12 Fundamentals of forming processes

1. Which process was one of the earliest methods used to shape metals?. A. Casting molten metal into molds. B. Forging metal by striking it with stones. C. Welding metal pieces together. D. Cutting metal with sharp tools.

2. What characterizes elastic deformation?. A. Permanent shape change. B. Increase in hardness. C. Recovery of the original shape after unloading. D. Formation of new grains.

3. What must occur for plastic deformation to begin?. A. The melting point must be reached. B. The elastic limit must be exceeded. C. The material must be cooled. D. The grain boundaries must disappear.

4. Which forming process is dominated by tensile stresses?. A. Rolling. B. Extrusion. C. Drawing. D. Forging.

5. Which product is commonly obtained through rolling?. B. Powdered metal components. A. Sheet metal. C. Cast iron blocks. D. Welded structures.

6. The crystalline structures formed during solidification are called: A. Fibers. B. Polymers. C. Grains. D. Matrices.

7. Which type of stress is responsible for atomic slip during plastic deformation?. A. Tensile stress. B. Shear stress. C. Thermal stress. D. Compressive stress.

8. Which defect plays a key role in enabling plastic deformation?. A. Vacancies. D. Dislocations. C. Twins. B. Interstitial atoms.

9. What happens to dislocations as plastic deformation increases?. A. They disappear. B. They become more organized. C. They multiply and entangle. D. They convert into grain boundaries.

10. Strain hardening results in: A. Higher ductility and lower strength. B. Higher strength and lower ductility. C. Lower strength and higher ductility. D. No change in mechanical properties.

11. What process removes dislocations and forms new grains?. B. Casting. A. Recrystallization. C. Machining. D. Strain hardening.

12. Annealing typically heats a metal to what percentage of its melting point?. A. 5%–10%. B. 10%–20%. C. 30%–50%. D. 70%–90%.

13. Residual stresses are: A. Stresses caused only by thermal expansion. B. Stresses that remain after external loads are removed. C. Stresses applied during machining. D. Always harmful and must be eliminated.

14. During plastic deformation, grains in a polycrystalline metal: A. Melt and reform. B. Break into smaller grains. C. Elongate in the direction of deformation. D. Remain unchanged.

15. Which manufacturing method produces isotropic grain structure?. A. Forging. B. Rolling. C. Turning. D. Casting.

16. Why does forging improve fatigue resistance?. A. It eliminates all grain boundaries. B. It aligns grains along stress directions. C. It increases the melting point. D. It removes residual stresses.

17. What negative effect does machining have on grain structure?. A. It increases ductility. B. It cuts grain boundaries, reducing strength. C. It aligns the grains. D. It strengthens the material.

18. The variation of material properties depending on direction is called: A. Elasticity. B. Homogeneity. C. Isotropy. D. Anisotropy.

19. What causes preferred orientation in rolled sheets?. A. Random grain growth. B. Chemical reactions during rolling. C. Alignment of grains during deformation. D. Uniform heating.

20. Which process combines multiple types of stresses such as tension, compression, and bending?. A. Punching. B. Rolling. C. Deep drawing. D. Drawing.

21. Which mechanical properties are most relevant for manufacturing processes?. A. Density, color, and conductivity. B. Strength, hardness, toughness, and ductility. C. Magnetism, density, and melting point. D. Elasticity, porosity, and corrosion resistance.

22. What do stress–strain curves represent?. B. The relationship between temperature and hardness. A. The relationship between applied stress and resulting deformation. C. The relationship between mass and volume. D. The relationship between force and time.

23. Which test is most commonly used to obtain stress–strain curves?. A. Torsion test. B. Impact test. C. Uniaxial tension test. D. Fatigue test.

24. In a uniaxial tension test, how is the specimen typically shaped?. A. Rectangular with sharp edges. B. Cylindrical with threaded ends. C. Hollow tube with welded ends. D. Square bar with rounded corners.

25. What happens when the applied stress exceeds the yield strength?. A. The material melts. B. The material fractures immediately. D. Permanent plastic deformation begins. C. The material becomes more elastic.

26. What is the Ultimate Strength in a stress–strain curve?. B. The stress at which the material begins to melt. A. The maximum nominal stress before necking begins. C. The stress at which elastic deformation ends. D. The stress required to fracture the specimen.

27. What phenomenon occurs after the Ultimate Strength is reached?. A. Homogeneous deformation. B. Increase in cross‑sectional area. C. Formation of a neck in the specimen. D. Increase in nominal stress.

28. Young’s modulus is defined as: A. The ratio of stress to strain in the plastic zone. B. The ratio of strain to stress in the plastic zone. C. The ratio of stress to strain in the elastic zone. D. The ratio of force to displacement.

29. Why is nominal stress considered misleading at large deformations?. A. It ignores the applied force. B. It uses the initial cross‑sectional area instead of the instantaneous one. C. It assumes the material is perfectly elastic. D. It does not consider temperature effects.

30. True strain is preferred over nominal strain because: A. It is always smaller. B. It is expressed as a percentage. C. It remains constant during deformation. D. It is additive and better represents physical behavior.

31. In a hypothetical compression to zero length, true strain becomes: A. Zero. B. Infinite. C. Negative one. D. Undefined.

32. Hollomon’s equation relates true stress to: A. Temperature. B. True strain. C. Elastic modulus. D. Nominal strain.

33. Increasing temperature generally causes: A. Higher strength and higher strain hardening. B. Lower ductility and higher strength. C. Higher ductility and lower strength. D. No change in mechanical properties.

34. Which behavior corresponds to a material that deforms plastically at constant stress?. A. Perfectly elastic. B. Elastic with strain hardening. C. Elastic and perfectly plastic. D. Brittle elastic.

35. The Tresca criterion is based on: A. Maximum shear stress. B. Total strain energy. C. Temperature‑dependent modulus. D. True strain additivity.

36. In a uniaxial tensile test, the principal stress used in Tresca’s criterion is: A. The compressive stress. B. The shear stress. C. The first principal stress. D. The third principal stress.

37. The Von Mises criterion is based on: B. Maximum normal stress. A. Shear strain energy. C. Tensile modulus. D. True stress only.

38. What is a disadvantage of the uniaxial tension test?. A. It cannot measure force. B. It produces too much elastic deformation. D. The specimen breaks before large plastic strains can be measured. C. It requires extremely high temperatures.

39. What shape does a specimen tend to acquire during a uniaxial compression test due to friction?. A. Conical shape. B. Barrel shape. C. Cylindrical shape. D. Cubic shape.

40. Which test is most suitable for studying large plastic deformations, such as those in hot forming?. A. Uniaxial tension test. B. Plane compression test. C. Torsion test. D. Impact test.

41. Which of the following is a characteristic of cold working?. A. High ductility. B. Low strain hardening. D. High strength and hardness. C. High dimensional inaccuracy.

42. Why are higher forces required in cold working?. A. The material becomes softer. B. The material has higher strength at low temperatures. C. The grain structure becomes isotropic. D. The melting point decreases.

43. Which heat treatment is sometimes needed after cold working to restore ductility?. A. Quenching. B. Tempering. C. Annealing. D. Normalizing.

44. What is a disadvantage of cold working?. A. Poor surface finish. B. High energy consumption. C. Low dimensional accuracy. D. Limited achievable strain due to low ductility.

45. What is a major advantage of hot working?. A. Increased strength and hardness. B. Zero strain hardening exponent. C. Excellent dimensional accuracy. D. No risk of oxidation.

46. Which of the following is a disadvantage of hot working?. A. High strain hardening. B. Poor surface finish and oxidation. C. High anisotropy. D. Very low energy consumption.

47. What is a key characteristic of warm working?. A. It requires the highest forces. B. It produces isotropic grain structures. C. It occurs between cold and hot working temperature ranges. D. It always requires annealing.

48. Why can warm working avoid the need for annealing?. B. It increases strain hardening. A. It reduces required forces and improves ductility. C. It eliminates grain boundaries. D. It produces perfect surface finishes.