EFFECT OF TEMPERING TEMPERATURE ON THE RESISTANCE OF HIGH-STRENGTH STEEL 40KH BOLTS TO CORROSION CRACKING

1. Lowering of the tempering temperature of high-strength steel 40Kh bolts to t<400°C leads to a marked reduction in their longevity in a slightly aggressive atmosphere that causes the metal to absorb hydrogen during electrochemical corrosion. 2. The tendency of high-strength steel 40Kh bolts tempered in the interval of irreversible temper brittleness to failure, which is elevated in a slightly aggressive medium, is caused by additional weakening of the boundaries of former austenite grains under the action of hydrogen that is absoorbed onto them. 3. Steel 40Kh bolts with 0.37-0.43% C are not inclined to corrosion cracking in a slightly aggressive industrial atmosphere after tempering at 470°C. © 1992 Plenum Publishing Corporation.