Volume 16 - Machining Part 14 pps

Band sawing differs from the other sawing methods in that its blade and cutting action allow the cutting edge to follow a contoured path during cutting. When compared to other machining methods (milling, for example), contour cutting with a band saw has advantages such as: • Unwanted material is removed in sections instead of chips • Downward cutting action (vertical band saws only) holds work to the table, thus simplifying fixturing • Narrower tooth kerf minimizes power requirements for cutting and the amount of material reduced to chips Contour band sawing is performed on a vertical band saw having a C-shaped, open-yoke frame. Because of the open- yoke frame, clearance between the workpiece and the frame imposes a size limitation in contour band sawing. Workpiece height or thickness can be as much as 1400 mm (55 in.), which is the maximum capacity between the guides of standard machines. However, special machines have been built with yoke heights up to 3000 mm (120 in.). Convex radii of less than 1.6 mm ( in.) can be cut in a single pass using commercially available bands, thus making it possible to produce complex contours in one straightforward machining operation. To produce internal contours, the ends of the saw band are welded together after the band has been inserted through a hole provided in the workpiece for this purpose. The dimensional tolerances that can be maintained in contour and cutoff band sawing depend greatly on the dexterity of the operator, the suitability of the setup, tooling and machining conditions, and the availability of accessories, such as servo controls. Automated band saws have error control devices that can assure the accuracy of cut. If the blade cuts beyond the given tolerance of the programmed shape of the cut, then the machine shuts off, indicating the need for a blade change. In cutoff band sawing, cutting accuracy (straightness of cut) is usually within 0.002 mm/mm (0.002 in./in.). Contouring. A servo-controlled contour sawing attachment maintains a constant feed force and, by lessening the effort required, permits the operator to concentrate more fully on following the line to be cut, thus increasing overall accuracy. Under optimum conditions, a skillful operator with the aid of a magnifying glass can follow a contour to within ±0.25 or ±0.38 mm (±0.010 or ±0.015 in.). A tolerance of ±0.8 mm (± in.) is more typical of production work. When using a power table for ordinary work thicknesses, the flatness of the cut surface can be held to 0.004 mm/mm (0.004 in./in.) of work thickness or per 25 mm (1 in.) of cut length. Surface finish also varies with operator skill, equipment, and operating conditions. A surface roughness of 5.0 to 7.6 m (200 to 300 in.) results under ordinary production conditions. With the use of a fine-pitch blade, high band speed, and low feed force, a finish of 1.5 to 5.0 m (60 to 200 in.) can be produced, and a surface roughness as low as 0.63 m (25 in.) has been obtained under specially controlled conditions. Types of Machines Most band saws are designed for either vertical or horizontal movement of the saw band, although some manufacturers offer combination vertical-horizontal band saws for light to medium-duty cutting. The band saws available include contour band saws, cutoff band saws, tilt-frame universal band saws, and plate band saws. Contour band saws are vertical machines with C-shaped, open-yoke frames. Although this equipment can perform cutoff operations, it is seldom used for this purpose. Cutoff operations are usually done on a horizontal machine. Contour band saws are available in a wide range of sizes and modifications. There are three general types: fixed table, power table, and radial arm. Fixed-Table and Power-Table Machines. With a fixed-table machine, the work must be fed by hand. Power-table machines, which are usually heavier than fixed-table machines, are equipped with a worktable that pushes the work into the saw band, thus relieving the operator of pushing or manual feeding. These machines have enough power to use high- speed steel bands, while fixed-table machines usually employ a lower cutting rate and carbon steel bands. Radial-arm machines are designed for handling large, heavy workpieces. The articulated structure of the equipment provides the capability for unlimited cutting within a crescent-shaped area. The machine shown in Fig. 1 has a cutting crescent area of 9.2 m 2 (99 ft 2 ) and consists of three major members, of which two are movable and the third is stationary. The two moving members an intermediate arm and a cutting yoke permit the cutting edge of the saw frame to move anywhere within the prescribed area, while the workpiece mounted on a worktable that can be raised or lowered remains stationary. The longest straight cuts that can be made on this machine are 530 mm (209 in.) across the crescent and 1500 mm (59 in.) to the depth of the crescent, as shown by the shaped portion of the cutting-area diagram in Fig. 1. Fig. 1 Radial- arm contour band sawing machine and shaded crescent showing the total area within which the cutting yoke can move. The workpiece, mounted on the adjustable worktable, remains stationary. Cutoff band saws cut horizontally or vertically, but in a straight line only. Cutting angle, however, is adjustable. In a cutoff band sawing machine, the saw band is twisted through carbide guides to bring the blade perpendicular to the surface of the worktable. Cutoff band saws range from machines used for light, intermittent toolroom work to automatic production machines of high capacity. There are also machines for angular cutoff. Unlike contour band sawing machines, cutoff machines have no welders; prewelded bands are used (no internal sawing is done). Cutoff band saws can accommodate workpieces as large as 2000 × 2000 mm (80 × 80 in.), and they have cutting rates up to 19 × 10 3 mm 2 /min (30 in. 2 /min) in machine steels using welded-edge high-speed steel band saw blades. Cutting rates as high as 46 × 10 3 mm/min (72 in. 2 /min) are possible when using blades with triple-chip tungsten carbide inserts. Special machines are also available for sawing aluminum alloys at rates of 260 × 10 3 mm 2 /min (400 in. 2 /min). Tilt-frame universal band saws are widely used for angle-cutting operations and for producing compound miters. On these machines, the sawing head is mounted with pivot bearings on a moving carriage. Plate band sawing machines are vertical band saws used for cutting plate stock. These plate saws are gaining acceptance in steel service centers and in the steel-producing industry. Instead of stocking many sizes of bars, the service center can slice a bar from a plate by using this type of saw. The saw blade is thin and produces little waste. These machines have work heights up to 1300 mm (51 in.) and throats up to 1525 mm (60 in.). They are capable of handling lengths up to 6000 mm (236 in.). Fixtures and Attachments Much of the work done on band saws requires a device to hold or guide the workpiece. In contour band sawing, the downward cutting force of the saw band can assist in holding the workpiece to the table and simple, standard attachments are usually adequate. When they are not, special fixtures must be employed. Contour band sawing may also require devices for guiding the workpiece. A work-squaring bar is a simple attachment that serves as a guide in making straight-line cuts. It consists of a movable workstop that is held securely to a backup bar by means of a cam lock. The backup bar acts as the prime locator and is attached to T-slots in the worktable by means of T-nuts and socket-head screws. The movable workstop slides along the calibrated backup bar and can be clamped to it at any point with the cam-locking lever. Contour sawing attachments provide additional capability for holding and rotating the work and for work or table feed. Heavy workpieces are usually handled with table feed and, to minimize friction, are supported on ball transfer strips on the movable table (Fig. 2). The sprocket is mounted on an extension arm that is clamped to the movable table, and the roller chain feeds the workpiece into the saw band. Servo control on the hydraulic feed system maintains a constant feed force at the value selected for the job, regardless of variation in radius of cut, work thickness, work hardness, or other factors. Turning the hand control wheel rotates the sprocket and pulls the chain to rotate the workpiece as needed to follow the contour of the cut. Three positions of a foot switch give forward or reverse feed or stop. Fig. 2 Worktable setup for the contour band sawing of heavy workpieces Light workpieces rest directly on the table and can be manipulated and fed without the use of table feed. Instead, the workpiece is fed into the saw band by a roller chain partly wrapped around the workpiece (or around a work-holding jaw containing the workpiece). In this arrangement, the tablefeed piston is disconnected from the table and exerts the feed force against a movable extension arm that holds the sprocket. Servo control of hydraulic feed pressure can be used, as described above, but it is needed less often than for cutting heavy workpieces. Turning the hand control wheel rotates the workpiece as desired. On fixed-table machines, the feed force can be supplied by weights attached to the chain or by other means, and the work-holding jaw can be rotated manually by handles attached to each end. A servo-feed attachment facilitates the handling of heavy work and improves productivity, resulting in more accurate work handling and the avoidance of underfeed or overfeed. A servo-feed attachment can also result in an improved surface finish, as described in the following example. Example 1: Sawing Aluminum Honeycomb Sections. In the contour band sawing of aluminum hobe blanks (unexpanded honeycomb sections) to obtain a surface finish of 2.8 to 3.8 m (110 to 150 in.), optimum results were obtained with the following tooling and operating conditions: an 8- pitch, regular-form blade; a band speed of 915 m/min (3000 sfm); and a constant, hydraulically controlled feed of 1900 mm 2 /min (3 in. 2 /min) (for a 50 mm, or 2 in., section thickness). These conditions provided a surface finish of 3.3 to 4.0 m (130 to 160 in.). The surfaces obtained by manual feeding were poor. Welders. Most contour band sawing machines are equipped with built-in resistance-type butt welders to make possible the cutting of internal contours. The saw band is cut to length, threaded through a hole drilled in the workpiece for this purpose, and welded into a continuous band. The weld is annealed and ground, and the band is placed on the machine. To obtain optimum cutting performance and maximum life from a saw band, the weld area should be identical in strength and flexibility to the remainder of the band. Welds in carbon steel and welded-edge bands approach this ideal more closely than those in solid high-speed steel or intermediate-alloy tool steel bands, because welds in the latter two materials are somewhat brittle, as a result of the short welding and annealing cycle used. (The solid high-speed steel and intermediate-alloy bands are obsolete.) Vises and Nesting Fixtures. Workpieces must be held securely during cutoff operations. The work is clamped in either a vise or a nesting fixture, depending on the shape, size, and quantity of pieces to be held. Rectangular and square bars can be readily stacked and held firmly in a vise; small and medium-size rounds can also be clamped two abreast and held firmly in a vise. However, holding a larger number of stacked rounds requires the use of a nesting fixture such as that shown in Fig. 3. This type of fixture is widely used for stacking pipe and structural shapes. Stack sawing with the aid of a nesting fixture is most effective when the total area to be sawed is roughly half the capacity of the nesting vise and when the nest is higher than it is wide. Special precautions must be taken in the stack sawing of round pieces to ensure the positive clamping of all pieces because the rotation of a piece during cutting can cause premature band failure. Instead of being stacked as shown in Fig. 3, a number of round, hexagonal, or irregularly shaped bars can be held by special jaws in standard vises. Fig. 3 Nesting fixture used with a standard vise in cutoff band sawing Worktables. The cutoff band saw is usually equipped with at least two work-tables a stack feeding table on which are mounted one or more vises for gripping and indexing the work to be cut, and a discharge table that provides continuous support for the workplace and the stack from which it is cut. These tables are made in various lengths to suit operating requirements, and additional tables can be added to accommodate the longest stack length being handled. Cutting fluid systems are essential for the effective performance of cutoff band saws. They consist of a reservoir and pump, a screening system for chips, draining elements, and a chip drawer or automatic chip remover. The system must be drained and cleaned when changing from one type of cutting fluid to another or when replacing contaminated fluid. Mist or spray systems are sometimes used to apply the cutting fluid. Band Construction and Materials Bands are made of carbon steel or are a bimetallic type. The bimetallic, or composite, types are made with high-speed steel cutting edges that are electron beam welded to a high tensile (AISI 6150) steel back or with tungsten carbide inserts brazed or welded to a high tensile, alloy steel back. These welded-edge composite bands have replaced the carbon and the solid high-speed steel bands. Carbon steel bands are seldom used for the contour band sawing of metals as they have been replaced by the composite welded-edge bands. Fixed-table machines seldom have adequate power, feed mechanisms, and cutting fluid distribution systems for other types of bands. Satisfactory cutting rates and tool life are obtained in sawing carbon and low-alloy steels, tool steels, and the more readily machinable nonferrous alloys. Carbon steel bands come in two types: the flexible-back band and the hard-back band. The flexible-back band is not heat treated across its entire width. Only the teeth are heat treated to increase their hardness and wear resistance. The hard- back band is first heat treated across its entire width to a spring temper. This allows the blade to be tensioned on the band saw to a higher degree for increased beam strength. After spring tempering, the teeth are heat treated to full hardness. A typical nominal composition for carbon steel bands is: Element Composition, % Carbon 1.3 Manganese 0.3 Silicon 0.2 Chromium 0.2 Welded-edge high-speed steel bands are used on heavy-duty machines equipped with systems for circulating cutting fluid. These are usually power-table machines rated at 1.1 kW (1 hp) or more and designed for continuous, high-volume production. The welded-edge bands have replaced the solid high-speed steel bands and are used under the same operating conditions as the solid high-speed steel bands. Welded-edge high-speed steel bands give higher cutting rates and longer tool life than carbon steel bands in cutting the same materials, and they are required for contour sawing the more difficult-to-cut metals, such as stainless steels, heat- resistant alloys, the more highly alloyed tool steels, and some nonferrous alloys. The cutting edge of these bands are usually made of M2, Matrix 2 or M42 high-speed steel. (See Table 2 for material composition.) Welded-edge bands coated with titanium nitride are also available for difficult applications and increased tool life. Table 2 Band saw blade composition Composition, % Hardness, HRC Product C Si Mn Cr V W M Co Heat resistance, °C (°F) Teeth Body M-2 high-speed welded-edge band saw 0.79- 0.86 0.25 0.35 4.25 1.95 6.50 5.00 . . . 540 (1000) 64-66 40-47 Matrix band saw 0.70- 0.78 0.30 0.25 4.25 1.00 1.00 5.00 8.00 590 (1100) 65-67 40-47 Cobalt M-42 band saw 1.05- 1.10 0.25 0.25 3.75 1.15 1.50 9.50 8.00 700 (1300) 67-69 40-47 Carbide Inserts. Bands with tungsten carbide cutting edges brazed or welded to an alloy steel back are used for cutting the most difficult-to-machine alloys, such as nickel-base and cobalt-base heat-resistant alloys, and for sawing sections thicker than about 150 mm (6 in.) of common metals. Compared to high-speed steel, these blades have relatively low shock resistance, but they provide maximum hot hardness and wear resistance. Hardening of Bands. Heat-treating procedures vary with band material and manufacturer. Hardness of the teeth for carbon steel bands is usually 63 to 65 HRC after tempering. To improve service life and cutting performance, special procedures are employed to impart increased hardness and strength to the body of the band by increasing back hardness from 25 to 32 HRC to 40 to 47 HRC. Most manufacturers flame harden or induction harden the cutting edges to about 63 or 65 HRC. The components of welded-edge high-speed steel bands are selected so that optimum properties for the teeth and the back of the band are developed in a single-temperature heat treatment. The composite bands combine the welding characteristics and fatigue properties of carbon steel with the heat resistance and wear resistance of high-speed steel. Tooth Form As shown in Fig. 4, steel bands are available in three tooth forms: regular, skip, and hook; bands with carbide inserts are also available in a special form. Individual manufacturers of saw bands have referred to the tooth shapes by various names; the terminology followed in this article is based on "Simplified Practice Recommendation R214-55" (U.S. Department of Commerce). Fig. 4 Standard tooth forms for steel and carbidetip bond saw blades The regular form is the only form available for saws that are finer than 6-pitch in straight teeth or uniform number of teeth per 25 mm (1 in.). For 6-pitch and coarser, the hook form provides the best tool life and the fastest cutting rate. For optimum surface finish, either a regular or a skip tooth form is usually recommended. The regular tooth form is most frequently used in contour band sawing. It has a deep gullet with a smooth radius at the bottom. The rake angle is normally 0°, although positive rake angles applied to regular tooth forms allow faster cutting and are now available from most manufacturers. The back clearance angle is about 30° (see Fig. 5 for an explanation of the nomenclature applied to blade angles). This tooth form produces fine-finish cuts accurately and has ample chip capacity for most sawing operations. The largest selection of widths is available in this form. Fig. 5 Standard nomenclature for saw blade teeth. The skip tooth form is similar to the regular tooth form except that the teeth are more widely spaced to provide greater chip clearance. The skip tooth form has a special gullet design, but rake angle and back clearance angle are the same as in the regular tooth form. Because of its shallow gullet, the skip tooth form may have a coarser pitch on a narrow band. This tooth form is recommended for making deep cuts in soft metals. The hook tooth form has a positive rake angle that permits faster cutting rates, reduced feeding pressures, and longer tool life. The back clearance angle is slightly less than that of the regular and skip tooth forms, and the wide gullet is of a special design. Blade Design Pitch, width and thickness of the blade, and type of set and set dimension are important factors in the selection of a blade for a particular application. The pitch of a saw blade is the number of teeth per 25 mm (1 in.) of blade. Each of the tooth forms previously discussed is available in various pitches. The pitch of a blade is primarily selected on the basis of the thickness and shape of the cross section to be cut; the type of material to be cut is of minor importance. Therefore, a given cross-sectional thickness of aluminum, low-carbon steel, or tool steel would be cut with blades having identical pitch, although speed and feed would vary. At least two teeth must remain in contact with the workpiece at all times; it is preferable to have more teeth in constant contact, thus reducing proportionately the load on each tooth and increasing tool life. Therefore, thin sections are usually sawed with a blade of 10-pitch or finer, while heavier sections employ a coarser pitch. A pitch as coarse as 3 or 4 is used to cut thick sections, and bands with a pitch less than 1 tooth per 25 mm (1 in.) have been developed for sawing very thick sections. Aside from the basic relationship between tooth pitch and the thickness of the workpiece to be cut, a tooth that is too small for a given application will cut at a slow rate and will bind and load up. If a tooth is too large for the application, tooth breakage and stripping are likely. The noise from band sawing can be reduced by using blades with different pitch combinations. These blades have a variable pitch pattern, where the spacing between the teeth varies and repeats itself about every 25 to 50 mm (1 to 2 in.). This variable spacing of the teeth causes interference in the sound patterns thus reducing the amplitude of the resultant noise. Variable tooth spacing also reduces the amplitude of vibrations, which is particularly important when sawing thin workpieces. Blade Width. Beam strength increases in proportion to the cube of the blade width, thus permitting the use of higher feed force. In addition, the accuracy of cutting along a straight line is greater for wider blades. Instead of increasing blade width when greater beam strength is needed for difficult straight cuts, the band is sometimes supported by a carbide-faced backup plate of the same thickness. The thickness (or gage) of a saw blade is usually not open to choice; it has been standardized. Therefore, blades that are 13 mm ( in.) in width or less are generally 0.64 mm (0.025 in.) thick, 16 and 19 mm ( and in.) widths are generally 0.81 mm (0.032 in.) thick, and a 25 mm (1 in.) width is 0.89 mm (0.035 in.) thick. Blades that are 32 mm (1 in.) wide are generally 1.1 mm (0.042 in.) thick, a 38 mm (1 in.) width is generally 1.3 mm (0.050 in.) thick, and widths from 50 to 120 mm (2 to 4 in.) are 1.6 mm (0.063 in.) thick. Beam strength increases linearly with thickness. In general, a blade of standard gage is adequate for all applications except those involving large workpieces and requiring extreme accuracy. For these applications, a heavier gage is recommended because it will offer increased resistance to side displacement. Similarly, in cutting the more difficult-to-machine alloys, a thicker blade will cut more efficiently up to the full capacity of the machine. Set. The teeth of a saw band are intentionally offset to provide clearance for the back of the band and to permit the cutting of contours. The set dimension is the distance from the extreme corner of one tooth to the extreme corner of the tooth set to the opposite direction. The maneuverability of the band increases as band width decreases (Table 3) and as the set dimension increases. Table 3 Recommended band width for the contour sawing of various radii Radius to be cut Band width mm in. mm in. <1.6 1.6 1.6 2.4 3.2 3.2 8 4.8 16 6.4 36.5 1 9.5 65 2 13 95 3 16 140 5 19 180 7 25 1 300 12 32 1 530 21 38 1 710 28 50 2 Both the raker and wavy set patterns are used for sawing metals (Fig. 6). The raker pattern is developed by a series of three consecutive teeth: one set to the left, one on center and one to the right. This pattern is repeated for each successive group of three teeth. (Raker set is also available in 5/7 pitch combination patterns.) In contrast, the wavy pattern consists of series of teeth that are gradually offset, first to the right and then to the left, to form a wavelike pattern. Fig. 6 Set patterns for saw blades Raker set blades are recommended for all sawing applications except those involving workpieces with marked changes in cross section, such as tubing, pipe, and structural shapes, or in thin cross sections. The wavy set performs better than the raker set in thin cross sections because they cut into the work more gradually and uniformly, thus minimizing shock loading of the cutting teeth. Special Saw Blades. In addition to the types of blades already described, three special types spiral tooth, diamond edge, and aluminum oxide edge are available. The spiral tooth blade is capable of cutting accurate contours to a minimum radius of 0.25 mm (0.010 in.). Because it has an effective cutting edge of 360°, it is well adapted to cutting intricate patterns in light-gage metal. Diamond-edge and aluminum-oxide-edge blades can be used to cut metals that are extremely tough, such as nickel-base and cobalt-base heat-resistant alloys and steel that has been heat treated to high hardness. Both types of blade generate a great deal of heat, and the use of a cutting fluid is mandatory. Band Selection The most widely used welded-edge high-speed steel bands are available in at least three metallurgical grades: M2, Matrix 2, and M42 (see Table 2 for material composition). For the production sawing of a very thin walled steel tubing (<1.5 mm, or 0.060 in.) or a very small bar size, M2 with a tooth tip hardness of 64 HRC is recommended. For sawing carbon and alloy steels, a cutting edge of Matrix 2 with a tooth tip hardness of 67 HRC or variable pitch blades with Matrix 2 edges are recommended. For sawing high-temperature alloys, heat-treated steels, stainless steels (such as type 304, type 316, type 347, and 17-4PH), and superalloys such as A-286, an M42 tooth tip hardness of 69 HRC is advised. When sawing diameters of 100 mm (4 in.) or greater, the M42 blades are most suitable. In addition, the M42 blades should have a positive rake, rather than the standard 90° rake design, for easier and greater penetration. Finally, when sawing superalloys such as Inconel 718, Waspaloy, Astroloy, and 6/4 alloy titanium in large sizes, improved efficiency may be achieved by using carbide-tip band blades. Special welded-edge blades are also available for these applications. They utilize changing width patterns to force the teeth to cut below any work-hardened layers. Welded-edge blades are generally more economical than carbide-tipped blades for these applications. Band Width. To maintain accuracy and a high cutting rate, the widest band capable of cutting the desired radius should be used during contour band sawing (Table 3). Wider bands are also used in cutoff operations because only straight-line cuts are made. Wider bands provide greater beam strength and permit higher loading. Bands 25 to 125 mm (1 to 5 in.) wide are preferred in cutoff operations. Noise Reduction. When the pitch of the blade is varied (or modulated), a smoother, quieter operation results. At recommended speeds, the noise from a pitch-modulated blade seldom exceeds 80 dB. Machining Variables Speed, feed, and thickness of work are variables in cutoff and contour band sawing operations. Metal composition, hardness, structural homogeneity, and work-hardening potential are also important variables. Cutoff Operations. Nominal speed, cutting rate, and band life for the cutoff band sawing of various metals are given in Tables 4 and 5. Tables 4 and 5 are based on the cutting of scale-free rounds, 75 to 125 mm (3 to 5 in.) in diameter, with 25 mm (1 in.) wide high-speed steel bands, and are applicable to solid bar stock up to 450 mm (18 in.) thick. Substantial amounts of scale on the work will necessitate the use of lower band speed and cutting rate and will shorten band life, particularly in cutting thin material. Table 4 Nominal speed, cutting rate, and band life for the cutoff band sawing of steel bars Band speed (a) Cutting rates (a) Band life in terms of total area cut (b) Steel being cut Hardness, HB m/min sfm mm 2 × 10 3 /min in. 2 /min mm 2 × 10 6 in. 2 × 10 3 Carbon and low-alloy steels 1008-1013 150-175 100-84 325-275 9.0-6.4 14-10 4.3 6.7 1015-1035 160-175 106-90 350-300 9.7-7.1 15-11 4.8 7.5 1036-1064 160-180 68-58 225-190 5.8-4.5 9-7 2.7 4.2 1065-1095 180-205 52-44 170-145 5.2-3.9 8-6 1.9 3.0 1108-1132 125-175 106-84 350-275 9.7-7.7 15-12 5.2 8.0 1137-1151 155-180 80-68 260-225 6.4-5.2 10-8 3.5 5.4 1212-1213 150-175 106-90 350-300 9.7-7.7 15-12 5.5 8.5 1330-1345 200-220 65-58 210-190 5.2-3.9 8-6 2.3 3.5 4023-4047 170-220 80-70 260-230 5.2-3.9 8-6 2.4 3.7 4130-4140 190-215 75-67 250-220 5.8-4.5 9-7 2.1 3.3 4320-4340 200-250 70-55 230-180 4.5-3.2 7-5 1.9 3.0 4815-4820 220-240 58-53 190-175 3.9-2.9 6-4.5 1.6 2.5 5046 170-190 75-67 250-220 5.8-4.5 9-7 2.1 3.3 5140-5160 200-220 70-60 230-200 4.2-3.2 6.5-5 1.6 2.5 50100-52100 210-230 50-37 170-120 3.9-2.6 6-4 1.6 2.5 6118-6150 180-220 68-45 225-150 4.8-2.6 7.5-4 1.7 2.6 8615-8645 160-220 70-53 230-175 4.5-3.2 7-5 2.5 3.8 8720-8740 180-215 68-53 225-175 4.5-3.2 7-5 2.05 3.2 9310 210-240 53-45 175-150 2.6-1.9 4-3 1.3 2.0 Tool steels W1 155-195 67-55 220-180 3.9-3.2 6-5 1.9 3.0 S2, S5 175-230 45-33 150-110 2.6-1.9 4-3 1.0 1.5 O1, O2 190-205 65-55 210-180 3.9-2.6 6-4 1.6 2.5 A2 215-240 60-52 200-170 2.6-1.9 4-3 1.5 2.3 D2, D3 215-240 37-27 120-90 1.9-1.3 3-2 1.0 1.5 D7 230-255 27-18 90-60 1.3-0.6 2-1 0.55 0.85 H12, H13, H21 205-230 58-49 190-160 3.2-2.6 5-4 1.3 2.0 T1, T2 215-250 40-30 130-100 2.3-1.3 3.5-2 1.1 1.7 T6, T8 220-295 30-21 100-70 1.6-0.6 2.5-1 0.7 1.2 T15 230-255 23-15 75-50 1.3-0.6 2-1 0.6 1.0 M1 215-230 45-37 150-120 3.2-1.9 5-3 1.1 1.7 M2, M3 215-240 33-24 110-80 2.6-1.3 4-2 1.0 1.5 M4, M10, M15 215-230 27-18 90-60 1.6-0.6 2.5-1 0.7 1.2 L6 190-230 55-49 180-160 3.9-2.6 6-4 1.6 2.5 Stainless steels 201, 202, 302, 304 130-190 37-24 120-80 2.6-1.3 4-2 1.9 3.0 303, 303F 150-200 40-27 130-90 3.2-1.3 5-2 2.1 3.3 308, 309, 310, 330 160-220 24-18 80-60 1.3-0.6 2-1 0.85 1.3 314, 316, 317 160-220 23-15 75-50 1.3-0.6 2-1 0.75 1.2 321, 347 165-200 37-27 120-90 2.6-1.3 4-2 1.5 2.4 410, 420, 420F 140-185 43-30 140-100 2.6-1.3 4-2 1.0 1.5 416, 430F 155-195 55-43 180-140 4.5-3.2 7-5 1.6 2.5 430, 446 170-215 27-18 90-60 2.6-1.9 4-3 1.1 1.7 440A, B, C 160-190 33-21 110-70 2.6-1.3 4-2 1.0 1.5 440F, 443 175-215 40-30 130-100 2.6-1.3 4-2 0.8 1.3 17-7 PH, 17 4 PH 150-360 27-15 90-50 2.6-1.3 4-2 1.1 1.7 (a) Based on the use of a 25 mm (1 in.) wide high- speed steel band, regular tooth form (except hook tooth form for metal thicker than about 250 mm, or 10 in.), raker set, to cut scale- free, solid bar stock up to 460 mm (18 in.) thick; based on the use of a cutting fluid, except for D2, D3, and D7 tool steels, which are cut dry. (b) For 3 m (10 ft) band; proportionate life for other band lengths Table 5 Nominal speed, cutting rate, and band life for the cutoff band sawing of nonferrous alloys Band speed (a) Cutting rate (a) Band life in terms of total area cut (b) Work metal Hardness, HB m/min sfm mm 2 × 10 3 /min in. 2 /min mm 2 × 10 6 in. 2 × 10 3 Copper alloys 100-120 84-60 275-200 5.2-3.9 8-6 2.5 3.8 220-250 68-53 225-175 3.9-2.6 6-4 1.7 2.7 170, beryllium copper 310-340 43-27 140-90 1.9-1.3 3-2 1.1 1.7 60-100 90-75 300-250 6.4-5.2 10-8 3.7 5.8 510, phosphor bronze 5% A 180-210 53-38 175-125 3.2-1.9 5-3 1.6 2.5 70-90 106-90 350-300 9.0-6.4 14-10 4.3 6.7 614, aluminum bronze D 190-220 53-38 175-125 3.2-1.9 5-3 1.6 2.5 70-100 100-384 325-275 9.7-7.7 15-12 4.8 7.5 656, high-silicon bronze 180-210 53-38 175-125 3.9-1.9 6-3 1.6 2.5 95-120 100-584 325-275 9.7-7.7 15-12 4.8 7.5 675, manganese bronze A 180-190 60-45 200-150 3.9-2.6 6-4 1.7 2.7 Nickel alloys Inconel 150-200 30-18 100-60 1.9-1.3 3-2 0.4 0.65 Inconel X-750 200-300 24-18 80-60 1.0-0.3 1.5-0.5 0.25 0.4 Monel 400 125-200 30-18 100-60 1.9-0.6 3-1 0.55 0.85 Monel R-405 145-180 45-23 150-75 2.6-1.3 4-2 0.6 1.0 Monel K-500 160-210 24-18 80-60 1.3-0.3 2-0.5 0.3 0.5 Monel 501 160-210 30-18 100-60 1.9-0.6 3-1 0.5 0.85 Hastelloy A 210-260 37-23 120-75 1.9-1.0 3-1.5 0.6 1.0 Hastelloy B 230-270 30-23 100-75 1.6-0.6 2.5-1 0.55 0.85 Hastelloy C 185-250 27-18 90-60 1.0-0.45 1.5-0.7 0.38 0.6 Titanium alloys Ti; Ti-1.5 Fe-2.5 Cr 270-350 27-18 90-60 0.6-0.2 1-0.3 0.25 0.4 Ti-4 Al-4 Mn; Ti-6 Al-4 V 290-360 33-21 110-70 1.3-3.9 2-6 1.5 2.4 Ti-2 Fe-2 Cr-2 Mo 300-330 27-18 90-60 1.0-0.3 1.5-0.5 0.48 0.75 [...]... low-alloy steels Data are based on the use of a suitable cutting fluid Steel being cut 100 8-1 013 101 5-1 035 103 6-1 064 106 5-1 095 110 8-1 132 113 7-1 151 121 2-1 213 133 0-1 345 402 3-4 047 413 0-4 140 432 0-4 340 481 5-4 820 5046 514 0- 5160 5010 0-5 2100 611 8-6 150 861 5-8 645 872 0-8 740 9310 Hardness, HB 15 0-1 75 160 -1 75 160 -1 80 18 0-2 05 12 5-1 75 15 5-1 80 15 0-1 75 20 0-2 20 17 0-2 20 19 0-2 15 20 0-2 50 22 0-2 40 17 0-1 90 20 0-2 20 21 0-2 30... 330(d) 314( d), 316( d), 317(d) 321, 347 410, 420, 420F 416, 430F 430, 446 440 A(d), B(d), C(d) 440F, 443 1 7-7 PH(d), 1 7-4 PH(d) 13 0-1 90 15 0-2 00 160 -2 20 160 -2 20 165 -2 00 14 0-1 85 15 5-1 95 17 0-2 15 160 -1 90 17 5-2 15 15 0-3 60 Speed, m/min (sfm), for stock thickness of: 6. 4-1 3 mm 2 5-7 5 mm 15 0-3 00 mm ( 1-3 in.)(b) ( 6-1 2 in.)(c) ( - in.)(a) 45 (150) 30 (100) 21 (70) 49 (160 ) 40 (130) 30 (100) 33 (110) 24 (80) 15 (50) 29... bands Typical steel(a) Speed m/min Carbon and low-alloy steels (except free-cutting steels) 85 1020, 1045, 4140 , 7140 , and 8620 8 5-1 25 12 5-1 75 82 17 5-2 25 70 22 5-2 75 49 27 5-3 25 40 32 5-3 75 30 Free-cutting steels 10 0-1 50 87 1112 and 1117 15 0-2 00 90 98 1137, 12L14, 4140 +S, and 41L40 10 0-1 50 15 0-2 00 85 20 0-2 50 69 27 5-3 25 47 32 5-3 75 30 Hardness, HB sfm 280 270 230 160 130 100 285 295 320 280 225 155 100 Source:... contour band sawing of cast iron (12 5-2 50 HB) with high-speed steel and carbon steel saw bands Data are based on dry sawing Work (ASTM grade) metal High-speed steel bands(d) Gray iron Class 30 Class 35; Class 40 Nodular iron 6 0-4 5-1 0; 6 5-4 5-1 2 8 0-6 0-0 3; 8 0-5 5-0 6 10 0-7 0-0 3 Malleable iron 32150; 35018 53004; 60003 Carbon steel bands(e) Nodular iron 6 0-4 5-1 0; 6 5-4 5-1 2 Malleable iron 32510; 35018 Speed,... D7(g) H12, H13, H21 T6(g), T8(g) M4(g), M10(g), M15(g) L6 (a) (b) (c) (d) (e) (f) (g) Hardness, HB 15 5-1 95 17 5-2 30 18 5-2 05 21 5-2 40 21 5-2 40 23 0-2 55 20 5-2 30 22 0-2 95 21 5-2 40 19 0-2 30 Speed, m/min (sfm), for stock thickness of: Carbon steel bands 6. 4-1 3 mm 2 5-7 5 mm 15 0-3 00 mm ( 1-3 in.)(c) ( 6-1 2 in.)(d) (b) ( - in.) 45 (150) 30 (100) 15 (50) 24 (80) 15 (50) 15 (50) 45 (150) 30 (100) 15 (50) 50 (170) 30 (100)... stock thickness of: 6. 4-1 3 mm 2 5-7 5 mm 15 0-3 00 mm ( 1-3 in.)(b) ( 6-1 2 in.)(c) ( - in.)(a) 76 (250) 60 (200) 56 (185) 44 (145 ) 33 (110) 50 (165 ) 120 (400) 73 (240) 60 (200) 90 (300) 55 (180) 44 (145 ) 60 (200) 33 (110) 49 (160 ) 106 (350) 70 (230) 75 (250) 49 (160 ) 49 (160 ) 49 (160 ) 76 (250) 60 (200) NR 64 (210) NR NR Source: Data are adapted from tables in "Fundamentals of Band Machining, " Wilkie Brothers... 10-pitch for high-speed steel bands, 1 4- pitch for carbon steel bands; minimum feed force Regular tooth form; 6-pitch for high-speed steel bands, 8-pitch for carbon steel; average feed force Hook tooth form for class 30 gray iron, 6 0-4 5-1 0 and 8 0-6 0-0 3 nodular, and 32510 malleable, and carbide tooth form for the other cast irons; 2. 5- to 3-pitch; maximum feed force Data are also suitable for welded-edge... fluid Work metal Hardness, HB A-286 Discaloy Hastelloy A Hastelloy B Hastelloy C Inconel Inconel 700 Inconel X-750 Waspaloy U-500 René 41 Refractaloy 26 21 0-2 60 23 0-2 70 18 5-2 50 15 0-2 00 Speed, m/min (sfm), for stock thickness of: 6. 4-1 3 mm 2 5-7 5 mm 15 0-3 00 mm ( 1-3 in.)(b) ( 6-1 2 in.)(c) (a) ( - in.) 23 (75) 15 (50) 15 (50) 24 (80) 20 (65) 20 (65) 24 (80) 17 (55) 15 (50) 27 (90) 18 (60) 17 (55) 24... 22 0-2 40 17 0-1 90 20 0-2 20 21 0-2 30 18 0-2 20 160 -2 20 18 0-2 15 21 0-2 40 Speed, m/min (sfm), for stock thickness of: Carbon steel bands 6. 4-1 3 mm 2 5-7 5 mm 15 0-3 00 mm ( 1-3 in.)(c) ( 6-1 2 in.)(d) ( - in.)(b) 60 (200) 45 (150) 38 (125) 68 (225) 53 (175) 38 (125) 45 (150) 30 (100) 23 (75) 45 (150) 30 (100) 20 (65) 80 (260) 65 (210) 41 (135) 68 (225) 53 (175) 33 (110) 84 (275) 68 (225) 44 (145 ) 45 (150) 30 (100) 21 (70)... R R R 14 14 14 14 14 14 14 14 14 14 2590 460 1520 460 300 430 1520 430 850 430 8500 1500 5000 1500 1000 140 0 5000 140 0 2800 140 0 R R R R R R R R R R 6 6 6 6 6 6 6 6 6 6 1980 240 1070 240 180 275 1220 275 730 275 6500 800 3500 800 600 900 4000 900 2400 900 H H H H H H H H H H 3 3 3 3 3 3 3 3 3 3 1525 90 760 90 60 90 910 90 610 90 5000 300 2500 300 200 300 3000 300 2000 300 R R R 10 10 14 90 84 120 300(e) . 15 0-2 00 4 0-2 7 13 0-9 0 3. 2-1 .3 5-2 2.1 3.3 308, 309, 310, 330 160 -2 20 2 4-1 8 8 0-6 0 1. 3-0 .6 2-1 0.85 1.3 314, 316, 317 160 -2 20 2 3-1 5 7 5-5 0 1. 3-0 .6 2-1 0.75 1.2 321, 347 165 -2 00 3 7-2 7 12 0-9 0 2. 6-1 .3. R-405 14 5-1 80 4 5-2 3 15 0-7 5 2. 6-1 .3 4-2 0.6 1.0 Monel K-500 160 -2 10 2 4-1 8 8 0-6 0 1. 3-0 .3 2-0 .5 0.3 0.5 Monel 501 160 -2 10 3 0-1 8 10 0-6 0 1. 9-0 .6 3-1 0.5 0.85 Hastelloy A 21 0-2 60 3 7-2 3 12 0-7 5. low-alloy steels 100 8-1 013 15 0-1 75 10 0-8 4 32 5-2 75 9. 0-6 .4 1 4-1 0 4.3 6.7 101 5-1 035 160 -1 75 10 6-9 0 35 0-3 00 9. 7-7 .1 1 5-1 1 4.8 7.5 103 6-1 064 160 -1 80 6 8-5 8 22 5-1 90 5. 8-4 .5 9-7