The Art of Welding. William Galvery. Читать онлайн. Newlib. NEWLIB.NET

Автор: William Galvery
Издательство: Ingram
Серия:
Жанр произведения: Зарубежная деловая литература
Год издания: 0
isbn: 9780831191641
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chalk, also called soapstone

      •Ball point metal marker

      •Single center punch mark or a line of punch marks

      •White lead or silver lead pencil

      •Felt-tip pen

      •Aerosol spray paint

      •Scriber on bare metal

      •Scriber on layout fluid

      Use weldor’s chalk for marking rough dimensions or to indicate cutting lines that will hold up under cutting torch heat. A line of center punch marks can be more accurate and will also withstand torch heat. For very accurate layout lines, spray paint the metal in the area of the layout lines and use a scriber to scratch through the paint to make the layout lines. Alternatively, machinist’s layout fluid (Dykem® is the major brand, and available in red or blue) can be used to make the scribed lines more visible. These lines will not hold up under torch heat, but can be essential to laying out non-torch cutting lines. A black felt-tip pen can also be used in place of spray paint or layout fluid to darken the metal and show up scriber lines. Do not use scribe marks to designate bend/fold lines since they will be stress raisers and the part will eventually fail along the scribed line. Metal markers are available. They put down a 1/16 inch width line, come in several colors, and are excellent for applying lettering to metals. The are rated at 700°F (370°C) so cannot be used for torch cutting lines. Note that some marking materials’ residues may contaminate GTAW welds.

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      Figure 2-3 This yellow marker is used for drawing layout lines

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      Figure 2-4 Soapstone applicators and refills mark metals. Soapstone is also called welder’s chalk

       Both Photos courtesy of Hobart Welders.

       Specialized Hand Tools

      Here are some tools most welders will find necessary. They include:

      •Chipping hammer to remove welding slag.

      •Wire brush for cleaning welds.

      •Hammer and cold chisel to break tack welds.

      •Pliers for moving hot metal safely.

      •Wire cutters to trim electrode wire.

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      Figure 2-5 Here is a group of specialized welder’s hand tools

       Photo courtesy of Hobart Welders.

      Many of the power tools used by welders are also used for carpentry and other tasks. They include:

      •Reciprocating saw—Excellent for rough cuts of bar stock, shapes, pipe, and plate.

      •Hand-held band saw—Capable of accurate cuts and following scribed lines; excellent for both pipe and tubing. Its throat is too small for most plate cutting.

      •Electric drill, drill bits—For starter holes to begin oxyfuel cutting, holes toinstall hardware, and for chain drilling.

      •Abrasive cutoff saw—Good for rod and pipe. Not good for shapes and tubing. Difficult to make accurate cuts.

      •Portable grinder with abrasive and wire wheels and abrasive flapwheels—To remove mill scale, rust, and paint before welding. It is also good for smoothing rough edges and removing bad welds.

      •Bench grinder/pedestal grinder with abrasive and wire wheels—Same as portable grinder, but here the operator holds the parts.

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      Figure 2-6 Welders find that portable power saws and grinders come in handy

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      Figure 2-7 Bench grinders are one way to sharpen TIG electrodes before welding

      Clamps play a critical role in holding the parts to be welded in the proper position to make the weld and in preventing weld-induced distortion. Welders use a variety of general purpose clamps and clamps specifically designed for welding projects.

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      Figure 2-8 This page shows a variety of clamps used in welding, including locking clamps in various shapes and sizes and common C clamps. The clamp shown directly above is an angle clamp; to the left is a group of magnetic clamps

       Photo courtesy of Hobart Welders.

       Welding Tables

      A welding table places the work at a comfortable height and allows weldors to concentrate on their work, rather than their discomfort. A welding table allows some welds to be made sitting down. Also, it provides a stable, flat surface to position and clamp work prior to welding. In some applications the work itself may be tack-welded to the table. Later these weld-tack beads can be ground off.

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       Figure 2-9 A portable welding table is useful when working in remote locations.

       Photo courtesy of Miller Electric.

      Low carbon, hot rolled solid shapes, sheet goods, plate, pipe, and tubing are the most often used fabrication materials. Large steel distributors stock a wide variety of shapes and sizes. Additional sizes and shapes of steel as well as other materials like alloy steels, stainless steel, brass, copper, and bronze are also available on order. These materials are substantially more expensive than carbon steel.

      When planning projects, remember that one size of tubing (either round, square, or rectangular) is dimensioned to telescope or slide smoothly into the next larger size. This can be very helpful and a design shortcut.

      Large steel distributors usually have a variety of remnant material that is sold by the pound. A tape measure and calipers can also help you determine if a particular remnant will be useful. This can be both economical and convenient for many projects. Bring work gloves to handle the greasy and sharp remnants.

      Usually for a small charge, or often at no charge, the distributor will cut the material to make it easier to transport since many products come in 20 foot lengths. With good planning, cuts made on the distributor’s huge shears or band saws can save you a lot of cutting time, particularly on heavy plate goods.

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      Fig.2-10 Common steel products used in welding projects

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       Other Hardware Items

      Common hardware items used by welders include

      •Nuts—By welding a nut over an existing hole, we can add threads without tapping them; this