13 Metal rolling

1. The earliest evidence of manual rolling dates back to: A. Ancient Egypt. B. The Roman Empire. C. The Sumerians in the 7th century BCE. D. Medieval Europe.

2. Early manual rolling was mainly used to produce: A. Steel beams. B. Gold sheets and small rods. C. Iron rails. D. Aluminum foil.

3. Modern rolling began in 1783 with a patent for producing: B. Steel plates. A. Iron bars using grooved rolls. C. Wire rod. D. Seamless tubes.

4. The industrial revolution boosted rolling due to: A. The invention of hydraulic presses. B. The introduction of steam engines. C. The discovery of stainless steel. D. The development of welding.

5. In the 20th century, steam engines in rolling mills were replaced by: A. Water wheels. B. Combustion engines. C. Electric motors. D. Pneumatic systems.

6. The main objective of flat rolling is to reduce: A. Width. B. Length. C. Thickness. D. Temperature.

7. Flat rolling represents approximately what percentage of rolling production?. A. 20%. B. 50%. C. 70%. D. 90%.

8. In manual jewelry rolling equipment, the roll gap is adjusted using: A. Hydraulic pistons. B. Electric motors. C. Top cranks and a screw mechanism. D. Foot pedals.

9. Industrial rolling requires large investments because: A. It uses rare materials. B. Equipment is large and expensive. C. It requires manual labor. D. It produces only custom parts.

10. The starting materials for rolling come from: B. Powder metallurgy. A. Continuous casting. C. Forging. D. Extrusion.

11. Slabs typically have: A. Circular cross sections. B. Square sections up to 450 mm. C. Rectangular sections up to 350 mm thick. D. Hexagonal sections.

12. Blooms are characterized by: A. Being the smallest starting product. B. Having square or rectangular sections between 350–450 mm. C. Being used only for sheet metal. D. Being circular only.

13. Billets are mainly used to produce: A. Thick plates. B. Structural I‑profiles. D. Steel bars and wire rod. C. Railway rails.

14. Slabs are transformed by flat rolling into: A. Wire rod. B. Thick or thin sheet metal. C. Rails. D. Seamless tubes.

15. Blooms are mainly used to manufacture: B. Household appliances. A. Structural shapes and rails. C. Jewelry. D. Tinplate.

16. Wire rod is produced from: A. Slabs. B. Blooms. C. Billets. D. Thick plates.

17. In Asturias, the hot strip mill in Avilés produces: A. Rails. B. Wire rod. D. Galvanized sheet and tinplate. C. Seamless tubes.

18. Flat rolling is considered a plane strain process because: A. Width remains nearly constant. B. Length remains constant. C. Thickness increases. D. Volume is not conserved.

19. During rolling, the strip exits the roll gap at a speed that is: A. Lower than the entry speed. B. Equal to the entry speed. C. Higher than the entry speed. D. Zero.

20. The point where strip speed equals roll speed is called: A. Slip zone. B. Neutral point. C. Friction point. D. Rolling apex.

21. Before the neutral point, friction forces: B. Hinder material entry. A. Favor material entry. C. Are zero. D. Reverse direction randomly.

22. Excessive friction in rolling leads to: A. Better surface finish. B. Lower power consumption. C. Surface damage and higher energy loss. D. Increased ductility.

23. Lubricants used in rolling are typically mixtures of: B. Water and alcohol. A. Oil and water. C. Oil and sand. D. Grease and air.

24. The hydraulic mechanism in rolling mills is used to: A. Increase strip temperature. B. Rotate the rolls. D. Adjust the roll gap and apply vertical load. C. Remove oxide scale.

25. High rolling forces may cause: A. Improved accuracy. B. Roll bending and flattening. C. Increased hardness. D. Lower friction.

26. One method to reduce rolling force is to: A. Increase roll diameter. B. Increase friction. C. Reduce roll diameter. D. Increase reduction per pass.

27. Performing rolling in multiple small passes helps by: A. Increasing friction. B. Reducing required force. C. Increasing roll wear. D. Reducing product length.

28. Increasing material temperature during rolling: B. Increases flow stress. A. Reduces flow stress. C. Eliminates friction. D. Prevents deformation.

29. Applying tensile stresses during rolling: A. Increases compressive stress. B. Reduces the required rolling force. C. Causes roll separation. D. Prevents elongation.

30. Reducing friction in rolling: A. Increases power consumption. B. Reduces surface quality. D. Decreases required force. C. Prevents elongation.

31. Which part of a roll is in direct contact with the strip during rolling?. A. Journal. B. Neck. C. Body. D. Chock.

32. The neck of a roll is responsible for: A. Cooling the roll. B. Supporting the body and transmitting pressure. C. Removing oxide layers. D. Adjusting the roll gap.

33. The journal of a roll is used to: B. Apply lubrication. A. Join the roll to the coupling and transmit rotation. C. Reduce friction. D. Support the roll body.

34. Excessive roll temperature should be avoided because it: A. Increases ductility. B. Causes stress concentration. C. Accelerates wear and surface damage. D. Improves surface finish.

35. The recommended maximum roll temperature is approximately: A. 40 °C. B. 60 °C. C. 80 °C. D. 120 °C.

36. High‑pressure water jets are used in rolling mainly to: A. Increase friction. B. Cool the rolls. C. Remove scale. D. Lubricate the strip.

37. In a two‑high stand, the rolls are arranged: B. Side by side. A. One above the other. C. In a triangular pattern. D. In a cluster.

38. Roll necks are mounted on: A. Journals. B. Columns. D. Chocks. C. Backup rolls.

39. The rolling force in a stand is applied by: A. Electric motors. B. Hydraulic cylinders. C. Gearboxes. D. Cardan joints.

40. Cardan joints are used to: B. Cool the rolls. A. Transmit rotation to the roll journals. C. Remove oxide layers. D. Support the roll body.

41. A blocked roll would cause: A. Improved surface finish. D. A flat spot that damages the strip. C. Reduced rolling force. B. Increased ductility.

42. The trio (three‑high) stand allows rolling: A. Only in one direction. D. In two directions without reversing rolls. C. Only with backup rolls. B. Only thin sheets.

43. Two‑high and three‑high stands are mainly used for: A. Finishing passes. B. Cold rolling. C. Roughing stages. D. Skin pass rolling.

44. In a four‑high stand, the small‑diameter work rolls are supported by: A. Chocks. B. Backup rolls. C. Hydraulic pistons. D. Gearboxes.

45. The main purpose of backup rolls is to: B. Reduce friction. A. Prevent roll bending. C. Increase rolling speed. D. Remove oxide layers.

46. A cluster (Sendzimir) stand typically contains: A. 4 rolls. B. 6 rolls. C. 12 rolls. D. About 20 rolls.

47. Cluster stands are mainly used for: A. Hot rolling thick slabs. B. Cold rolling very thin, high‑strength sheets. C. Producing rails. D. Rolling structural profiles.

48. In a tandem mill, rolling stands are arranged: A. In parallel. B. In series. C. In a circular layout. D. Randomly.

49. In hot rolling lines, the roughing stand reduces slab thickness from about 200 mm to: A. 150 mm. B. 80 mm. C. 30 mm. D. 5 mm.

50. The final step in cold rolling lines, reducing thickness by less than 1%, is called: A. Pickling. B. Annealing. C. Scale breaking. D. Skin pass rolling.

51. Which geometrical specifications are most important in flat rolling?. A. Density and hardness. B. Thickness and flatness. C. Color and reflectivity. D. Temperature and mass.

52. Cold rolling provides better dimensional accuracy because: B. The material is softer. A. There are no thermal changes. C. The rolls are larger. D. The strip is lubricated.

53. Hot‑rolled products have poorer surface finish mainly due to: A. Excessive lubrication. B. Scale formation. C. Low rolling speed. D. High roll hardness.

54. Surface defects in rolled products may include: A. Only cracks. B. Only pores. C. Scale, oxidation, scratches, cracks, pores, inclusions. D. Only inclusions.

55. Edge waviness occurs because: A. The strip cools unevenly. B. The edges expand more than the center. C. Roll bending compresses edges more than the center. D. The rolls rotate too fast.

56. Zipper cracks appear mainly in: A. The edges of the strip. B. The central area under tension. C. The roll surface. D. The oxide layer.

57. Some cracks appear due to: A. Excessive lubrication. B. Low roll speed. D. Ductility problems at rolling temperature. C. High surface hardness.

58. Roll bending causes the strip to be: A. Thicker at the edges. B. Thicker at the center. C. Uniform in thickness. D. Completely flat.

59. Cambering a roll means: B. Cooling it rapidly. A. Grinding it so the center diameter is slightly larger. C. Increasing its rotational speed. D. Reducing its hardness.

60. Barrel‑shaped rolls in hot rolling are caused by: A. Excessive lubrication. B. Thermal gradients. C. Low rolling force. D. High roll hardness.

61. Roll flattening due to contact pressure: A. Has an easy mechanical solution. B. Reduces rolling forces. C. Must be considered in pass design. D. Eliminates residual stresses.

62. Small‑diameter rolls tend to generate: B. High tensile stresses at the surface. A. High compressive stresses at the surface. C. No residual stresses. D. Only internal stresses.

63. Large‑diameter rolls tend to generate: A. High compressive stresses at the surface. B. High tensile stresses at the surface. C. No deformation in the core. D. No friction effects.

64. It is preferred that strip surfaces experience: A. Tensile stresses. D. Compressive stresses. C. No stresses. B. Alternating stresses.

65. Shape rolling is used to produce: B. Thin sheet metal. A. Structural shapes like beams and rails. C. Wire rod. D. Seamless tubes.

66. In shape rolling, rotating the piece during rolling helps: A. Reduce friction. D. Achieve the desired geometry progressively. C. Increase rolling speed. B. Reduce temperature.

67. Thread rolling is preferred over machining because: A. It is slower but more precise. B. It wastes more material. C. It preserves grain flow and improves mechanical properties. D. It requires no tools.

68. In ring rolling, as thickness decreases: A. Volume decreases. B. Inner and outer diameters increase. C. The ring becomes shorter. D. The ring loses circularity.

69. The Mannesmann process creates a tube by: A. Melting the center of the bar. B. Cutting a hole mechanically. C. Generating a void due to tensile stresses in the transverse direction. D. Using a laser to pierce the rod.

70. Skew rolling is commonly used to produce: B. Flat plates. A. Spherical preforms for bearings. C. Structural beams. D. Seamless tubes.