X-RAY MEASUREMENT OF RESIDUAL STRESS DISTRIBUTION IN LATER HEAT TREATED TIN COATED CARBON STEELS

Abstract The development of ceramic coating to metals was stimulated by the need for high temperature, wear and corrosion resistant materials. Recently TiN is used as a ceramic coating material. In the present study, the X-ray method was successfully applied to measure the residual stress distribution in TiN coated steels. The X-ray clastic constants were determined and compared with the mechanically measured values. The results obtained are summarized as follows: (1) Mechanically elastic constants determined were As-coated: EM = 452(GPa) Quenched and tempered: EM = 565(GPa) (2) The X-ray elastic constants by the use of cobalt target determined were As-coated: (1 + ν)/E = 2. 16 × 10−3 (GPa−1) ν/E = 2.55 × 10−4 (GPa−11) Quenched and tempered: (1 + ν)/E = 1.81 × 10−3 (GPa−1) ν/E = 4.42 × 10−4 (GPa−1 ) for TiN(420) phase. As-coated EX-ray was 524 (GPa) which was higher than the mechanically determined value of 452 (GPa), respectively. And Quenched and tempered EX-ray was 730 (GPa) which was lower than the mechanically determined value of 565 (GPa), respectively. (3) The X-ray elastic constants by the use of chrome target determined were As-coated: (1 + ν)/E = 1.91 × 10−3 (GPa−1 ) ν/E = 1.76 × 10−4(GPa−1 ) for TiN(222) phase. As-coated test piece EX-ray was 577(GPa) which was higher than the mechanically determined value of 452 (GPa), respectively. (4) The residual stress distribution determined by the X-ray method indicated high compressive stress. It is above from −2.5(GPa) to −3.5 (GPa) in the TiN layer.