What are elbows?

Pipe elbows are pipe fittings used to change the direction of pipes in a piping system. According to the angle, there are three most commonly used 45° elbow , 90° elbow and 180° elbow, according to engineering needs, but also includes other abnormal angle elbow, such as 60° elbow. The bending radius is less than or equal to 1.5 times the diameter of the elbow and greater than 1.5 times the diameter of the elbow. Elbow materials are cast iron, stainless steel, alloy steel, malleable iron, carbon steel, non-ferrous metals and plastics. Connection with the pipe are: direct welding (the most common way) flange connection, hot fusion connection, fusion welding connection, threaded connection and socket connection. According to the production process can be divided into: welding elbow, stamping elbow, push elbow, casting elbow, butt welding elbow.

Use of elbow

Connect two pipes with the same or different nominal diameters to make the pipe turn 90°, 45°, 180° and various degrees.

Because the elbow has good comprehensive performance, it is widely used in chemical engineering, construction, water supply, drainage, petroleum, light and heavy industry, refrigeration, sanitation, plumbing, fire protection, electric power, aerospace, shipbuilding and other basic projects.

• Wall thickness: SCH5 to SCH160
• Size range: 1/2 to 56 inches (DN 15 to DN 1,400mm)
• Degree: 22.5 Deg, 45 Deg, 90 Deg, 180 Deg
• Manufacturing standards: ANSI, ISO, JIS and DIN
• Process: butt welding, seamless
• Type: Long radius, Short radius, Large size
• Pressure: class 3000, 6000 and 9000

Types of pipe elbow

An elbow is a pipe fitting installed between two lengths of pipe or tubing to allow a change of direction, usually a 90° or 45° angle, though 22.5° elbows are also made. The ends may be machined for butt welding, threaded (usually female), or socketed, etc. When the two ends differ in size, the pipe fitting is called a reducing elbow or reducer elbow.

Short radius elbows	Long radius elbows
Stainless pipe elbows	Big diameter elbows

The degree types of short radius pipe elbows as below:

• 45 degree short radius elbow
• 90 degree Short Radius Elbow
• 180 degree short radius elbow

Elbows are categorized based on various design features as below:

• Long Radius (LR) Elbows – radius is 1.5 times the pipe diameter
• Short Radius (SR) Elbows – radius is 1.0 times the pipe diameter
• 90 Degree Elbow – where change in direction required is 90°
• 45 Degree Elbow – where change in direction required is 45°

A 90 degree elbow is also called a “90 bend” or “90 ell”. It is a fitting which is bent in such a way to produce 90 degree change in the direction of flow in the pipe. It used to change the direction in piping and is also sometimes called a “quarter bend”. A 90 degree elbow attaches readily to plastic, copper, cast iron, steel and lead. It can also attach to rubber with stainless steel clamps. It is available in many materials like silicone, rubber compounds, galvanized steel, etc. The main application of an elbow (90 degree) is to connect hoses to valves, water pressure pumps, and deck drains. These elbows can be made from tough nylon material or NPT thread.

Types of 90° elbows

90° elbows are manufactured as SR (Short Radius) elbows and LR (Long Radius) elbows: 
SR (Short Radius) Elbows:
These elbows have a Center-to-Face dimension of 1.0 X diameter. They are typically used in tight areas where clearance is the main issue.
LR (Long Radius) Elbows:
These elbows have a Center-to-Face dimension of 1.5 X diameter. They are the most common type of elbow and used when space is available and flow is more critical.

What is a 90 degree long radius elbow?

The 90 degree Long Radius Elbow manufactured using superior grade raw materials. The 90 degree Long Radius Elbows are used for connecting pipes of different diameters and find wide applications in various chemicals, construction industries, paper, cement & ship builders.

We have adopted advanced production equipment to make our 90 degree Short Radius Elbow(1D D711.2～D1219.2), which can not only improve product quality, but also save raw materials.

How to calculation weight of 90 degree long radius elbow?

Weight formula = 0.0387 * S( D – S ) * 1.5D/1000

• W = Weight (kg/piece).
• S = Thickness Schedule.
• D = Nominal Diameter.

ASME B16.9 Butt weld 90 degree Long Radius Elbow Dimensions

ASME B16.9 90°Short Radius Elbow Dimensional Tolerance

NPS	O.D. D	90 degrees Long Radius Center-to-End A	45 degrees Long Radius Center-to-End B	90 degrees 3D Center-to-End A	45 degrees 3D Center-to-End B
1/2	21.3	38	16	–	–
3/4	26.7	38	19	57	24
1	33.4	38	22	76	31
1¼	42.2	48	25	95	39
1½	48.3	57	29	114	47
2	60.3	76	35	152	63
2½	73	95	44	190	79
3	88.9	114	51	229	95
3½	101.6	133	57	267	111
4	114.3	152	64	305	127
5	141.3	190	79	381	157
6	168.3	229	95	457	189
8	219.1	305	127	610	252
10	273	381	159	762	316
12	323.8	457	190	914	378
14	355.6	533	222	1067	441
16	406.4	610	254	1219	505
18	457	686	286	1372	568
20	508	762	318	1524	632
22	559	838	343	1676	694
24	610	914	381	1829	757
26	660	991	406	1981	821
28	711	1067	438	2134	883
30	762	1143	470	2286	964
32	813	1219	502	2438	1010
34	864	1295	533	2591	1073
36	914	1372	565	2743	1135
38	965	1448	600	2896	1200
40	1016	1524	632	3048	1264
42	1067	1600	660	3200	1326
44	1118	1676	695	3353	1389
46	1168	1753	727	3505	1453
48	1219	1829	759	3658	1516

ASME B16.9 90° Long Radius Elbow Dimensional Tolerance

What is a 90 degree short radius elbow?

The 90 degree short radius elbow manufactured using superior grade raw materials. The 90 degree short radius elbows are used for connecting pipes of different diameters and find wide applications in various chemicals, construction industries, paper, cement & ship builders.

ASME B16.9 90 degree Short Radius Elbow Dimensional Tolerance

NPS	O.D. D	Center-to-End A
1	33.4	25
1¼	42.2	32
1½	48.3	38
2	60.3	51
2½	73	64
3	88.9	76
3½	101.6	89
4	114.3	102
5	141.3	127
6	168.3	152
8	219.1	203
10	273	254
12	323.8	305
14	355.6	356
16	406.4	406
18	457	457
20	508	508
22	559	559
24	610	610

ASME B16.9 90°Short Radius Elbow Dimensional Tolerance

What is a 45° elbow?

45° Pipe Elbow is also known as 45 “ells”. The 45° pipe elbow is used to connect tubes at a 45° pipe angle. As the name suggests, this is a pipe fitting device which is bent in such a way to produce 45° change in the direction of flow of the fluid/gas in the pipe.
Like a 90° elbow, the 45° pipe elbow also attaches readily to pipes of various materials like plastic, copper, cast iron, steel, lead, rubber etc. They are typically made as LR (Long Radius) elbows. These types of elbows are available in various sizes (in mm or inches). They are available with different male to female BSP thread connections. Providing a wide choice of colors, these 45° elbows can be manufactured to meet different specifications, in terms of size and diameter.

45 degree long radius elbow

The 45 degree long radius elbow manufactured using superior grade raw materials.

Butt weld 45 degree LOng Radius Elbow are used for connecting pipes of different diameters and find wide applications in various chemicals, construction industries, paper, cement & ship builders.

ASME B16.9 Butt weld 45 degree Long Radius Elbow Dimensions

NPS	O.D. D	90 degrees Long Radius Center-to-End A	45 degrees Long Radius Center-to-End B	90 degrees 3D Center-to-End A	45 degrees 3D Center-to-End B
1/2	21.3	38	16	–	–
3/4	26.7	38	19	57	24
1	33.4	38	22	76	31
1¼	42.2	48	25	95	39
1½	48.3	57	29	114	47
2	60.3	76	35	152	63
2½	73	95	44	190	79
3	88.9	114	51	229	95
3½	101.6	133	57	267	111
4	114.3	152	64	305	127
5	141.3	190	79	381	157
6	168.3	229	95	457	189
8	219.1	305	127	610	252
10	273	381	159	762	316
12	323.8	457	190	914	378
14	355.6	533	222	1067	441
16	406.4	610	254	1219	505
18	457	686	286	1372	568
20	508	762	318	1524	632
22	559	838	343	1676	694
24	610	914	381	1829	757
26	660	991	406	1981	821
28	711	1067	438	2134	883
30	762	1143	470	2286	964
32	813	1219	502	2438	1010
34	864	1295	533	2591	1073
36	914	1372	565	2743	1135
38	965	1448	600	2896	1200
40	1016	1524	632	3048	1264
42	1067	1600	660	3200	1326
44	1118	1676	695	3353	1389
46	1168	1753	727	3505	1453
48	1219	1829	759	3658	1516

ASME B16.9 45° Long Radius Elbow Dimensional Tolerance

The 180 degree Short radius Elbow manufactured using superior grade raw materials. The 180 degree Short radius Elbows are used for connecting pipes of different diameters and find wide applications in various chemicals, construction industries, paper, cement & ship builders.

45 degree SR elbow

The 45 degree short radius elbow manufactured using superior grade raw materials. Butt weld 45 degree short radius elbow are used for connecting pipes of different diameters and find wide applications in various chemicals, construction industries, paper, cement & ship builders.

ASME B16.9 Butt weld 45 degree Short Radius Elbow Dimensions

Nom.  Pipe  Size	Pipe  Sched.  or No.	Center-  to-end  Dimen.	Outside  Dia.	Inside  Dia.	Wall  Thick.	Approx.  Weight  (lb.)
		F	OD	ID	T
STANDARD WEIGHT
1/2	40	5/8	0.840	0.622	0.109	0.1
3/4	40	7/16	1.050	0.824	0.113	0.1
1	40	7/8	1.315	1.049	0.133	0.2
1 1/4	40	1	1.660	1.380	0.140	0.4
1 1/2	40	1 1/8	1.900	1.610	0.145	0.5
2	40	1 3/8	2.375	2.067	0.154	0.9
2 1/2	40	1 3/4	2.875	2.469	0.203	1.5
3	40	2	3.500	3.068	0.216	2.5
3 1/2	40	2 1/4	4.000	3.548	0.226	3.5
4	40	2 1/2	4.500	4.026	0.237	4.8
5	40	3 1/8	5.563	5.047	0.258	7.8
6	40	3 3/4	6.625	6.065	0.280	12
8	40	5	8.625	7.981	0.322	23
10	40	6 1/4	10.750	10.020	0.365	42
12	–	7 1/2	12.750	12.000	0.375	61
14	30	8 3/4	14.000	13.250	0.375	79
16	30	10	16.000	15.250	0.375	103
18	–	11 1/4	18.000	17.250	0.375	132
20	20	12 1/2	20.000	19.250	0.375	160
22	20	13 1/2	22.000	21.250	0.375	195
24	20	15	24.000	23.250	0.375	238
EXTRA STRONG
Nom.  Pipe  Size	Pipe  Sched.  or No.	Center-  to-end  Dimen.	Outside  Dia.	Inside  Dia.	Wall  Thick.	Approx.  Weight  (lb.)
		F	OD	ID	T
1/2	80	5/8	0.840	0.546	0.147	0.2
3/4	80	7/16	1.050	0.742	0.154	0.3
1	80	7/8	1.315	0.957	0.179	0.4
1 1/4	80	1	1.660	1.278	0.191	0.5
1 1/2	80	1 1/8	1.900	1.500	0.200	0.6
2	80	1 3/8	2.375	1.939	0.218	1.1
2 1/2	80	1 3/4	2.875	2.323	0.276	2.1
3	80	2	3.500	2.900	0.300	3.5
3 1/2	80	2 1/4	4.000	3.364	0.318	4.8
4	80	2 1/2	4.500	3.826	0.337	6.5
5	80	3 1/8	5.563	4.813	0.375	11
6	80	3 3/4	6.625	5.761	0.432	18
8	80	5	8.625	7.625	0.500	35
10	60	6 1/4	10.750	9.750	0.500	56
12	–	7 1/2	12.750	11.750	0.500	80
14	–	8 3/4	14.000	13.000	0.500	100
16	40	10	16.000	15.000	0.500	131
18	–	11 1/4	18.000	17.000	0.500	172
20	30	12 1/2	20.000	19.000	0.500	210
22	30	13 1/2	22.000	21.000	0.500	259
24	–	15	24.000	23.000	0.500	302

ANSI 16.9 tolerances – 45 degree short radius elbow

DIMENSIONAL TOLERANCES – ELBOWS
For all fittings				Elbows 90/45 deg	180° Returns
Nominal Pipe Size (NPS)	Outside Ø  at Bevel	Inside Ø  at End	Wall Thickness  t / t1	Center to End Dim. A-B-C-M	Center to Center Dim. O	Back to Face Dim. K	Align- ment of Ends U
1/2 a 2 1/2	1	0,8	Not	2	7	7	1
3 a 3 1/2	1	1,6	less	2	7	7	1
4	+2 -1	1,6	than	2	7	7	1
5 a 6	+3 -1	1,6	87,50%	2	7	7	1
8	2	1,6	of nominal	2	7	7	1
10	+4 -3	3,2	tickness	2	7	7	2
12 a 18	+4 -3	3,2		3	10	7	2
20 a 24	+6 -5	4,8		3	10	7	2
26 a 30	+7 -5	4,8		3	…..	…..	…..
32 a 48	+7 -5	4,8		5	…..	…..	…..

What is a 180 degree short radius elbow?

The 180 degree short radius elbow manufactured using superior grade raw materials. The 180 degree short radius elbows are used for connecting pipes of different diameters and find wide applications in various chemicals, construction industries, paper, cement & ship builders.

ASME B16.9 Butt weld 180 degree Short Radius Elbow Dimensions

ASME B16.9 180 degree Short radius Elbow Dimensional Tolerance

NPS	O.D. D	180° Short radius		180° Short Radius
		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
1¼	42.2	95	70	64	52
1½	48.3	114	83	76	62
2	60.3	152	106	102	81
2½	73	190	132	127	100
3	88.9	229	159	152	121
3½	101.6	267	184	178	140
4	114.3	305	210	203	159
5	141.3	381	262	254	197
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

ASME B16.9 180° Short Radius Elbow Dimensional Tolerance

For all fittings				180° Returns
Nominal Pipe Size (NPS)	Outside Ø  at Bevel	Inside Ø at End	Wall Thickness  t / t1	Center to Center Dim. O	Back to Face Dim. K	Align- ment of Ends U
1/2 a 2 1/2	1	0,8	Not	7	7	1
3 a 3 1/2	1	1,6	less	7	7	1
4	+2 -1	1,6	than	7	7	1
5 a 6	+3 -1	1,6	87,50%	7	7	1
8	2	1,6	of nominal	7	7	1
10	+4 -3	3,2	thickness	7	7	2
12 a 18	+4 -3	3,2		10	7	2
20 a 24	+6 -5	4,8		10	7	2
26 a 30	+7 -5	4,8		…..	…..	…..
32 a 48	+7 -5	4,8		…..	…..	…..

What is a 180 degree long eadius elbow?

The 180 degree long radius elbow manufactured using superior grade raw materials.

The 180 degree long radius elbows are used for connecting pipes of different diameters and find wide applications in various chemicals, construction industries, paper, cement & ship builders.

We have adopted advanced production equipment to make our 180 degree Long Radius Elbow(1D D711.2～D1219.2), which can not only improve product quality, but also save raw materials.

ASME B16.9 Butt weld 180 degree Long Radius Elbow Dimensions

NPS	O.D. D	180° Long Radius
		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
1¼	42.2	95	70
1½	48.3	114	83
2	60.3	152	106
2½	73	190	132
3	88.9	229	159
3½	101.6	267	184
4	114.3	305	210
5	141.3	381	262
6	168.3	457	313
8	219.1	610	414
10	273	762	518
12	323.8	914	619
14	355.6	1067	711
16	406.4	1219	813
18	457	1372	914
20	508	1524	1016
22	559	1676	1118
24	610	1829	1219

ASME B16.9 180° Long Radius Elbow Dimensional Tolerance

Most elbows are available in short radius or long radius variants.

SHORT RADIUS ELBOWS

The short radius elbows have a center-to-end distance equal to the Nominal Pipe Size (NPS) in inches, while the long radius is 1.5 times the NPS in inches. Short elbows are widely available, and are typically used in pressurized systems.

LONG RADIUS ELBOWS

Long elbows are typically used in low-pressure gravity-fed systems and other applications where low turbulence and minimum deposition of entrained solids are of concern.

What are forged pipe elbows?

Forged elbows are typically used to change the direction in the pipe and thus the direction of media flow. Forged socket weld fittings are limited to smaller pipe diameters (up to NPS 4, but usually NPS 2 or less) and are available in 3000, 6000 and 9000 pressure classes corresponding to Schedule 40, 80 and 160 pipes. Socket fittings are welded in place by fillet welds, which makes them weaker than butt-weld fittings, but still superior to threaded fittings for high-end projects.

• Pressure: 2000LBS, 3000LBS, 6000LBS, 9000LBS.
• Size: from 1/8″ to 4″.
• Material: ASTM A105, F304, F316, F304L, F316L, A182 F11/F22/F91.
• Connection ends: socket weld and threaded.

Threaded Pipe Fitting SS304 Precision Cast Fittings

Threaded Pipe Fitting SS304 with 90 degrees Elbow, Class 150lb, Male and Female Thread.

Size: 1/2 to 4 inch

304 90 degrees elbow, class 150lb, with male and female thread

Materials: SS304 and SS316

Manufacturing standards: ANSI, JIS, and DIN

Our prefessional foundry can do sand casting,lost wax casting and die casting.

The material as bellowing: 
Gray Iron, Ductile Iron, Steel, Stainless Steel, Malleable Iron and Alloy.
The products is widely used in automobile , machinery, pipe fittings, pump parts, valve part and other industry.

We are a group company consisting of:

• 4. Sand Casting Plants (mainly produce Cast Iron and Ductile Iron Products).
• 2. Resin Sand Casting Plants (mainly produce Cast Steel&Cast Iron Products).
• 3. Investment Casting Plants (mainly produce Stainless Steel and Carbon Steel products.

Manufacturing process of the pipe elbow

Mandrel method (Hot Forming)

• One of the most common Pipe Fittings Manufacturing Process for manufacturing Elbows Or Pipe Bends from the pipe is mandrel method which is kind of hot forming methods.
• In this method, the pipe is cut in pieces and push with the help of hydraulic ram. It is pushed over a die called “mandrel” which allows the pipe to expand and bend simultaneously.
• This method can be used to manufacture a wide range of the diameter of elbows or pipe bends.

• ELBOWS Or Pipe Bends Mandrel method.

Extrusion Method

In cold Extrusion method, a pipe with the same diameter as finished product is pushed through a die and formed into its desired shape. Usually applied to stainless steel small to medium sizes elbows or pipe bends.

Extrusion Method

UO Method

UO method is used to manufacture medium size of the elbow, tee, and reducers. The plate is cut out into a specially designed shape, it is formed first into a U-shape using a die and then into an O-shape or tubular form using another die, that is why this method is known as UO method. Once the pipe fittings formed in tumbler shaped it is welded from inside and outside of the closing seam. A cut plate is 1st from in U shape and then in O shape.

UO Method

Hot Forming Method

In a hot forming die bending method, a pipe is heated to forming temperature & formed in the die with the specific shape, this process may be repeated as needed to obtain the required shape, size and wall thickness. Usually applied to thick-wall items that cannot be bent on a mandrel die.

Hot Forming method for Elbow Manufacturing

Materials of elbows

• Carbon steel: ASTM/ASME A234 WPB-WPC
• Alloy steel: –WP 22-WP 5-WP 91-WP 911
  • ASTM A335 P22
  • ASME SA335 P91 elbow
  • ASTM A234 WP 11
• Low temperature steel: ASTM/ASME A402 WPL3-WPL6
• High performance steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70
• Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N
  • ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
  • ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H

Standards of elbows

• GB/T12459-2005 GB/T13401-2005 GB/T10752-2005 SH/T3408-1996 SH/T3409-1996
• SY/T0609-2006 SY/T0518-2002 SY/T0510-1998
• DL/T695-1999 GD2000 GD87-1101
• HG/T21635-1987 HG/T21631-1990
• ASME B16.9-2007 ASME B16.25-2007
• MSS SP 75-2008 MSS SP 43-2008
• CSA Z245.11-05-2005
• EN10253-1-1999 EN10253-2-2007 EN10253-3-2008 EN10253-4-2008
• DIN2605-1-1992 DIN2605-2-1995
• BS1640-1-1962 BS1640-2-1962 BS1640-3-1968 BS1640-4-1968 BS1965-1-1963
• AFNOR NF A 49-289-1990 AFNOR NF A 49-170-1-1999 AFNOR NF A 49-170-2-2009 AFNOR NF A 49-170-3-2009
• AFNOR NF A 49-170-4-2009 ISO3419-1981 ISO5251-1981
• JIS B2311-2009 JIS B2312-2009 JIS B2313-2009
• ASME B16.9 Butt weld 45 degree Long Radius Elbow Dimensions

Applications of pipe elbows

Various applications of pipe elbows are as follows:

• They are manufactured to be used in flow lines for gases, fluids in industrial processes, medical, construction and many other specialized applications.
• The elbows are constructed of heavy materials for rigid applications like extreme high/low temperature resistance etc.
• The elbows are specifically designed for use on process and control systems, instrumentation, and equipment used in chemical, petroleum, fluid power, electronic and pulp and paper plants. 

How to check the quality of elbow?

Whether the quality of elbow meets the requirements of technical standards is directly related to the quality of construction project and the operation safety of equipment. The construction site is the final acceptance and use link. Therefore, it is very necessary to adopt a scientific and feasible elbow detection method in the field.

Inspection of elbow

The elbow shall be subject to chemical composition analysis, mechanical property test and appearance and dimension inspection before delivery. For some elbow fittings with special requirements, low-temperature toughness impact testing, nondestructive testing, magnetic particle testing, etc. are also required. In order to avoid unnecessary rework or hidden danger to the operation of the device due to unqualified elbow quality, resulting in waste of human and material resources, loss of construction quality and extension of project construction period, the construction unit shall conduct on-site inspection before using elbow and other pipe fittings. This paper focuses on the detection method of elbow on the construction site.

Check of elbow

First, check the material grade of elbow, product code of elbow, standard number of elbow, standard size and wall thickness grade of elbow, and professionals use testing equipment to test and analyze the material of elbow. Generally, the chemical composition of the elbow shall be the same or similar to that of the welded pipe section, and shall be of the same steel grade, and the physical properties will not change or produce cracks and other defects due to reheating.

Appearance inspection of elbow

The inner and outer surfaces of the elbow shall be smooth and regular, and shall be free of defects such as crack, delamination, stutter, thinning, depression, sharp scratch, notch, folding, etc.

Geometric dimension inspection of elbow

The geometric dimension inspection is the work carried out by the pipeline installer after checking the elbow identification and elbow materials, and the appearance of the elbow has been visually inspected. It is the continuation of the appearance inspection. Since most construction sites do not have professional testing equipment, installation workers can only use ordinary tools such as level ruler, angle ruler, ruler, caliper, powder line and thickness gauge to carry out a series of inspections on bending, flatness, ovality, end groove, port perpendicularity, bending radius and thinning rate, so as to check whether the pipe fittings meet the requirements of the document and determine the blanking size of the pipe section, And eliminate the defects found, which requires pipeline installers to have high operation skills. Select flat ground or steel plate and place the elbow horizontally. Check repeatedly with a level ruler, adjust the height of different parts of the elbow, and plug gaskets under it until the middle and both ends of the elbow are horizontal. Use a square, level and steel ruler to find out the top, middle and bottom four bisection points of the two ends of the elbow, and connect the corresponding points respectively to obtain the inner arc, outer arc and two middle arcs. As shown in Figure 1.

Figure.1

• (1) Ovality detection: ovality, also known as out of roundness, is usually the diameter measurement of the same section in the vertical and horizontal directions. If the diameter is large, the measurement points must be added. During the measurement, the values of the two ends and the middle three sections shall be recorded respectively, and the two values of the same section shall be subtracted to ovality.
• (2) Detection of bending radius: take the outer arc point and inner arc point at both ends of the elbow as the reference point, lead two chalk lines to intersect at a point, and measure the distance between the point and the inner arc with a ruler or tape. The distance value plus the bending radius of the elbow ½ The outer diameter is the bending radius of the elbow. According to the specification, the bending radius measured at both ends of the elbow shall be equal, but the value may be different due to machining deviation. If any, the two halves of the elbow shall be calculated separately to ensure the accurate blanking of the pipe section. If there is a steel plate, you can also draw the standard inner arc of the elbow on the steel plate with a scribe gauge, and place the elbow on the steel plate so that the inner arc of the elbow coincides with the projection of the scribed arc, so that the required value can be measured on the steel plate. The measured values of the above two detection methods are easy to deviate due to the roundness of the elbow port, so the influence of ovality on the measurement should be considered in advance.
• (3) Detection of thinning rate: elbow thinning is generally local thinning, which mostly occurs at the outer arc. At present, the detection method of thinning rate is relatively simple. Use a portable thickness gauge to measure the wall thickness of the elbow at multiple points, and the thinning rate can be obtained by comparing the measured value with the standard value. There is little research on the detection method of elbow local thinning in the industry, and the current detection method is the same The possibility of missing inspection cannot be completely avoided. If the wall thickness difference between the elbow and the pipe section exceeds 2mm, the inner wall shall be thinned at 15 °.
• (4) Detection of bending degree: the detection method is basically similar to the detection method of bending radius. Use two long steel ruler or powder line to lead out and intersect at one point based on the inner and outer arc of the end face, and measure the bending degree with an angle ruler or protractor.
• (5) Detection of port perpendicularity: it is best to detect the perpendicularity on the steel plate. If there is no suitable steel plate due to conditions, you can use a ruler or find a straight pipe section flat on the top of the elbow as the reference line. One end of the square rests against the reference line and the other end is close to the elbow port for perpendicularity detection.
• (6) Groove and flatness detection: most seamless elbows are connected by welding. In order to ensure the welding quality, there are machine-made grooves at both ends, and the angle and the thickness of the blunt edge are strictly regulated, which can be measured with caliper. When checking the groove, the flatness of the surfaces at both ends must also be checked, and the flatness can be determined by clinging a flat wooden board or steel plate to the end face and checking the gap Whether the flatness deviation exceeds the standard.

What is the difference between an elbow and a bend?

Elbows and bends are fittings used to change the direction of pipes. These two kinds of pipe fittings have been widely used in buildings. However, in practical use, the performance of elbow and elbow is different. Let’s take a look at the difference between elbow and elbow.

Elbow is a kind of pipe fitting, an ordinary pipe fitting, which is usually manufactured according to specific needs. The length is much longer than the elbow. Although they are all fittings that change the direction of the pipe, there are still many differences between them. The most basic difference between bend and elbow is that elbow is relatively short compared with elbow. R = 1 to 2 times is the elbow, and the larger multiple is called the bend.

1. Different manufacturing processes
The essential difference between bend and elbow is mainly the difference between “head” and “pipe”. In addition, there are great differences in the production process. During the manufacture of elbows, pipes can be used for cold bending. Then bend it directly with a pipe bender. Elbows can be manufactured at one time without secondary corrosion protection, but they need to be customized by the manufacturer, which requires corrosion resistance and long service life.
2. Different prices
The price of elbow is lower than that of bend, but it is easy to be damaged without anti-corrosion protection. However, due to its low price, elbow has been widely used in some projects with low requirements.
3. Different bending radii
The bending radius of bend is usually larger than that of elbow; The mechanical strength per unit area of elbow is usually greater than that of elbow. In use, you can choose according to your needs. For example, to deal with the scour of pipeline fluid at the corner, thick wall elbow can be selected to achieve the purpose of erosion resistance; Large radius bend can also be used to reduce (disperse) scouring force.
4. Different scope of application
In a good construction enterprise environment, elbows and bends can be used. If we only consider the product cost, we choose cold bend. After all, the quality of hot bends is good, but the cost is high. In the process of building development, due to the convenience of engineering construction technology, elbow is more suitable for use in relatively narrow places. The specific construction working environment of the problem needs to be fully considered. Although they can also be used in narrow environments. However, some troubles are often encountered in practical use.
In fact, from the point of view of producing parts. The elbow is short. In the actual construction process, if you need to change the direction, you can choose which pipe fitting to use according to the specific construction conditions.
The above is the difference between elbow and elbow. We hope that through these contents, we can better understand elbows and bends for you. During the construction process, you can also make reasonable choices based on the analysis of the actual development of the company. Elbow and bend are two different pipe components, so they can better complete the construction and improve the construction quality.

Source: China Pipe Elbows Manufacturer – Yaang Pipe Industry Co., Limited (www.epowermetals.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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