180° Elbow

Size: 1/2"-48"
Wall thickness: SCH5S-SCHXXS
Material: Special Alloy, Super Duplex Stainless Steel, Stainless Steel, Carbon Steel, Titanium
Standards: ASME B16.9, ASME B16.28, MSS SP43, MSS SP75

INQUIRY

PRODUCT DETAIL
Material

Size: 1/2″-48″
Wall thickness: SCH5S-SCHXXS
Material: Special Alloy, Super Duplex Stainless Steel, Stainless Steel, Carbon Steel, Titanium
Standards: ASME B16.9, ASME B16.28, MSS SP43, MSS SP75

Table of Contents

A 180 degree elbow of stainless steel refers to the elbow product whose bending angle reaches 180 degrees. According to its curvature radius, it can be divided into long radius 180 degrees stainless steel elbow and short radius 180 degrees stainless steel elbow. The long radius refers to the outer diameter of the tube whose curvature radius is equal to 1.5 times, that is, R = 1.5D. Short radius elbow refers to its curvature radius equal to the outside diameter of the pipe, that is, R = 1.0D, (R is the radius, D is the diameter of the elbow). Of course, different 180 degree stainless steel elbows can also be customized according to different curvature radius.
In the pipeline system layout, it is generally appropriate to use long radius elbow connection, short radius elbow is usually used in the pipeline installation location is more compact occasions or in order to reduce costs. When using short radius elbow, its working pressure should not exceed 0.8 times of long radius elbow of the same specification.

BUTTWELD ELBOW 45/90/180 DEGREE

ASME B16.9 buttweld elbows are manufactured in a wide range of dimensions (combinations of outside diameter and wall thickness) to fit ASME B36.10 and ASME B36.19 carbon, alloy and stainless steel pipes of any size between 2 and 48 inches (and above).

Buttweld elbows below 24 inches in diameter are produced by cutting, heating and bending seamless steel pipes; pipe elbows of larger sizes are manufactured, instead, from welded pipes or steel plates.

The three most common types of elbows in piping are the 45, 90, and 180 degrees (or return elbow), as shown in the image:

Types of elbows in piping
Some special types of pipe elbows are:

reducing elbow: a pipe connector with an inlet and an outlet in two different bore sizes is used instead of the combination of a standard elbow and concentric reducer.
mitered elbow: large size elbow assembled by joining steel plates

reducing elbow

SHORT VS LONG RADIUS ELBOW

Elbows are split into two groups which define the distance over which they change direction; the center line of one end to the opposite face. This is known as the “center to face” distance and is equivalent to the radius through which the elbow is bent.
The center to face distance for a “long” radius elbow, abbreviated LR always is “1.1/2 x Nominal Pipe Size (NPS) (1.1/2D)”, while the center to face distance for a “short” radius elbow, abbreviated SR even is to nominal pipe size.

Here below, for example, you will find the
center to face distance of NPS 2 elbows
(the A distance on the image)

90°-LR : = 1.1/2 x 2(NPS) x 25.4 A=76.2 mm
180°-LR : = 2 times the 90° LR elbow A=152.4 mm
90°-SR : = 2(NPS) x 25.4 A=50.8 mm
180°-SR : = 2 times the 90° SR elbow A=101.6 mm

3D elbows as an example, are calculated with:
3(D) X 2(NPS) X 25.4

PIPE ELBOW MANUFACTURING PROCESS

Buttweld elbows 180 degrees can be manufactured in different ways, the main ones are the “mandrel process” and the “cold forming” (other methods are the elliptical forming and the double-seam welding method).

Mandrel Process

Pipe Elbow Manufcturing Process (Mandrel Process)

Cold forming

Elbow manufacturing process (Cold forming method)

Elliptical Forming

Elliptical Forming

Two Seam Welding Method

Two Seam Welding Method

Quality Control
We have our own Physical & Chemical Testing Center Lab to guarantee our product quality. Our test items & instrument fully meet international standards.

Charpy impact test	Corrosion test	PT penetration inspection	Tensile test
Ultrasonic wt testing	Hardness test	Dimension test	High test
Thickness test	Alloy Analyzer (PMI)

Application of 180° Elbow

Pipe and Tubes for petrochemical industry
Pharmaceutical industry
Food industry
Aviation and aerospace industry
Architectural decoration industry
Oil and Gas Pipeline industry

Dimensions Butt Weld Elbows 180° LR and SR ASME B16.9

NPS	O.D. D	180° Long Rad		180° Short Rad
NPS	O.D. D	Center to Center O	Back to Face K	Center to Center O	Back to Face K
1/2	21.3	76	48
3/4	26.7	76	51
1	33.4	76	56	51	41
1.1/4	42.2	95	70	64	52
1.1/2	48.3	114	83	76	62
2	60.3	152	106	102	81
2.1/2	73	190	132	127	100
3	88.9	229	159	152	121
3.1/2	101.6	267	184	178	140
4	114.3	305	210	203	159
5	141.3	381	262	254	197

NPS	O.D. D	180° Long Rad		180° Short Rad
NPS	O.D. D	Center to Center O	Back to Face K	Center to Center O	Back to Face K
6	168.3	457	313	305	237
8	219.1	610	414	406	313
10	273	762	518	508	391
12	323.8	914	619	610	467
14	355.6	1067	711	711	533
16	406.4	1219	813	813	610
18	457	1372	914	914	686
20	508	1524	1016	1016	762
22	559	1676	1118	1118	838
24	610	1829	1219	1219	914

Dimensions are in millimeters unless otherwise indicated. Wall thickness (t) must be specified by customer.

DIMENSIONAL TOLERANCES OF BUTT WELD ELBOWS 180° LR AND SR ASME B16.9

Nominal Pipe Size	1/2 to 2.1/2	3 to 3.1/2	4
Outside Diameter at Bevel (D)	+ 1.6 – 0.8	1.6	1.6
Inside Diameter at End	0.8	1.6	1.6
Center to Center (O)	6	6	6
Back to Face (K)	6	6	6
Nominal Pipe Size	5 to 8	10 to 18	20 to 24
Outside Diameter at Bevel (D)	+ 2.4 – 1.6	+ 4 – 3.2	+ 6.4 – 4.8
Inside Diameter at End	1.6	3.2	4.8
Center to Center (O)	6	10	10
Back to Face (K)	6	6	6
Wall Thickness (t)	Not less than 87.5% of Nominal Wall Thickness

Dimensional tolerances are in millimeters unless otherwise indicated and are equal ± except as noted.

Note:
MSS SP-43 only covers stainless steel buttweld fittings made for use with Schedule 5S and 10S pipe and Stub Ends suitable for use with Schedule 40S pipe, as defined in ASME B36.19. The dimensions and dimensional tolerances defined in MSS SP-43 are substantially the same as those in ASME B16.9 specifications from NPS 1/2 – NPS 24. Except with regard to the outside diameter at the bevel.

Source: Werner Sölken