Calculation formula of section area of round steel bar and its weight scale

Formula for calculating the section area of round steel bar

To find the sectional area of a plane circle from its radius, S=π r² is 3.14×r×r = area ²

π is PI =3.14, and r is the radius of the circle

Examples:

The diameter of a steel bar is 35MM, seek its area?

A: 3.14 * 17.5 * 17.5

Area = 961.6252mm

---

Rebar specification theory weight scale

Dimensions, external weight and allowable deviation of hot-rolled bar (Round bar); Theoretical weight scale of specifications (GB/T14981-94)

Round steel theoretical weight scale

General specific gravity of steel:

• Chromium steel 15CrA 20Cr, 7.74
• Ordinary carbon steel Q195, Q215, Q235, Q255, Q275 7.85
• 05F, 08F, 15F 10, 15, 20, 25, 30, 35, 40, 45, 50 7.85
• Carbon tool steels T7, T8, T9, T10, T12, T13, T7A, T8A, T9A, T10A, T11A, T12A, T13A, T8MnA 7.85
• Silicon manganese steel 60Si2nMnA 7.85

Specifications of the diameter	The weight per meterkg/m	The diameter of	The weight per meterkg/m
5.5	0.186	13	1.04
6	0.222	14	1.21
6.5	0.26	15	1.39
7	0.302	16	1.58
8	0.395	17	1.78
9	0.499	18	2.0
10	0.617	19	2.23
11	0.746	20	2.47
12	0.888	21	2.72
22	2.98	63	24.5
23	3.26	65	26
24	3.55	68	28.5
25	3.85	70	30.2
26	4.17	75	34.7
27	4.49	80	39.5
28	4.83	85	44.5
29	5.18	90	49.9
30	5.55	95	55.6
31	5.92	100	61.7
32	6.31	105	68
33	6.71	110	74.6
34	7.13	115	81.5
35	7.55	120	88.8
36	7.99	125	96.3
38	8.9	130	104
40	9.86	140	121
42	10.9	150	139
45	12.5	160	158
48	14.2	170	178
50	15.4	180	200
53	17.3	190	223
55	18.6	200	247
56	19.3	220	298
58	20.7	250	385
60	22.2
Formula: Radius x radius x 3.14 x per meter x 0.785 For example: the diameter of 6.0 steel bar, (0.03×0.03×3.14)×100×0.785=0.221841 In parentheses is the cross-sectional area, 3.14 is PI, 100 is centimeters (per meter), 0.785 is the specific gravity per square centimeter, so all values are converted into uniform units for calculation

---

Rebar theoretical weight scale

Thermal Gadolinium reinforcement (rebar) specification theory weight scale for reinforced concrete complete/per meter
Type d0 (millimeter)	Inside diameter d (millimeter)	Outside diameter d1 (millimeter)	Theoretical weight (kg/m)
6	5.75	6.75	0.222
7	6.75	7.75	0.302
8	7.5	9.0	0.395
9	8.5	10.0	0.499
10	9.3	11.3	0.617
12	11	13.0	0.888
14	13	15.5	1.21
16	15	17.5	1.58
18	17	20.0	2.00
20	19	22.0	2.47
22	21	24.0	2.98
25	24	27.0	3.85
28	26.5	30.5	4.83
32	30.5	34.5	6.31
36	34.5	39.5	7.99
40	38.5	43.5	9.87

Source: China Steel Bar 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.)

If you want to have more information about the article or you want to share your opinion with us, contact us at [email protected]

Please notice that you might be interested in the other technical articles we’ve published:

• Why can’t gun barrel be produced by casting instead of being drilled out with iron bars
• Calculation formula of theoretical weight of hexagonal bar