The Art of Welding. William Galvery
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Название: The Art of Welding
Автор: William Galvery
Издательство: Ingram
Жанр: Зарубежная деловая литература
isbn: 9780831191641
isbn:
•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.
Figure 2-6 Welders find that portable power saws and grinders come in handy
Figure 2-7 Bench grinders are one way to sharpen TIG electrodes before welding
What types of clamps are used in 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.
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.
Figure 2-9 A portable welding table is useful when working in remote locations.
Photo courtesy of Miller Electric.
What are the most common steel products used in welding?
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.
Fig.2-10 Common steel products used in welding projects
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 facilitates adding leveling jacks, adjustment members, and clamps.
•Bolts—These can be used for leveling jacks, axels, swivel points, and locating pins. Bolts can also be cut to provide just the threaded portion for threaded studs, or just the rod section.
•Allthread—This is rod stock threaded end-to-end and useful where clamping or positioning action is needed.
•Hinges—There are three main hinge designs:
•Leaf hinges for welding—These hinges are not plated and have no screw holes.
•Cylindrical weld hinges—These are made in a wide variety of sizes and can support heavy loads.
•Piano hinges—Provide continuous support along a door or cover.
•Casters and Wheels—These are better purchased than shop-made.
Cu = Copper Sn=Tin Zn = Zinc Al = Aluminum Si =Silicon
Cleaning Metals
Some welding processes are fairly tolerant of mill scale and small amounts of rust and paint, so it is possible to make good welds on most steel rolled goods—flats and shapes—as they come from the mill. However, the metal must not be greasy and for this reason most hollow products like pipe, tubing, and hollow rectangular shapes that are shipped from the factory well oiled must be degreased before welding.
Household cleaners like Simple Green® or Formula 409® All Purpose Cleaner will work; industrial degreasers like denatured alcohol and acetone can also be used. Paint stores, metal supply houses, hardware stores, and pool supply stores often carry phosphoric acid (dilute in 4 to 10 parts water). These stores may carry tri-sodium phosphate (TSP), also a good cleaner. Do not clean hollow steel shapes too far in advance of welding or they will rust. Do not use compressed air to dry them off as this will re-introduce oil contamination from the compressor. Use a plastic bristle brush or a stainless-steel brush since copper, brass, or aluminum brushes will contaminate the weld.
Thorough Prep Work
•Grind, wire brush with a grinder, use flap wheels, or emery cloth to remove all mill scale, rust, paint, and dirt and get down to fresh metal.
•Wipe cleaned weld area with alcohol or acetone to remove residual grease.
•Avoid СКАЧАТЬ