Alloy 690 has excellent resistance to intergranular corrosion and intergranular stress corrosion cracking, mainly used in pressurized water reactor nuclear power plant steam generator heat transfer tube materials. Pressurized water reactor nuclear power plant steam generator heat transfer tube materials have gone through a development process, including 304 austenitic stainless steel, 600 alloy, 800 alloy and 690 alloy. The corrosion failure study of 600 alloy in service shows that intergranular corrosion and intergranular stress corrosion cracking are the main problems. 690 alloy, as the material for heat transfer tubes of steam generators in pressurized water reactor nuclear power plants, has not been found to be broken since it was put into use in the 1990s.