From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Directions for the study and testing of material properties, detailing specimen dimensions and procedures for plastic yield and strength tests.
| Identifier | ExFiles\Box 24\2\ Scan212 | |
| Date | 21th February 1922 guessed | |
| 570 DIRECTIONS FOR THE STUDY OF width of the specimen may be reduced to a minimum of 12 mm, the other dimensions remaining as in Fig. 8. blow may be made by altering the velocity within the limits given above. Larger alterations have to be effected by changing the mass of the pendulum. FIG. 9.—Specimen for Plastic Yield with Temperature Test and Cross-breaking Strength Test, machined from Sheet or Rod, or Moulded. As certain materials may have different values for toughness, depending on the direction of the blow with reference to the surface of the sheet, whenever possible impact tests shall be carried out with the blow delivered in directions parallel to, and at right angles to, respectively, the surface of the sheet. The velocity of the pendulum at impact shall be between 180 and 220 cm per second. The minimum energy required to break 7. Plastic Yield with Temperature (Rigidness). The plastic yield with temperature of material in moulded, sheet, or rod form, shall be tested on a specimen of the shape and dimensions shown in Fig. 9. When it is impracticable to obtain sheet 15 mm thick the width may be reduced to 12 mm, the other dimensions remaining as in Fig. 9. Fig. 10 shows the method of applying the test. The FIG. 10.—Arrangement of Specimen in Fig. 9 set up for Plastic Yield with Temperature Test and Cross-breaking Strength Test. the specimen shall be ascertained, and shall be expressed in kg cm per sq. cm of the broken surface. The energy remaining in the pendulum after breaking the specimen shall not exceed 25 per cent of the total blow in any test, and shall be less when practicable. NOTE.—Whilst the specimen should be as nearly as possible of rectangular section, the bedding of the pendulum is improved by giving a slight curvature to clearance between the sides of the specimen and the stirrup shall not exceed 0.5 mm. The specimen shall be fixed in the clamps without loading and a measurement made of the height of the unsupported end above the datum point. The specimen shall be heated for two hours at a temperature 5 deg. C. above grade temperature, and a load then applied. For a specimen 15 mm wide the load shall FIG. 11.—Alternative Smaller Specimen for Plastic Yield with Temperature Test and Cross-breaking Strength Test, machined from Sheet or Rod. the vertical edge of the supports, such that the point of contact with the specimen will be on the centre line of the latter. Small adjustments of the energy of be 450 grammes, and for other widths 30 grammes per mm. The specimen shall be maintained thus for 20 hours, at the end of which period, and whilst still | ||