engleski

Threshold stress of heat treated low alloy Cr-Mo steel

In this work the results of low alloyed Cr-Mo steel microalloyed with niobium are presented. After quenching at 870oC (30 min.) and air tempering at 720oC (60 min.) of tubings according to API 5CT Standard corresponding to API grade C- 95 have been obtained. Their corrosion resistance determined by constant load method is high and has threshold stress value of 75% yield strength (541 MPa). Specimens whic came through 720 hour test in NACE solution and which were subsequently tested by fractographic have shown a high resistance to SSCC because they have not failured in spite of absorption of a remarkable quantity of hydrogen whic is proved by absoutly brittle transgranular cleavage fracture.

low alloyed steel, API degree, stress corrosion, heat treatment, threshold stress

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