Consider the following statements pertaining to the open die forging of a cylindrical specimen between two flat dies: 1. Lubricated specimens show more surface movement than unlubricated ones. 2. Lubricated specimens show less surface movement than unlubricated ones. 3. Lubricated specimens show more barrelling than unlubricated ones. 4. Lubricated specimens show less barrelling than unlubricated ones. Which of these statements are correct? Correct Answer 1 and 4 Explanation: During the hot forging process, if the metal is not properly heated & completely soaked in a furnace, there will be a temperature difference between the outer surface & inner core. When the force is applied during forging stroke, the outer surface will elongate/compress more as compared to the inner core & the material may not remain truly cylindrical, showing some budge. This phenomenon of production of budge is known as the barrelling effect. The barrelling may happen due to excessive friction between the die & the material to be forged. The use of lubricant results in a reduction in the friction between the die surface and specimen so, the lubricated specimens show more surface movement than unlubricated ones, So, the barrelling is minimized by lubricating the specimen. [ src="//storage.googleapis.com/tb-img/production/21/06/F1_Yerra_Ravi_25.06.21_D1.png" style="width: 522px; height: 205px;">