Cause of Cracking on Inner Cavity in Rectangular Pulsating Vacuum Sterilizer

The inner cavity of rectangular pulsating vacuum sterilizer in a hospital cracked. The causes of cracking on inner cavity were analyzed by means of macro analysis, metallographic examination and spectrum analysis, combined with working medium. The results show that the welding residual stress existed in the discontinuous welding joint between the inner cavity and the reinforcing rib, and the local stress concentration phenomenon existed near the bending part of inner cavity. The working medium of the sterilizer contained chloride ion, and chloride ions aqueous solution was the sensitive medium for stress corrosion cracking of 300 series stainless steel. Under the combined effect of welding residual stress and chloride ion medium, the stress corrosion cracking of the inner cavity of sterilizer started from the welding beginning near the bending of inner cavity.