It is tested by pressing a hard object (ball, diamond tip) into the test material and measuring the size (depth, area) of the indentation. Based on the BHN determined in this problem, estimate the tensile strength of the steel.
4 PHYSICAL PROPERTIES OF MATERIALS
An electrolyte is an ionized solution capable of conducting electric current by the movement of ions. There are a total of 12 correct answers in the following multiple choice questions (some questions have multiple answers that are correct).
5 DIMENSIONS, TOLERANCES, AND SURFACES
Processes that produce poor surfaces include: sandblasting, hot rolling, sawing and thermal cutting (eg flame cutting). There are a total of 19 correct answers in the following multiple choice questions (some questions have multiple answers that are correct).
6 METALS
Various alloying elements (Cr, Mo, V) form hard carbides with C, which increases wear resistance. The three basic methods are: (1) alloying to form solid solutions and two-phase structures that are stronger than the elemental metals; (2) cold working, in which the stress-hardened metal is stronger and harder than the unstressed metal; and (3) heat treating - most commercial heat treatments are designed to increase the strength of the metal.
7 CERAMICS
The functions of the additional ingredients include: (1) acting as a flux (promoting fusion) during heating; (2) increasing the fluidity in the molten glass during processing; (3) delay. There are a total of 18 correct answers to the following multiple choice questions (some questions have multiple correct answers).
8 POLYMERS
Fillers are added to increase strength or simply to reduce the cost of the polymer. (c) sum of the molecular weights of the mers in the molecule; or (d) none of the above.
9 COMPOSITE MATERIALS
Three factors are given in the text: (1) the materials of the components; (2) the geometric shapes of the components - in particular the reinforcing phase - and the resulting structure of the material; The rule of mixtures applies to certain properties of composite materials; it states that the property value is a weighted average of the property values of the components, with the weighting being based on the proportions of the components in the composition.
10 FUNDAMENTALS OF METAL CASTING
Find: (a) the theoretical velocity and rate of flow at the bottom of the downspout; (b) the total volume of the mold;. Determine: (a) the mold constant in Čvorin's rule; and (b) dimensions and (c) total curing time of the lighter casting.
11 METAL CASTING PROCESSES
Which one of the following casting metals is most important commercially? (a) aluminum and its alloys, (b) bronze, (c) cast iron, (d) cast steel, or (e) zinc alloys
If the rotation speed of the pipe = 700 rev/min, (a) determine the G-factor on the molten metal. Suppose the inner wall of the casting is straight from top to bottom (an approximation of the parabolic shape).
12 GLASSWORKING
The glass is heated to a temperature higher than the annealing temperature, and the surfaces are then cooled with air jets to cool and harden while the interior of the piece remains plastic; as the interior cools and contracts, it compresses the previously hardened surfaces, hardening it. The following multiple choice questions have a total of 10 correct answers (some questions have more than one correct answer).
Drag current is the forward movement of the melt caused by the Archimedean screw principle in the vessel. A thermoforming die with a convex shape is called one of the following (may be more than one). The viscosity of the polymer melt is 75 Pas and the head pressure in the vessel is 4.0 MPa.
14 RUBBER PROCESSING TECHNOLOGY
Three examples: (1) no draft is needed in the mold removal section; (2) holes must be formed in rubber parts and not machined, while holes can be machined or formed in a plastic part; and (3) screw threads are not commonly used in rubber parts. There are a total of 11 correct answers in the following multiple choice questions (some questions have multiple answers that are correct). To achieve a perfect score on the quiz, all correct answers must be given, as each correct answer is worth 1 point.
15 SHAPING PROCESSES FOR POLYMER MATRIX COMPOSITES
Filament winding is a process in which resin-impregnated continuous filaments are wound around a rotating mandrel with the internal shape of the FRP product; the resin is cured and the mandrel is removed. Pultrusion is a process in which continuous fibers are immersed in a resin and pulled through a forming die (sort of like an extrusion die) where the resin cures. Pulforming is pultrusion with the added operation of a shape change in length (straight length becomes curved) and cross-section (various cross-sections along the length).
16 POWDER METALLURGY
Our approach to determining the packing factor will consist of: (1) finding the volume of the spheres and portions thereof contained in the cell, and (2) finding the volume of the unit cell cube. Note that the diagonal of any face of the unit cell contains one full diameter (the sphere in the center of the cube face) and two half diameters (the spheres at the corners of the face). Determine: (a) the most suitable press direction, (b) the required press tonnage to perform this operation, and (c) the final weight of the part if the porosity is 10%.
17 PROCESSING OF CERAMICS AND CERMETS
Because water is not usually one of the ingredients in the new ceramic during molding. Because the requirements for the strength of the finished product are usually more demanding for new ceramics. There are a total of 15 correct answers in the following multiple choice questions (some questions have more than one correct answer).
18 FUNDAMENTALS OF METAL FORMING
Determine the average yield stress that the metal has. experiences when subjected to a stress equal to the strength coefficient K. 18.7 Determine the value of the strain hardening exponent for a metal that causes the average yield stress to be 3/4 of the ultimate yield stress after deformation. It is subjected to a tensile test in which the grips holding the end of the test piece are moved at a relative speed = 0.1 m/s. Plot the strain rate versus length as the sample is pulled to a length = 8.0 inches.
19 BULK DEFORMATION PROCESSES IN METALWORKING
Determine: (a) the maximum possible draft, (b) the associated true strain, and (c) the maximum speed of the rolls for the operation. Solution: (a) Assumption (same as in the previous problem): the maximum possible draft is determined by the rolling mill's capability force and not by the coefficient of friction between the rolls and the work. The operation is carried out cold and the metal strength coefficient K = 26,000 lb/in2 and the strain hardening exponent n = 0.20.
20 SHEET METALWORKING
A major technical problem in pipe bending is the collapse of the pipe walls during the process. While the operation in Problem 20.23 was not feasible, the operation in this problem appears feasible. A2 = the length of the bottom quarter of the circle multiplied by the circumference of the circle.
21 THEORY OF METAL MACHINING
Using the appropriate specific energy value from Table 21.3, determine the maximum power that can be set for this operation. From the unit horsepower values in Table 21.3, determine: (a) the horsepower consumed by turning; (b) the horsepower to be generated by the lathe. From the specific energy values in Table 21.3, determine: (a) the cutting power and (b) the gross turning power, in Watts.
22 MACHINING OPERATIONS AND MACHINE TOOLS
Determine (a) the time required to rotate the cone and (b) the rotational speeds at the beginning and end of the cut. The rotational speed at the beginning of the cut = 30 rpm. and then continuously increased to maintain a constant cutting speed. The helical cutter, which has a diameter of 2.5 and eight teeth, is set up to overhang the width of the part on both sides.
23 CUTTING TOOL TECHNOLOGY
Dry machining is being considered by machine shops because of certain problems inherent in the use of cutting fluids. (a) What are those problems associated with the use of cutting fluids? (b)
The values should be approximately the same as those obtained in part (c) below. a) Determine the parameters n and C in the Taylor tool life equation. Units for the Taylor equation are min. for tool life and m/min for cutting speed. Units for the Taylor equation are min. for tool life and ft/min for cutting speed.
24 ECONOMIC AND PRODUCT DESIGN CONSIDERATIONS IN MACHINING
Based on this information and the machining data given in Table 24.1, determine the cutting speed you would recommend for the following work materials if the desired tool life is 30 min: (a) C1008 low carbon steel low with 150 Brinell hardness, b) 4130 steel with 190 Brinell hardness and (c) B1113 steel with 170 Brinell hardness. The effect of the cutting fluid can be either increased cutting speed (at the same tool life) or increased tool life (at the same cutting speed). a). The ideal roughness is given by Eq. 24.1) and an adjustment will need to be made using Figure 24.2 to convert the current 63 µin roughness to an ideal roughness, taking into account the material and cutting speed.
25 GRINDING AND OTHER ABRASIVE PROCESSES
Determine: (a) the average length per chip, (b) the metal removal rate, and (c) the number of chips formed per unit of time for the part of the operation where the wheel is engaged in the work. Determine the flow rate for cylindrical workpieces that are 25.0 mm in diameter and 175 mm long. Determine the flow rate for cylindrical workpieces that have the following dimensions: diameter = 1.25 in and length = 8.0 in.
26 NONTRADITIONAL MACHINING AND THERMAL CUTTING PROCESSES
The material to be cut is pure aluminium, the specific removal rate C of which is shown in Table 26.1. efficient, determine the metal removal rate at 3/hr. Solution: As shown in Figure 26.9(a), the surface finish in EDM can be improved by reducing the discharge current and increasing the discharge frequency. Determine: (a) the metal removal rate in mm3/min, (b) the time required to machine to the specified depth, (c) the required opening dimensions in the cut and peel mask to achieve the size of desired part pocket.
27 HEAT TREATMENT OF METALS
Selective surface hardening methods include: flame hardening, induction hardening, high frequency (HF) resistive heating, electron beam (EB) heating and laser beam (LB) heating. The following multiple choice questions have a total of 14 correct answers (some questions have more than one correct answer). For each question, each omitted or incorrect answer lowers the score by 1 point, and each additional answer beyond the required number of answers lowers the score by 1 point.
28 CLEANING AND SURFACE TREATMENTS
There are a total of 16 correct answers in the following multiple choice questions (some questions have multiple answers that are correct).
29 COATING AND DEPOSITION PROCESSES
In PVD, the coating vapor is synthesized by heating the coating material and allowing it to condense as a thin film on the surface of the workpiece. The following multiple choice questions have a total of 17 correct answers (some questions have more than one correct answer). What is the value of the gold that will be plated if one ounce of gold is valued at $300.
