Info

L-r** inwpe'Ulnfl hirniCM in which Cm tflp J hHt MWtinm W t*lnn JUnj TTn 11hM inHncnu aqu lpm*nr oomrilUngwutins nwH. wrm llnim nd flHnM a< tlx Np tntt HUtillfl. WhK ir meff l.nin i pt du i rn Iddlfcwiil to'iltM alldyi HI* Cfl in( wrchtlM * bntrFtv CMiin . Figure 1.14 Mill trains for producing hot- and cold-rolled strip capabilities include rewinding to coil or cutting to length, side Roll trains for producing hot and cold rolled strip are shown By the use of a cluster mill such as the...

1323 Nodular graphite iron

Nodular or spheroidal graphite (SG) cast irons are available in grades corresponding to those of grey cast iron, but are produced by inoculation of the melt with nickel, magnesium and caesium compounds which change the form of the graphite to near spheroidal nodules (see Figure 1.38). This produces material which has strength, ductility and thermal shock resistance more typical of steel but castability, damping capacity and machinability more typical of cast iron. The recommended design,...

360

The output voltage of a two-coil, two-pole d.c. can be increased the number of turns on each coil can be increased and another pair of poles can be introduced. A typical d.c. machine would therefore normally incorporate four poles, wired in such a way that each consecutive pole has the opposite magnetic polarity to each of its neighbouring poles. If the e.m.f.s generated in the armature coils are to assist each other then, while one side of the coil is moving under a north pole, the other side...

24 General properties of plastics

Since plastics may be regarded as those polymers that are not rubbers, fibres, adhesives or surface coatings, the range of properties possible is very wide. Some materials such as low-density polyethylene and plasticised PVC are flexible the polyurethane foams are flexible and, in some cases, rubbery glass-reinforced polyester laminates are hard and rigid whilst the nylons are less rigid but tough. Some plastics dissolve in water, others have excellent resistance to a wide range of chemicals....

817 Machining with coated abrasives

Abrasive belts are widely used to machine both metallic and non-metallic materials. A wide variety of machines has been developed to utilise the full potential of abrasive belts these range from simple off-hand grinders to fully automated special-purpose machines. An abrasive belt consists of four constituent parts backing, bond, grit and joints. Each constituent has a significant effect on cutting performance. Backing Both cloth and paper backings are available in varying stiffnesses. Y weight...

R6

Contour generation using wheel with two different corner radii 1 Plunge grind 3 mm radius R3 R5j 2 6 mm radius generation J j V 3 12 mm radius blending with 45 angle, generated 4 10 angle, 10 mm blend radius. 30 angle generated M.91 examples of wheeiforming combinations M.91 examples of wheeiforming combinations Figure 8.21 Circular and linear interpolation for contour generation. (Courtesy of Jones and Shipman pic) proportion of its time cutting metal and gives very substantial reductions in...

06

Figure 5.37 Influence of machine rate per minute on cost (a) ki 0.15 (b) it, 0.40 and factory overhead it is obvious that, when using expensive equipment, round-the-clock operation and high utilisation are very important. (3) The value of A has a dramatic effect on the shape of the cost curve and on the minimum cost values, as shown in Figure 5.38. Low values of A give a very cost-sensitive curve, with low optimal cutting speeds. Large values of A, associated with the newer high performance...

J wW

Figure 4.69 The effect of height reduction on the stress pattern induced during the upsetting of circular sections Figure 4.70 (a) Direction of forces and pressures in shaped upsetting dies, (b) Stress patterns and angles of engagement in shaped dies Figure 4.70 (a) Direction of forces and pressures in shaped upsetting dies, (b) Stress patterns and angles of engagement in shaped dies turning the work piece to different positions between successive blows. The deforming forces are applied either...

T

Provided the open-circuit gain of the amplifier is very high, the overall gain with this negative-feedback system is given by the ratio of the two external resistors and is independent of the open-circuit gain. Figure 10.47 depicts a unity gain amplifier in which no external resistors are wired into the circuit. The unity gain amplifier is also known as a 'voltage follower', or as a 'buffer amplifier'. This type of amplifier circuit is often used in instrumentation systems where the internal...

72 Manual assembly of throughhole components

Figure 7.1 shows the stages involved in the manual assembly of PCBs with through-hole components. The types of assembly method currently used in industry depend on the quantity and the variety of boards required. There are three types of manual production which are commonly used. In the case of high throughput, automatic machines are available. Manual assembly of through-hole components 7 3 7.2.1 Low throughput In this type of assembly an operator completes the entire board, including...

25

Figure 8.6 Superabrasive marking system. (Courtesy Carborundum Abrasives GB Ltd) machine after a final check of wheel size, bore fitting, flanges and maximum operating speed. The wheel should fit easily onto the spindle and is clamped into position using the correct flanges and washers, as appropriate. Where a nut is used to clamp the wheel in position this should tighten up in the opposite direction of rotation of the wheel. Although the wheel should be held securely, over-tightening must be...

411 Superplastic and mashy state forming

The definition of the term 'superplasticity' is related to the fact that 'normal' alloys rarely show a greater degree of elongation than, at most, 60 when cold worked and only very occasionally exceed 100 when hot worked. In a few cases (Table 4.15) metallic alloys elongate at elevated temperatures to as much as 10 times their original length these are called 'superplastic' materials. A number of alloys behave superplastically at temperatures ranging from ambient to 500 C but, because they are...

1025 750 9100

Extrusion ratios apply to sections, not tubes. Profiled or bell-mouthed dies are essential for the Ugine-Sejournet process. Hollows using mandrels. Simple shapes Heating of billets is of great importance, not only from the point of view of the time involved, but also in terms of the economics of the possible descaling operation. The general trend appears to be towards the low frequency inert gas atmosphere heating of billets. Theoretically, the economic use of a low frequency induction furnace...

57 Toollife assessment

It is fortunate that, with few exceptions, tool wear occurs in a predictable manner. Although it takes different forms, each form of tool wear is associated with a known cause which happens within particular ranges of feed and cutting speed. The production engineer's initial task in optimising the metal cutting process is to decide which form of wear is to be accepted, and then to work within the constraints which such wear imposes. Before pursuing this line of thought further, it Figure 5.29...

410 Highenergyrate operations

The last three decades have seen the development of industrial forming techniques based on the utilisation of high-energy-rate dissipation. The dynamic aspects and mechanisms of these operations make it possible to manufacture, usually fairly economically, either large components, such as radar Figure 4.136 Conventional stretch forming Figure 4.136 Conventional stretch forming the supporting die or anvil. Instability can set in and lead to failure through localised necking. Dynamic or explosive...

Redundant

Angular or linear distortion of structure Angular or linear distortion of structure Coincidence of incipient cracks with layers of sulphur and phosphorus Figure 4.17 Components of total deformation But, A nR2, and dA 2nRdR, and S ttR and so dS TrdR. On substituting these values into equation (4.2a), and accounting for the constancy of volume (equation (4.1a)), the strain increments become de, dey - de2 - - (4.2b) This approach is adopted in all metal-forming processes, but naturally the...

100 50

Figure 1.49 Effect of temperature on (a) 0.2 proof stress, and (b) ultimate tensile strength of various magnesium cast alloys. (Reproduced by permission of Mr. W. Unsworth, Magnesium Elektron Ltd) alloy (ZT) is available but its application is restricted compared with that of castings. 1.4.4.6 Corrosion of magnesium alloys The improved corrosion resistant alloys of magnesium have been referred to in Section 1.4.4.3. The high purity casting alloys have performed at least as well as high...

220600

The wheel grade indicates the strength of bond holding the wheel together. If the bond is weak the wheel is said to be 'soft'. When grits become blunt in a soft wheel they are readily torn out to expose new sharp grits a mechanism known as 'self-sharpening'. Since soft wheels are less likely to dull, they tend to give a cooler cut. Hard wheels are strongly bonded together and are less likely to exhibit self-sharpening their use is favoured in finishing operations. Wheel grade is specified by a...

2014t4

Is normally painted in severe industrial environments and for marine service. May be anodised as above Painting needed in marine and industrial atmospheres, but coatings need only infrequent renewals. Sprayed aluminium coatings, or cladding, give excellent protection. Seldom anodised * Reproduced by permission of the heirs of Dr E. A. West. t Aluminium retains its initial appearance if it is washed periodically (3- to 12-month intervals), depending on the severity of the...

5

Figure 4.120 Patterns of flow and fault formation in wire drawing, (a) Dead-metal zone, (b) Chip with or without a built-in edge, (c) Central burst and redundancy effects, and can be estimated from the following empirical expressions (see the Bibliography) where a is area reduction, x is the coefficient of friction, m is the friction factor, and R, and Rf are the initial and final radii of the wire, respectively. The magnitude of the drawing stress depends not only on the pass geometry, general...

Htv

Figure 5.41 Typical minimum cost and maximum power constraints no comparable analysis exists, it would seem reasonable that, if the optimum life for a single-point cutter is 15 min, that for an eight-tooth cutter would be of the order of 2-3 h. With multipoint cutters the problems associated with catastrophic failure are less acute, since the failure of one cutting edge will not pose a dangerous threat. Usually, cutting is allowed to proceed until the generated surface is deemed to be...

0008

The toughness of these materials will be correspondingly affected (Figure 4.4). Consequently, if dynamic working conditions are likely to prevail in the selected process, a classification based on the strain rate may offer a more realistic means of assessment, particularly in the case of cold-forming operations. Since some modern processes do not require bulk solids as starting materials, but utilise particular matter and semi-solid substances, a classification based on the initial physical...

111 Elastic properties

Elastic or Young's modulus, E (units GPa) The stress required to produce unit strain in the same direction, i, in the absence of restraint in the orthogonal directions where a is the stress and e the strain which it produces. A standard testing method is described in ASTM E231. Shear modulus, G (units GPa) The shear stress required to produce unit angular rotation of a line perpendicular to the plane of shear where T is the shear stress and 4> is the angular rotation (in radians). Bulk...

84 Mounting the grinding wheel

The Abrasive Wheel Regulations 1970 require that 'no person shall mount an abrasive wheel unless he has been trained to do so or is competent to do so'. Employers are also required to keep a register of persons appointed to mount grinding wheels and the class of wheels which they can mount. Having selected the correct type and size of grinding wheel for the particular grinding machine or operation, the wheel should be examined carefully to ensure that it is free from defects. Visual inspection...

90115 340432 6273 5862 7080

* Reproduced by courtesy of Magnesium Elektron Ltd. t The tensile properties quoted are the specification minima for the first specification listed for that alloy and condition. Hie ranges given are the specified minima bracketed values are for information only. The values quoted are for separately cast test bars and may not be realised in certain portions of castings. MoD, Ministry of Defence. dies are not attacked by molten magnesium as they are by molten aluminium. Magnesium is readily...

R1 R 2 R

If the resistances used in the circuit are all of equal value, then the output voltage will be equivalent to the summation of all the input voltages and with a reversed sign. Subtraction of any of the voltages can be performed by reversing its polarity, i.e. by first of all passing the voltage through a unity gain inverting amplifier, before it is passed on to the summing amplifier. The integrating amplifier uses a capacitor, as opposed to a resistor, in the feedback loop (see Figure 10.50)....

1

Where subscripts 1 and 2 refer to the entry and exit, respectively, k Y 2 is the yield stress in pure shear, h is the strip thickness, p is the coefficient of friction, and where < > is the angle subtending the arc of engagement considered. Both of the equations above are obtained by using the equilibrium of forces analytical method, and by considering the geometry of the system. The roll force, P The roll force per unit length is given by r*i

31 Economics of casting and moulding

Casting may be defined as 'metal shaping obtained by the solidification of molten alloy in the mould cavity of a required shape'. Of course, there are also other methods of shaping metal, i.e. forging, stamping, rolling, machining or welding. In practice, wrought iron is cast as ingots, and then plastically worked into the required shape. This means that all primary alloy metals are cast first. The process of casting has certain advantages over the other processes of shaping (1) it can be...

112 Tensile testing parameters

When considering the properties obtained from the tensile test it should be realised that the results are always reported as though the load was applied to the initial cross-section Aa of the test piece. Any reduction of this cross-section is ignored. The test subjects a sample of material of circular or rectangular cross-section, of a specific gauge length and equipped with end pieces of larger section which taper smoothly to the gauge length. When subjected to uniaxial tension beyond the...

48 Cold drawing of wire and tube

As pointed out earlier, hot processing normally produces low-strength materials and uneven dimensional properties of the product. If high-quality fabricates are required, cold processing must follow the preliminary hot method of shape acquisition. In axisymmetric components, such as wire (rod) and seamless tubing, this is achieved by cold drawing the hot-finished product through a die (or a series of dies). This treatment imparts good mechanical properties and effectively regulates dimensional...

Nnc

Using equations (10.7) and (10.8), many series parallel resistive circuits can be reduced to a single effective resistance. Back calculation can then yield the current and potential differences across all the resistive elements which make up the circuit. 10.2.3 Electromotive force and potential difference In a metallic conductor which has a potential difference applied across opposite ends, free electrons are attracted to the more positive end of the conductor. It is this drift of electrons...

F 200

No 140 120 100 80 60 40 30 20 10 req Figure 2.11 SAE J200 ASTM D2000 classification for cross-linked elastomers. Whilst specific points are shown for clarity, there will be a spread for each rubber, the exact position depending on the grade of polymer and compounding formula used. (Reproduced by permission from Brydson, Rubbery Materials and their Compounds, Elsevier Applied Science)

R

Figure 2.43 Injection stretch-blow moulding process sequence, (a) Multiple injection moulding of amorphous preform, (b) Reheating stage, (c) Axial extension with telescopic mandrel, (d) Blow moulding both for making sheet (e.g. butyl rubber pond liners) and for impregnating fabrics (frictioning) with rubber prior to their use in the manufacture of such products as tyres, belting and hose. The rubber industry also uses a similar process for coating rubber onto fabric (skin coating). The calender...

T Buttery

8.15.1 Machining set-up and machining mechanisms 8 23 8 17 Machining with coated abrasives 8 27 8.17.1 Abrasive belts 8 27 8-iT2 Abrasive belt selection a 27 8.17.4 Factors controlling abrasive belt performance 8 28 8 20 2 Barrel polishing finishing 8 33 8-20.4 Barrelling compounds 8 33 8.21 Blasting processes 8 33 8.21.1 Blasting abrasives ft 34

163

Figure 5.28 Climb and upcut milling (a) climb (b) upcut Figure 5.28 Climb and upcut milling (a) climb (b) upcut The foregoing analysis provides useful indicators to the selection of cutting parameters, but it is unlikely that industry would adopt such a complicated method to calculate power requirements. It would be even more difficult to assess the power required for face milling where the work-cutter configuration can vary from total immersion of the cutter face to small arcs of contact in...

114 Microprocessor technology

In the manipulation of data within a computer, a two-state numbering system is used. This is termed the 'binary system' and is based on a simple ON OFF principle. For the semiconductor integrated circuits which make up the computer system. 5 V denotes ON, or logic level '1', while 0 V denotes OFF, or logic level '0'. In practice, a tolerance band is adopted with 2.4-5 V representing logic '1' and 0-0.8 V representing logic '0'. The microelectronic devices in the system handle the transfer of...

References

1 BRITISH STANDARDS INSTITUTION, BS 1296 Specification of single point cutting tools, Milton Keynes (1972) 2 STABLER, G. V., 'The fundamental geometry of cutting tools-, Proc. Inst. Mech. Eng., 165, 14 (1951) 3 CROOKALL, J. R. and RICHARDSON, D. B., 'Use of photographed orthogonal grids and mechanical quick stopping techniques in machining research'. Conference on Photography in Engineering, Institute of Mechanical Engineers, London (1969) 4 TRENT, E. M., Metal Cutting, Butterworth, London...

1980

Figure 1.41 High-temperature alloys of titanium used at present in production aeroengines years of development and temperature capability under optimum stress conditions. (Reproduced by permission of IMI Titanium Ltd) There are essentially five major groups of engineering applications of titanium process plant, marine condenser tubing, electrochemical fitments, aerospace frames and aeroengines. The most exciting applications are in the compressors (and other comoponents) of aircraft turbine...

029

* A vulcanisate of an unfilled natural rubber compound. 1 A vulcanisate. * A vulcanisate of an unfilled natural rubber compound. 1 A vulcanisate. unlike metal hardness measurements which are concerned with an irreversible plastic indentation. There is a good correlation between hardness and Young's modulus. The most widely used hardness test is that which yields 'international rubber hardness degrees' (IRHD). Also often quoted in the literature are British Standard (BS) hardness degrees and...

139 Hardened and tempered steels

At a carbon content above about 0.35 , or less when alloying elements are present, useful increases in strength may be obtained by transformation. The most important class of steel to which this procedure is applied is the 'hardened and tempered steels'. These will be chosen from AISI SAE 1035-4310 and BS 970 080A32-945A40. The steel heat treatments, quenching and tempering, austempering, martempering, annealing and isothermal annealing can be described most simply by means of the isothermal...

5 10 15 20 25

Bletween the tools and the work piece. This reduces the drawing load and or eliminates pick-up and chatter. However, practical difficulties are experienced in designing the plug and plug bar that will give the required resonance. If, however, the die is vibrated ultrasonically in the radial direction, rather than remains stationary as in a conventional drawing operation, a swaging effect is produced in the tube which, although conforming to the subdivision listed above, indicates that,...

H H

Ethylene is an example of a monomer and the process of joining up the molecules is known as polymerisation. In this case chemical reactions are initiated that lead to the double bonds opening up so that the particular process is often known as double-bond polymerisation. Many other important plastics such as polyvinyl chloride (PVC), polypropylene and polystyrene are made in a very similar way. In the above examples only one monomer is used to make the polymer and the products may be referred...

Ck K

Figure 10.81 Asynchronous 3-bit binary counter word which is representative of the number of input pulses applied at the input terminal. Using n flip flops, a total count of 2 can be made. Counting registers, or 'counters', may be synchronous in which the state changes in all the flip flops occur simultaneously, or asynchronous in which the state changes in various flip flops do not occur at the same time. Figure 10.81 illustrates an asynchronous, 3-bit binary counter composed of JK flip flops....

10

10 2 Basic electrical technology 1(1 3 1(1.2,I Flu* and potential difference lli 3 10,2 2 Simple resistive circuits HW 1(1,2.3 Electromotive force and potential 10.2 6 Double-subscript notation l(V4 10.2 7 Electrostatic systems 1W4 10.2-8 Simple capacitive circuits 10 5 10 2.1) Charging a capacitor HVG 10.2. It) Typts Of capacitor 10 b 10 2.11 Dielectric strength l(VG 10 2.12 electromagneiic syslcms 10 6 10.2.13 Magnetic field of a (oroid 10 7 10.2.17 Energy stored in an inductor 10 9 10.2.19...

16

Any deoxidising elements such as silicon or aluminium required to refine or degas the weld pool are contained in the solid wire and compositions of wires available are listed in BS 2901 Parts 1-520 for ferritic steels, austenitic stainless steels, copper and copper alloys, aluminium and aluminium alloys and magnesium alloys, and nickel and nickel alloys. Modes of metal transfer In MIG or MAG welding the operating conditions in terms of current and voltage determine the type of metal transfer...

1325Malleable iron

Malleable iron is cast with a white cementite structure which is converted to a steel-graphite composite by annealing. The requirement for the as-cast structure to be graphite free, limits the maximum section to about 38 mm and the general run of castings weigh under 5 kg and have a maximum section of 25 mm. There are three varieties. Whiteheart malleable This has a carbon content of about 3.5 which improves castability compared with the other varieties. Other alloying elements are silicon (0.6...

1987

Figure 3.3 Trends in the amount of various alloys used world-wide addition to reproducing the proper shape of a casting, they also reproduce the gating system and core prints. They are usually made of aluminium alloy or cast iron. They are used to reproduce small castings made in large batches. They are usually fixed to the cope and drag pattern plates. The cope and drag half moulds are prepared separately. This method is more expensive than those described above. However, it is necessary to...

29

5.5.2 Forces and power in milling operations Peripheral milling removes metal by means of teeth on the circumference of the cutter. It is seldom used to produce large flat surfaces, which are more effectively generated by face milling. Mostly, peripheral milling cutters are used for end milling slots or for producing slots or stepped surfaces by using one or more horizontally mounted side and face cutters or helical slab milling cutters. End milling seldom requires the rated power of the drive...

226 227 228

Stress-strain properties in tension 2 6 Modulus and hardness 2 7 Bulk modulus, Poisson's ratio and incompressibility IP Stress-strain properties of rubber in shear Stress-strain properties of robher in impression 2 7 Residence 2 9 Creep, set and dynamic properties 2 10 Non-rubbery properties (if I ethnical importance 2 10 2.5.3 Olher thermoplastics 2 25 2.5.4 Thermosetting plastics 2 25 2.6 Processing of bbers and plastics 2 26 2.6.2 Processing in the molten stale 2 26 2.6.3 Compression...

816 Coated abrasives

Coated abrasives give two-body abrasion and are constructed by applying a thin layer of abrasive to a suitable backing material. A wide range of backing materials is used including paper, waterproof paper, cloth, waterproof cloth, polyester cloth and combination backings. Figure 8.39 Structure of electrostatically coated abrasive cloth. 1, Backing 2, primary and secondary bond 3, grits Figure 8.39 Structure of electrostatically coated abrasive cloth. 1, Backing 2, primary and secondary bond 3,...

Ica

Visual inspection and repair of solder joints Figure 7.11 The steps involved in the mixed assembly of a double-sided printed circuit board (PCB) with surface-mount components (SMCs) on both sides (2) Ultraviolet radiation in an ultraviolet conveyor system the typical curing time may be about 3 min at 150 C for acrylic formulations. Solder paste or solder cream consists of a powdered solder alloy bound in a flux medium. The paste holds the surface-mount components in place until the solder is...

850

Abrasive belts and papers, sand blasting Three-body abrasion Loose abrasive in a carrier, such as oil or paraffin, is sandwiched between two surfaces (Figure 8.3(c)) and, as the surfaces move, the abrasive rolls between them occasionally removing material. Cutting rates are therefore low and the method is used mainly to lap in mating surfaces or to produce very high quality finishes. When geometric shape is not important, a cloth may be used to carry the abrasive slurry this method is widely...

0 V

ON time 0.693(1 + R2)C OFF time 0.693(f 2)C Figure 10.85 The 555 timer in astable operation Obviously the ON time can only be equal to, or greater than the OFF time. The output signal, however, can always be inverted if in a particular application short duration positive pulses are required. The maximum operating frequency for the 555 timer is about 500 kHz and the minimum frequency, limited by the leakage of the capacitor, is about one cycle per several hours. Alternative pulsed output...

46 Forging operations

Forging, one of the oldest known metal-forming operations, relies entirely on the application of compressive forces to effect the change of shape. In its simplest form, forging is used to preform a billet by changing its dimensions (preparatory to further shaping), and in its more sophisticated form it produces complex shapes to a very high degree of accuracy. Depending on whether the operation is carried out hot, warm or cold, forging affects the structure and properties of the forged...

125Drawbacks of the classical procedure

Application of the procedures outlined above guarantees success if followed logically and completely and if design, operating and material parameters are thoroughly understood. This is seldom the case in practice. Designs cannot always be evaluated precisely, material properties are seldom specified fully, and it is impossible to predict exactly what an operator will do. In most cases the classical method requires a considerable amount of mechanical-property evaluation, possibly materials and...

115 Fatigue

S-N curve The graphical relationship between the stress 5 and the number of cycles N required to cause failure of a material in a fatigue test. This depends on the mean stress, frequency and shape of the stress cycle, the temperature and the environment, all of which should be specified. Note this applies to high cycle fatigue. High strain fatigue is strain, not stress, related and the plastic strain per cycle resulting in failure ep is inversely proportional to N1 2 for almost all engineering...

85 Balancing and dressing

To ensure safe operation and to achieve the best quality of surface on the work piece, the wheel must be balanced and dressed. Several methods of balancing are available static, dynamic and automatic balancing self-balancing. In many applications, static balancing (which is simple and cheap) is quite adequate. With static balancing the balance weights are usually incorporated in the wheel flanges. Initially, the balance weights are set opposite each other, the wheel assembly is fitted to the...

10424 Speed control of induction motors

Under normal circumstances, the running speed of an induction motor will be about 94-98 of the synchronous speed, depending on the load. With the synchronous speed given by equation (10.118), it is clear that the speed may be varied either by changing the frequency of the supply current, or by changing the number of poles. 10.4.24.1 Change of supply current frequency Solid-state variable-frequency drives first began to appear in 1968. They were originally applied to the control of synchronous...

55

* Reproduced by permission of North Holland Publishing Co. * Reproduced by permission of North Holland Publishing Co. Figure 1.61 Strength-to-density ratio for several classes of high temperature materials with respect to temperature. (Reproduced by permission of Metals and Materials) Figure 1.61 Strength-to-density ratio for several classes of high temperature materials with respect to temperature. (Reproduced by permission of Metals and Materials) Figure 1.62 Three-dimensional orthogonal...

T6

* Reproduced by permission of the heirs of Dr E. A. West. i As there are variations depending on form and thickness, details must be obtained from the relevant British Standard. * Reproduced by permission of the heirs of Dr E. A. West. i As there are variations depending on form and thickness, details must be obtained from the relevant British Standard. Initial guide to selecting aluminium alloys for use at elevated temperatures'

1400910

All phases are constituents but some constituents are not necessarily phases, e.g. pearlite is a constituent but it consists of the phases cementite and ferrite in a particular arrangement. The phase diagram represents the phases present, at given temperatures, which are in equilibrium with each other. Equilibrium is attained by slow heating or cooling to allow constitutional changes to be completed. The iron-carbide phase diagram (Figure 1.12) shows the effect of...

R Goss

9.1.1 Automatic insertion of fasteners 9 3 9.1 A Load sensing in bolts 9 5 9. .(p Threaded inserts and studs for plaSliM 9 7 9.1.9 Stiff nuts 9 7 91-llJ Washers 9 7 4.1.11 Spring steel listeners 9 8 9.1.13 Self-sealing fasteners 9 8 9.1.15 List of suppliers of fasteners 9 JO 9.2 Welding, soldering and brazing 9 11 9-2.2 Soldering and brazing 9 25 9.2.3 Productivity and welding economics 9 26 9.3.2 Modern engineering adhesive* by category 9 27 9.3.3 Designing with sdhesives 9 2ft 9-3,4 Anaerobic...

7

Figure 9.18 Welding circuit for manual metal arc welding welding power source, such as an a.c. transformer or a d.c. generator (Figure 9.18). The other terminal of the power source is connected to the work piece via the earth return or the ground cable, so that when the end of the electrode is placed in contact with the work piece, electric current flows through the circuit. By withdrawing the tip of the electrode to about 3 mm from the work piece, an arc will be struck and current will...

M

Figure 9.16 Examples of welded joints Manual metal arc welding, referred to as 'shielded metal arc welding' in the USA, is the most widely used welding process and accounts for approximately 50 of all the welding carried out in the world today. With this process, welding is carried out with flux coated electrodes which are connected via an electrode holder and length of cable to one terminal of a Electrode holder Power source and controls

Q

Figure 9.14 Blind rivets, (a) Break-stem mandrel, (b) Pull-through mandrel, (c) Break-stem mandrel (open end), (d) Break-stem mandrel (closed end), (e) Threaded mandrel, (f) Drive pin. (g) Chemical expanded (open end), (h) Chemical expanded (closed end) 9.1.15 List of suppliers of fasteners Armstrong Screws and Fixings, 72 Great Barr Street, Birmingham B9 4BJ, UK Bollhoff Fastenings Ltd. Midacre, The Willenhall Estate, Willenhall WV13 2JW, UK British Industrial Fasteners Federation, Queens...

U

Figure 9.11 Various types of plastics fasteners, (a) Dart-type clip, (b) Nylon expansion nut. (c) Plastirivet. (d) Rachet rivet, (e) Plastics rivet, (f) Triploc rivet Figure 9.11 Various types of plastics fasteners, (a) Dart-type clip, (b) Nylon expansion nut. (c) Plastirivet. (d) Rachet rivet, (e) Plastics rivet, (f) Triploc rivet 120 countersunk head Head dia. 2 x shank dia. Rounded countersunk head 60 Head dia. 1.5 x shank dia.

141 Copper and its alloys

Copper is basically more expensive than iron but has important advantages for special applications, the most significant of which is conduction. The electrical conductivity of pure copper is superior on a volume basis to all metals other than silver, and on a weight (and specific cost) basis to all metals other than aluminium. The same relationships apply to its thermal conductivity. Both properties are reduced by alloying, but the conductivities of copper alloys are superior to those of...

1010

Cast blades Vacuum casting has provided an alternative manufacturing route. Problems met with in the earlier alloys included cracking due to the separation of massive carbides on solidification and the formation of cr-like intermetallic compounds. However, in one specific alloy, IN100, up to 70 y' fraction was achieved. This had the immediate effect of eliminating the need for solid solution strengthening so that a low density high creep resistance material became available. Early casts of...

1020

8.20.2 Barrel polishing finishing Barrelling is an inexpensive method of processing small to medium sized products in bulk, giving considerable savings on manual methods. Applications include cleaning small castings, deburring, and polishing prior to plating. Barrels may be rotated vertically, horizontally or obliquely. Horizontal closed barrels can also be designed to reciprocate, which is advantageous when treating recessed components. Facilities must be provided for loading and unloading the...

831 Grit size

The abrasive grains making up the wheel are accurately graded and a wheel will usually contain only one size of grit. Wheels having a coarse grit size are used for roughing operations where rapid metal removal is required and surface finish is not critical. Finer grit sizes are used for finishing operations, giving superior surface finish but with a reduction in metal removal rate. The relationship betwen the type of work and the grit size is shown in Table 8.2.

25 Survey of commercial plastics materials

As with the rubbery materials the market for plastics materials is dominated, in tonnage terms, by a small number of polymers. Today, four polymers, namely polyethylene, polypropylene, PVC and polystyrene, account for about 80 of the total market tonnage. There are additionally several hundred other materials which could be classified as plastics that are on the market. Most of these have been considered at greater depth by the writer elsewhere3 and this section can only give an outline...

911 Automatic insertion of fasteners

Depending on specific applications, most fasteners in use today can be installed automatically and, since some 80 of the total cost of fastening is on-assembly cost, a mere saving of 10 in assembly costs is more significant than a 40 saving in piece part costs. Nevertheless, 80 of manufacturers assembling products with automated or robotic screwdriving equipment claim to have difficulties with their fasteners. This is the finding of a recent research survey carried out for European Industrial...

0935

Lubrication, the range of processes materials, etc., will often call for further modifications to be made and, consequently, for the extension of the laborious and unreliable testing technique. In addition, the lack of appreciation of the fundamentals of the mechanics of metal flow and deformation in a given process very often results in the adoption of tool profiles which, although apparently working, impose unduly severe conditions. Tool profiles, so established, can become complicated and...

Vs

1940 1950 1960 1970 1980 1990 2000 Approximate year available Figure 1.50 Comparative 1000 h rupture strengths of nickel alloy gas turbine blading materials produced by a variety of techniques Figure 1.51 Increase in temperature capability for turbine-blade alloys based on creep rupture in 1000 h at 150 MPa. (Reproduced by permission of Metals and Materials) MONEL alloy 400 63.0 0.15 1.0 MONEL alloy 411) 66.0 0.2 0.8 MONEL alloy K-500 63.0 0.15 1.5 HASTELLOY alloy B Bal. 0.09 1.0 VO.3 HASTELLOY...

2l92

LM10 TB, LM12 TF, LM13 TF, L35, 2L92 5083 0, 5251 0 H4-H8, 5454 0 H2-H8, 6063 T6, 6082 T6, 7075 T6 2014 T6, 2618 T6, 3103 H8, 5083 0, 5251 0 H4-H8, 5454 0 H2-H4, 6082 T6, 7075 T6 2618 T6, 5083 0, 5251 H4-H8, 5454 0 H2-H4 2014 AFT, 2618 T6, 5083 0, 5251 H4-H8, 5454 0 H2-H4,6063 T6,6082 T6,7075 T6 2014 T6, 2618 T6, 5083 0, 5251 H4-H8, 5454 H2-H8, 7075 T6 2618 T6 * Reproduced by permission of the heirs of Dr E. A. West. t Based, in general, on static tests undertaken at temperature after soaking...

200250 100 150 200 250

LM4, LM5, LM6, LM10 TB, LM12 TF, LM13 TF, LM25 TF, L35, 2L92 TF LM4, LM5, LM6, LM10 TB, LM12 TF, LM25 TF, L35, 2L92 1200 H8, 2014 T6, 2618 T6, 3103 H4-H8, 5083 0, 5251 0 H4-H8, 5454 0 H2-H4, 6063 T6, 6082 T6, 7075 T6 1200 H8, 2014 T6, 2618 T6, 3103 H4-H8, 5083 0, 5251 0 H4-H8, 5454 0 H2-H4, 6063 T6, 6082 T6, 7075 T6 2014 T6, 2618 T6, 5083 0, 5251 0 H4-H8, 5454 0 H2-H4, 7075 T6 5083 0, 5454 0 H2-H4, 6082 T6, 7075 T6 LM4, LM5, LM6, LM10 TB, LM12 TF, 1200 H8, 2014 T6, 2618 T6, 3103 H8, LM5, LM10...

Htb1

Gl, LG2, LG4, ABl, AB2 HTB1, LG2, LG4 * Reproduced by permission of the heirs of Dr E. A. West. Table 1.24 Initial guide to selection of copper and copper alloys for applications at raised temperatures* Superheated steam valves and fittings Spot, seam and flash butt welding electrodes and dies CA103, CA104, CA105 CC101, CC102 C108 CC101, CC102 CC101, CC102 C108, CB101, CC101 A most important point to consider in the selection of aluminium is the cyclical price variation. The supply of aluminium...

Bibliography

Bibliography For Metal Forming Process

ALTING, L., Manufacturing Engineering Processes, Marcel Dekker, New York (1982) AVITZUR, B., Metal Forming Processes and Analysis, McGraw- Hill, New York (1968) BLAZYNSKI, T. Z., Metal Forming Tool Profiles and Flow, Macmillan, London (1976) BLAZYNSKI, T. Z., Applied Elasto-Plasticity of Solids, Macmillan, London (1983) BLAZYNSKI, T. Z., Design of Tools for Deformation Processes, Elsevier Applied Science, London (1986) BLAZYNSKI, T. Z., Plasticity and Modern Metal-Forming Technology, Elsevier...

Bs 1471 Bs 1472

Aluminium and aluminium alloy ingots and castings Wrought aluminium and aluminium alloys for general engineering purposes plate, sheet and strip Drawn tube Bars, extruded round tubes and sections Anodic oxide coatings on wrought aluminium for external architectural applications Anodic oxidation coatings on aluminium Methods for crack opening displacement (COD) testing Code of practice for the design of aluminium structures See also BS L series and DTD specifications for defence materials.

814 Honing practice

Honing uses the complete range of abrasive materials including silicon carbide, aluminium oxide, diamond and cubic boron nitride (CBN). In the honing process, the abrasive is in continuous contact over a large area of the component. In order to achieve both self-sharpening and free cutting requires very careful selection of the abrasive type, grit size and bond hardness. The combination of grit and bond should satisfy the above requirements and also give an economic abrasive life. The honing...

92 Welding soldering and brazing

Welding is used for joining metals so that the physical and mechanical properties of the parent metal are reproduced in the joint. The integrity of a welded component, which has metallurgical continuity across the joint, is also characterised by properties such as pressure tightness, or heat and corrosion resistance. These properties have contributed to the rapid development, both technical and economic, in all fields including nuclear power, chemical engineering, bridge building, offshore...

630

Nearest equivalent specifications BS 1449 1970 284S16 540 1240 Readily hardens by cold working. Structural steels for applications where high strength is required. Nearest equivalent specifications BS 1449 1970 301S21 510 790 For spoons and forks, holloware, architectural and shop fittings, domestic catering, food manufacturing, dairy and brewery equipment. Nearest equivalent specifications BS 970 1983 302S25 Bs 1449 1970 302S17, 302S25 510 790 A general purpose austenitic free-cutting steel....

467 Orbital forging

The orbital forging process is intended to allow smaller machines to be used for suitable forging operations. This process is based on the simple concept that the axial force required to effect a desired deforming zone between the platens is confined to a small region. The plastic zone is then moved through the work piece, thus resulting in progressive deformation. The plastically deforming region is formed by initially indenting with a conical platen into the work piece which is supported by a...

3

Effective radius when roll is slipping faster than tube Effective radius when tube is slipping faster than roll Figure 4.51 Effective radius in roll design role in the design and operation of reducing mills and depends on the rolling condition. No-stretch conditions prevail when a tube passes through a single stand, so that its diameter is reduced without any external axial forces being applied to it the thickness also increases. In this case, where the change in wall thickness occurs purely as...

1318 Tool steels

The name 'tool steels' BS 4659 1971 and AISI SAE 'Tool steels' covers a wide variety of steels used for forming and cutting materials which have as essential properties high hardness, resistance to wear and abrasion and adequate toughness. There are, or have been, some 82 AISI standard steels, 25 BS steels and many non-standard steels, but it should be possible to meet almost all requirements from the 10 steels listed here. Carbon steels are used for hand tools and other applications where high...

22

0.03 max. 17 13.5 4.5 Resistance to strong organic acids at elevated temperatures. Increased reistance to pitting. Applicable below 300 C. Resists intergranular attack. Weldable for most applications water jets . Their metallurgy is similar to that of high speed steels. A recommended steel is AISI H13 BS 4659 BH13 this steel has the highest and deepest hardness of the hot work steels. Cold work steels are used for forming cold materials and resistance to abrasive wear is of highest importance....

138 Electrical steels

Electrical steels comprise a class of steel strip which is assembled and bolted together in stacks to form the magnetic cores of alternating current plant, alternators, transformers and rotors. Its essential properties are low losses during the magnetising cycle arising from magnetic hysteresis and eddy currents, high magnetic permeability and saturation value, insulated surfaces, and a low level of noise generation arising from magnetostriction. These parameters are promoted by maintaining the...

134 Mechanical working of metals

This topic is included for convenience in this section on ferrous metals, but is more widely applicable. A metal is worked mechanically either to generate a shape more economically than can otherwise be obtained or to provide improved properties in strength, ductility and or fatigue not creep for which a cast structure is superior . The improvement in properties may, overall, be directional to resist a directional stress system, or statistical to ensure that a lower percentage of components...

Abc

Figure 1.24 Isothermal diagrams showing the heat treatment of steel, a Quenching and tempering to give tempered martensite. b Austempering to give lower bainite. c Martempering to give tempered martensite. d Annealing to give ferrite and peariite. e Isothermal annealing to give ferrite and peariite Figure 1.24 Isothermal diagrams showing the heat treatment of steel, a Quenching and tempering to give tempered martensite. b Austempering to give lower bainite. c Martempering to give tempered...

434

C 0.12 0.20 Cr 16.0 18.0 Ni 2.00 3.00 C 0.10 max. Cr 16.0 18.0 Mo 0.90 1.30 Ni 0.50 max. 850 1000 General engineering. Pump and valve parts in contact with non-ferrous metals or graphite packing . Nearest equivalent specifications BS 970 431S29 Ferritic stainless. Motor car trim. Nearest equivalent specifications BS 1449 434S19 Free machining versions of 13 Cr steels are available to BS 970 416S21, 416S29, 416S37. than nickel. These steels can be cold worked to higher strengths than the '300'...

Bs970 347s17 Equivalent Specification

Cr 16.5 18.0 Ni 10.0 13.0 Mo 2.25 3.00 C 0.07 max. Cr 16.5 18.5 Ni 10.0 13.0 Mo 2.25 3.00 N 0.25 max. C 0.03 max. Cr 17.5 19.5 Ni 14.5 17.0 Mo 3.00 4.00 C 0.06 max. Cr 17.5 19.5 Ni 12.0 15.0 Mo 3.00 4.00 C 0.08 max. Cr 16.5 18.0 Ni 11.0 14.0 Mo 2.25 3.00 Ti 4 x C 0.60 C 0.08 max. Cr 17.0 19.0 Ni 9.00 11.0 Ti 5 x 00.10 C 0.08 max. Cr 17.0 19.0 Ni 9.00 11.0 Ti 5 x C 0.70 C 0.12 max. Cr 17.0 19.0 Ni 8.00 11.0 Ti 5 x C 0.90 S 0.15 0.30 C 0.08 max. Cr 17.0 19.0 Ni 9.00 11.0 Nb 10 x a...

Iiiiii1

Figure 1.20 Continuous cooling time-temperature-transformation diagrams, a Applicable to forgings, plates and sections, b Applicable to heat treatment of bars These products exemplify more than any others the quality improvements that the improvements in steelmaking described in Section 1.3.3 have produced in tonnage steels. 1 lower maximum sulphur levels as low as 0.008 2 improved deoxidation with low inclusions and controlled morphology 3 very low hydrogen levels resulting from vacuum...