There are many types and styles of structural metal shapes used in the welding industry. Most weldments use combinations of these shapes. In reading prints, it is essential to know the shapes available and how their sizes are specified. The Appendix contains size specifications of common structural shapes.

As discussed in Unit 5, sheet metal is 3/іб" or less in thickness and plate is greater than 3/іб" thick. However, these measurements will vary slightly from manufacturer to manufacturer. Sheet thickness may be given as a fraction of an inch (usually as a decimal fraction) or as a gage number. Plate thickness is given as a common fraction of an inch.

A variety of standard gages is used to measure the thickness of various structural metal shapes. The most commonly used gage is the Manufacturer’s Standard Gage for Sheet Steel, formerly the U. S. Standard Sheet Metal Gage. Other common gages are the American Wire Gage (AWG) or Brown and Sharpe Wire Gage for sheets of brass, phosphor-bronze, aluminum, and German silver; and the Birmingham Wire Gage (BWG) for strip steel, steel bands, hoop steel, crucible spring sheet, and sheet copper.

Table 6.1 gives the standard gages used for wire, sheet, and plate. Note that several of the gages have more than one name.

Figure 6.1 illustrates a standard sheet metal gage. The openings along the cir­cumference are used to measure the thickness of sheet or plate, or the diam­eters of wire. The partial circles or holes in back of the openings are for clearance purposes only.

The size of the slot opening is indi­cated by a gage number placed near each slot on one side of the gage. The opposite side of the gage gives this size as a deci­mal fraction. Sheet metal thickness is of­ten specified with the gage used, the gage number, and its decimal size. This proce­dure is followed to reduce the possibility of error in the selection of the sheet.

The common method of specifying sheet and plate is to give the thickness (including gage used when it is sheet), width, and length in that order. The fol­lowing examples show how sheet and

plate sizes are specified. FIGURE 6.1 ■ Sheet metal and wire gage.

Thickness Width Length

Sheet No. 14 AWG (.0641) X 4' (or 48") X 6' (or 72")

Plate %" X 3' (or 36") X 8' (or 96")

Decimel Equivalents I
Gage No.	Birmingham Wire (BWG.) also Stubs Iron Wire		Brown and Sharpe or American Wire (AWG.)		Manufacturer's Standard Mfr's. Thickness for Steel		British Imp. Standard Wire (SWG.)		Stand. Steel Wire Gages or Washburn and Moen		Stubs Steel Wire		U. S. Standard (old)
7-0	—		—		—		.500		.4900		—		.5000
6-0	—		.5800		—		.464		.4615		—		.4687
5-0	.500		.5165		—		.432		.4305		—		.4375
4-0	.454		.4600		—		.400		.3938		—		.4062
3-0	.425		.4096		—		.372		.3625		—		.3750
2-0	.380		.3648		—		.348		.3310		—		.3437
0	.340		.3249		—		.324		.3065		—		.3125
1	.300		.2893		—		.300		.2830		.227		.2812
2	.284		.2576		—		.276		.2625		.219		.2656
3	.259		.2294		.2391		.252		.2437		.212		.2500
4	.238		.2043		.2242		.232		.2253		.207		.2344
5	.220		.1819		.2092		.212		.2070		.204		.2187
6	.203		.1620		.1943		.192		.1920		.201		.2031
7	.180		.1443		.1793		.176		.1770		.199		.1875
8	.165		.1285		.1644		.160		.1620		.197		.1719
9	.148		.1144		.1495		.144		.1483		.194		.1562
10	.134		.1019		.1345		.128		.1350		.191		.1406
11	.120		.0907		.1196		.116		.1205		.188		.1250
12	.109		.0808		.1046		.104		.1055		.185		.1094
13	.095		.0720		.0897		.092		.0915		.182		.0937
14	.083		.0641		.0747		.080		.0800		.180		.0781
15	.072		.0571		.0673		.072		.0720		.178		.0703
16	.065		.0508		.0598		.064		.0625		.175		.0625
17	.058		.0453		.0538		.056		.0540		.172		.0562
18	.049		.0403		.0478		.048		.0475		.168		.0500
19	.042		.0359		.0418		.040		.0410		.164		.0437
20	.035		.0320		.0359		.036		.0348		.161		.0375
21	.032		.0285		.0329		.032		.0317		.157		.0344
22	.028		.0253		.0299		.028		.0286		.155		.0312
23	.025		.0226		.0269		.024		.0258		.153		.0281
24	.022		.0201		.0239		.022		.0230		.151		.0250
25	.020		.0179		.0209		.020		.0204		.148		.0219
26	.018		.0159		.0179		.018		.0181		.146		.0187
27	.016		.0142		.0164		.016		.0173		.143		.0172
28	.014		.0126		.0149		.015		.0162		.139		.0156
29	.013		.0113		.0135		.014		.0150		.134		.0141
30	.012		.0100		.0120		.012		.0140		.127		.0125
31	.010		.0089		.0105		.012		.0132		.120		.0109
32	.009		.0080		.0097		.011		.0128		.115		.0102
33	.008		.0071		.0090		.010		.0118		.112		.0094
34	.007		.0063		.0082		.009		.0104		.110		.0086
35	.005		.0056		.0075		.008		.0095		.108		.0078
36	.004		.0050		.0067		.008		.0090		.106		.0070
37	—		.0045		.0064		.007		.0085		.103		.0066
38	—		.0040		.0060		.006		.0080		.101		.0062
39	—		.0035		—		.005		.0075		.099		—
40	—		.0031		—		.005		.0070		.097		—

Other forms of structural metals and the methods of specifying their sizes are presented in Table 6.2.

When considering size specifications, remember that steels are classified as hot-rolled or cold-rolled. Hot - rolled varieties are slightly oversized and have slightly rounded corners. Cold-rolled steels are more precise in size and have square corners. In addition, there are size specifications for certain structural shapes: S-beams (formerly called I-beams), H-beams, wide-flange (W) beams, and pipe are only approximate (nominal).

Structural Shape

Size Specifications

T x W x L (SYMBOL □ or 0) T = Thickness in inches W = Width in inches (same size as thickness for square bar) L = Length in feet and/or inches

NOTE: In machine shop practice, dimensions less than 72" are generally given in inches, and in feet and inches thereafter. In structural practice, dimensions of 12" and over are given in feet and inches.

1/2" x 1/2" x 18" 1/2" square x 18" 1/2" □ x 18" {Zf 1/2" x 18" 1/2" □ 18" long

Gage x W x L Gage (thickness) is expressed as a gage number or decimal fraction of an inch. W = Width in inches L = Length in feet or inches Expressed as: U. S. Std. Gage #7 x 36" x 96" or.179 Sheet x 3' x 8' or USSG #7 x 36" x 96"

T x W x L T = Thickness as a fraction of an inch (usually expressed as a decimal fraction) or a gage number (for strips 3/іб" thick and less). W = Width in inches (usually does not exceed 6") L = Length in feet and/or inches Expressed as: 1/8" x 2" x 8' or 1/8" x 2" x 8' long or.125" x 2" x 8'

SQUARE BAR

Expressed as: or or or or

RECTANGULAR BAR

T x W x L (SYMBOL = PL)

T = Thickness as a fraction of an inch or in decimals (1 /4" to 2" or.25" to 2")

W = Width in inches (usually does not exceed 6" for flat bar)

У x

Expressed as: 1/4" x 6" x 10'

10' long 10' PL

or

or.25" x

Weight is another specification applied to certain structural shapes and is often included with the size specifications. The weight is given because the cross-sectional areas of two similar shapes may vary although the overall sizes are the same.

Weight specifications are applied to channels, S-beams, M-beams, W-beams, and HP-beams. The specifica­tion is given in pounds per linear foot (lb/lin ft).

Structural Shape

Size Specifications

D x L (SYMBOL = О or0)

D = Diameter in inches (fraction or decimal) L = Length in feet and/or inches Expressed as: 1" round 8'6" long

or 1" О x 8*6"

ROUND BAR

or 0 1" x 8'6“

T x W x L

HALF OVAL BAR

T = Thickness in inches (fraction or decimal) W = Width in inches L = Length in feet and/or inches Expressed as: 1" x 2" half oval x 16' or 1" x 2" half oval 16'long

F x L (SYMBOL = HEX)

HEXAGON BAR

F = Distance across flats in inches (fraction or decimal) L = Length in feet and/or inches Expressed as: 3/4" HEX x 8" or 3/4" HEX 8" long or.750" HEX x 10'

F x L

F = Distance across flats in inches L = Length in feet and/or inches (fraction or decimal) Expressed as: 11/г" octagon x 10'

or 11/2" octagon 10'long or 1.500 octagon x 10'

angle x 18' x 18' -18' 18' long angle x 18' x 18' -18' 18' long

ANGLE IDENTIFIED BY THE SYMBOL Z

W x W x T x L W = Width of leg in inches T = Thickness of leg in inches L = Length in feet and/or inches Expressed as: equal legs 2" x 2" x 1/4" or 2" x 2" x 1/4" or Z2" x 2" x 1/4" or z.2" x 2" x 1 /4" Unequal legs or 2"x 1" x 3/іб" or 2"x 1" x 3/іб" or Z.2"x 1" x 3/іб" or Z.2" x 1" x 3/i6"

Size Specifications

Structural Shape

F x S x T x L TS x wt/ft x L

IDENTIFIED BY THE LETTER - T

F = Width of flange in inches

S = Width of stem in inches

T = Thickness of flange in inches

L = Length in feet and/or inches

WT = Tee cut from W-beam

MT = Tee cut from M-beam

HP = Tee cut from wide flange beam

Expressed as: or or

2" x 11/2" x V Tee x 18'

MT1V2"x3.12x 18' (3.12 represents pounds per linear ft)

WT18 x 150 x 18' long (150 represents pounds per linear ft)

or MT4 x 13 x 16' long (13 represents pounds per linear ft)

x F x T x L CD x wt/ft x L

D = Depth of channel in inches

F = Width of flange in inches

T = Thickness of flange

W = Thickness of web

L = Length in inches and/or feet

С = Standard shape

MC = Miscellaneous shape

Expressed as: 3" x 1.410" x. 170 channel x 15'

C3" x 4.1 x 15' (4.1 represents pounds per linear ft)

MC6" x 12 x 14' (12 represents pounds per linear ft)

C12 x 6" x 14'

CHANNEL IDENTIFIED BY THE LETTERS - С OR - MC

or

or

or

IDENTIFIED BY THE LETTER - Z

D

W x D x W x T x L LD x wt/ft x L

W = Width of flange in inches

D = Depth of stem in inches

T = Thickness of flange

L = Length in feet and/or inches

Expressed as: 13/4" x 13/4n x 13/4" x 3/іб" Zee x 18'

or 1_13/4" x 13/4" x 13/4” x 3/i 6" x 18'

or 13/4" х13/4" X 13/4M X3/16" ~L X 18'

or 13/4" x13/4" x13/4" X3/16" ~L 18' long

or ~L13/4"x 13/4" x 2.8 x 18' (2.8 represents pounds per linear ft)

TABLE 6.2 ■ Size specifications for structural shapes. (continued)

Size Specifications

Structural Shape

STANDARD S-BEAM (I-BEAM) IDENTIFIED BY THE LETTER - S

D x L SD x wt/ft x L

D = Depth of beam in inches L = Length in feet and/or inches SD = S-beam depth LB WT/FT = Pounds per linear foot Expressed as: 4" S-beam x 6'

or 4" S x 6'

or 4" S x 8 x 6' (8 represents weight in pounds per

linear ft)

ALSO MISCELLANEOUS BEAM (M-BEAM) IDENTIFIED BY THE LETTER - M

or 4" S x 8 x 6' long

or S 4" x 8 x 6'

NOTE: Miscellaneous beams are expressed similarly except for the identifying letter (M).

D x F x wt/ft x L

WIDE-FLANGE BEAM IDENTIFIED BY THE LETTER - W MISCELLANEOUS AND HP BEAMS

D = Depth in inches

F = Width of flange in inches

L = Length in feet and/or inches

Expressed as: or or or or

24" x 8" W - beam

24" W - beam, 120 lb/ft x 20'

24" W 120, x 20' (120 represents weight in pounds per linear ft)

24" W beam

W 24" x 120x20'

ALSO BEARING BEAM (HP BEAM) IDENTIFIED BY THE LETTERS - HP

The same size specifications apply as for standard and wide - flange beams except for the beam identification letter(s).

For example: M4 x 13.0 x 10'

or HP14 x 117 x 10' long

NOTE: Bearing beams are expressed similarly except for the letter

designation (HP).

For Square Tubing

or or or or or or

, For Rectangular Tubing

--- w—J SQUARE AND RECTANGULAR TUBING

There are two basic types of hollow structural steel with square corners: square and rectangular. The size is determined by the width and the depth. W x D x T x L W = Width in inches D = Depth in inches T = Thickness in inches L = Length in feet and/or inches Expressed as: 1" x 1" x.125" sq. tubing x 10' 1" x 1" x.125" □ x 10' 1" x 1" x.125" sq. tubing, 10' long 2" x 11/4" x.083" x 8' Rectangular tubing 11/2" x 1" x 0.65" x 6" Rectangular tubing 2 x 11/2 x 11 gage x 12' long 11/2 x 3/4 x 14 x 10' (14 signifies gage size of.083") or 11/2" x 3/4" x 14 Ox 10'

Size Specifications

Structural Shape

PIPE ID FOR SIZES 12" AND LESS (SEAMLESS) (SEAMLESS)

There are three basic types of pipe. Nominal sizes for these types are determined by the inside diameter except when the diameter exceeds 12", in which case the size is determined by the outside diameter.

ID x L (12" D and test)

OD x L (over 12" D)

STANDARD PIPE IDENTIFIED BY THE WORD - PIPE

ID = Inside diameter in inches OD = Outside diameter in inches L = Length in inches and/or feet STD = Standard Nominal = Approximate size XS = Extra strong XXS = Double extra strong

Expressed as: 5" standard pipe x 8' (5" represents nominal ID size)

or 14" standard pipe x 8' (14" represents nominal OD size)

or 14" STD pipe x 8' long

or 5" extra strong pipe x 8‘ or pipe XS 5" x 8'

or 5" double extra strong pipe x 8'

or 5" XXS pipe x 8'

or 5" standard pipe 8' long or pipe 5" STD x 8'

There are two basic types of tubing: standard and thinwall. The size is always determined by the outside diameter and the wall thickness.

OD = Outside diameter in inches

T = Wall thickness in decimal fractions of an inch

L = Length in feet and/or inches

STD = Standard

Expressed as: 3" x .065" x 10', standard tubing or STD

tubing

or 3" x .024" x 10', thinwall

or 3" standard tubing x.065", 10' long

or 3" STD tubing x.065" x 10'

TABLE 6.2 ■ Size specifications for structural shapes. (concluded)