 – 60 – 63 – 70 – 75 – 76 – 79 – 80 – 90 – 100 – 120 – 145 – 250 – 270 – 480
3551 – 76 – 90 – 90 – 93 – 120 – 150 – 200
3850 – 54 – 55 – 59 – 60 – 64 – 65 – 70 – 75 – 75,5 – 76 – 77 – 79 – 80 – 81 – 85 – 90 – 91 – 93 – 95 – 96 – 100 – 102,6 – 110 – 114 – 115 – 118 – 120 – 130 – 133 – 140 – 150 -160 – 165 – 166 – 170 – 186 – 198 – 226 – 290 – 380
4095 – 103 – 110 – 370
42,460 – 62 – 64 – 75 – 77 – 85 – 90 – 92 – 96 – 98 – 100 – 114 – 126 – 130 – 140 – 145 – 150 – 160 – 185 – 187 – 370
44,568 – 70 – 80 – 84,5 – 90 – 100 – 102 – 105 – 107 – 110 – 111 – 115 – 140 – 141 – 160 – 195 – 199 – 272
48,376 – 78 – 80 – 85 – 91 – 96 – 100 -102 – 114 – 120 – 150 -152,4 -160 -170 -200 -215 -219 -225 -230 -270 -498
5165 – 76 – 90 – 93 – 95 – 102 – 105 – 110 – 114 – 122 – 127 – 130 – 135 – 139,7 – 152,4 – 160 – 185 – 230 – 245
54100 – 108 – 145 – 195
5785 – 105 – 107 – 115 – 132 – 144 – 150 – 155 – 168 – 170 – 180 – 185 – 205 – 208 – 225 – 255
60,376,2 – 80 – 97,5 – 102 – 110 – 114,3 – 120 – 132 – 150 – 152 – 155 – 157 – 168 – 180 – 190 – 200 – 203 – 215 – 218 – 234 – 244 – 270 – 280 – 480 – 500 – 700 – 800
63,582,5 – 93 – 110 – 115 – 118 – 128 – 155 – 165 – 230 – 285 – 420
70100 – 110 – 125 – 130 – 150 – 161 – 184 – 188 – 190 – 255 – 323 – 330
73127 – 155
75190
76,1126 – 140 – 154 – 175 – 176 – 190 – 194 – 190 – 210 – 274 – 280 – 281 – 300 – 350
80157 – 218 – 320
82,5127 – 155 – 158 – 160 – 215 – 229 – 350 – 380
85233
88,9115 – 116 – 152 – 156 – 160 – 165 – 175 – 228 – 325 – 330 – 370 – 410
100266
101,6152 – 178 – 190 – 194 – 267 – 300 – 360 – 380 – 475
102252 – 500
106289
108200 – 203 – 285 – 400 – 500 – 505
114,3204 – 210 – 232 – 270- 304 – 440 – 540
121225 – 240 – 304 – 340 – 350 – 564
127215- 235 – 277 – 350 – 470 – 600
133250 – 362 – 500 – 625
139,7254 – 265* – 380 – 500* – 540* – 660*
152285* – 430*
159300* – 432*
168,3304* – 458*
177,8500*
193,7540*
219,1406* – 610*

* nur in 90° herstellbar

SIEKMANN GMBH & CO. KG

Manufacturer for special pipe bends!

For several decades we have specialised in the production of special pipe bends made of seamless pipe. Newly developed production processes, experienced employees and constant control at all stages of production guarantee the highest quality standard.

  • Special dimensions
  • Production of thick-walled pipe bends
  • Production also of small series
  • Wide range of materials to be processed – carbon steel / stainless steel
  • Very fast delivery times
  • Production of pipe bends with tight tolerances
  • Dimensional range also outside the standard dimensions

We have made it our business to supply elbows quickly, reliably and of the highest quality. A large selection of tools allows us to manufacture almost any pipe elbow in the dimension range between 14 mm and 219.1 mm – especially in the thick-walled range.

Get to know us on the following pages and feel free to contact us. We are pleased about your interest

If you have an enquiry or would like to contact us, please use the form below. You can also contact us directly. You will find the relevant contact person under the menu item “Contact”.

History

In 1907, the Siekmann company was founded as a village blacksmith’s shop. In the beginning, forged parts were produced for the local agriculture. From 1928, the first products for the heating sector were manufactured. The first pipe bends were successfully produced in 1940. A new production facility was built in Lohne in 1957. The first tests with thick-walled elbows were carried out in 1970. In 1987, the Siekmann company was re-established at the Bünde site. From 1992, production was switched to special pipe bends with thick walls. For this purpose, new production methods were developed which are decisive for today’s success. In the following years, new land was acquired and a new production hall was built. Translated with www.DeepL.com/Translator (free version)

References

  • Total S.A.
  • Siemens
  • Hitachi Power
  • Alstom Power
  • Exxon Mobil Production
  • Buhlmann Rohr-Fittings- Stahlhandel
  • STAROFIT Klose GmbH & Co. KG
  • ThyssenKrupp Schulte GmbH
  • RFF Rohr Flansch Fittings Handels GmbH
  • Oschatz GmbH
  • Stahl u. Plastic- Flanschen GmbH
  • BHR Engineering & Construction
  • Piping- Service Steuer Handelsges. mbH