[en] Single U-bends of 18Cr10Ni, 20Cr25Ni, 22Cr34Ni and 17Cr72Ni alloys with different contents of the impurities As, Sb and Bi have been exposed to a 100 ppm Cl^- and 0.2 ppm O₂ sodium shloride solution at 320 deg C in a refreshed autoclave. The 18Cr10Ni U-bends have been exposed for 1000 h and the others for 5000 h. The primary objective of the test was to examine the influence of the impurity additions upon the stress corrosion cracking resistance. Transgranular or mixed inter- and transgranular stress corrosion cracking has been found in 13 out of 35 U-bends of the 18Cr10Ni alloy, 4 out of 35 U-bends of the 20Cr25Ni alloy and 3 out of 30 U-bends of the 22Cr34Ni alloy. Of the impurities As was found to have a deleterious influence on the stress corrosion cracking resistance, but no obvious influence was found for Sb and Bi. While no transgranular cracking was found in the U-bends of the 17Cr72Ni alloy, this nickel-base alloy showed poor pitting resistance and extensive intergranular attack in crevice regions