Calculation of butt weld elbow weight

Butt Weld Fittings

The Butt Weld Elbow is a basic fitting for changing the direction of water, gas and oil pipelines. It is important to get the approximate weight which determines the cost. So how to calculate the weight of the elbow in kg?

What Factors Influence Butt Weld Elbow Weight?

To know the weight of the elbow, we should know what factors determine the weight.

Many factors affect its weight, the most influential factors are diameter, wall thickness, radius and elbow degree.

Next, I will show you how to calculate the weight based on these factors.

How to Calculate 90 Degree Elbow Weight?

People mainly use two ways to calculate the butt weld pipe fittings.

Calculate by weight formula.

Get the value from the weight table.

No matter which way you choose, the butt weld elbow weight is calculated based on 90 degree. Because 90 degree carbon steel elbow is the most common type.

Calculate 90 Degree Steel Elbow by Formula

This method is a bit difficult because we need to know some exact values in mm. They are outside diameter, wall thickness and bend radius. Unfortunately, this is not the unit we usually use to measure.

The formula of butt weld elbow or bend as below:

W=0.387 * S*(D – S) * R / 1000

Note:

• W means Weight. The unit is Kg/piece.
• S refers to wall thickness schedule.
• D is nominal diameter.
• R is Bend Radius. LR=1.5D, SR=1D.

For example, 1 inch 90 Degree LR Elbow Sch40 A234 WPB, From above information, we can get LR=1.5D, D=33.4mm, S=3.38mm, W = 0.387 * 3.38 * (33.4 – 3.38) * 1.5 * 33.4 / 1000 = 1.97. So it is 1.97 Kg per piece.

This formula is suitable for steel pipe bend as well.

Calculate 90 Degree Steel Pipe Elbow by Chart

Compared to formula, calculation by weight chart is a quick and easy way, which is very useful in practice, the things you need to do is find the value according to elbow dimensions. But we still use formula because it can be used for special thickness that we can’t find in the chart.

This chart are made based on Carbon Steel 90 Degree Long Radius Butt Weld Elbow Fittings, but it is also suitable for Stainless Steel and Alloy Steel Pipe in views of they are little different in weight. 45 degree steel elbow is calculated in the same way as formula, and short radius elbow is calculated by a simple multiplication.

90 Degree Long Radius Butt Weld Elbow Weight in kg

DN	NPS	10S	20	STD	40	XS	80	100	120	140	160	XXS
15	1/2	0.06		0.08	0.08	0.1	0.1
20	3/4	0.08		0.11	0.11	0.13	0.13
25	1	0.13		0.15	0.15	0.21	0.21				0.25	0.26
32	1 1/4	0.21		0.25	0.25	0.36	0.36				0.42	0.64
40	1 1/2	0.3		0.39	0.39	0.52	0.52				0.65	0.93
50	2	0.47		0.66	0.66	0.96	0.96				1.33	1.61
65	2 1/2	0.79		1.37	1.37	1.8	1.8				2.33	3.43
80	3	1.16		2.19	2.19	2.87	2.87				3.83	5.25
90	3 1/2	1.55		2.96	2.96	4.06	4.06
100	4	2.02		4.13	4.13	5.6	5.6				8.03	10.2
125	5	3.46		6.89	6.89	9.62	9.62				14.7	17.6
150	6	4.98		10.7	10.7	16.5	16.5		19.5		24.2	23.1
200	8	9.57	16.5	21.6	21.6	31.6	31.6	36.3	43.3	48.3	53.3	51.7
250	10	16.7	25.8	37	37	49.9	60.7	68.6	79.5	92.8	103	92.8
300	12	25.9	36.1	56	61	71.6	97.4	115	134	149	171	134
350	14	34.7	60.2	71.4	85.1	92	139	163	188	212	236
400	16	45.4	78	93.6	121	121	200	235	274	319	350
450	18	56.2	87.7	119	176	153	287	334	392		440	495
500	20	82.2	147	147	232	190	396	457	528	609	676
550	22	99.6	178	178		230	515	594	694	790	886
600	24	136	212	212	377	275	635	786	919	1033	1160

90 Degree Short Radius Elbow Formulas

• 90 Degree Short Elbow = 90 Degree Long Butt Weld Elbow * 0.9
• W=0.387 * S*(D – S) * R / 1000

For example, you have a DN100 Sch10S 90 Degree Long Radius A312 Gr.316 Elbow, according to the following chart, its weight is 2.02 Kg.

45 Degree Elbow Formulas

• 90 Degree Short Elbow Weight = 90 Degree Butt Werld Elbow Weight * 0.56

So the 45 degree elbow in above same size is 2.02 * 0.56 = 1.13 Kg.