b. Natural aging c. Over aging 4. Surface hardening treatments are applied to steel(1 Point) a. To increase its surface hardness and wear resistance b. To increase the hardness throughout the section c. To increase the hardenability of steel 5.Electron beam (EB) heating focuses an electron beam onto a small area to reach the austenitic temperature in(1 Point) a. Less than a second b. Few minutes c. Few hours 6.Cooling steel at a slow pace decomposes austenite to yield the phases(1 Point) a. Pearlite (alfa)+ Fe3C (cementite) b. Martensite (bct) c. Pearlite + martensite 7. The main application of nylon ( 90%) are in fibers for (1 Point) a. Carpet