Focus On Stress Corrosion Cracking

By Dr. Hira Ahluwalia, Material Selection Resources Inc.

Introduction

Unexpected or premature failure of chemical process equipment constitutes a serious hazard in terms of personnel, plant, and environmental safety. By weakening reliability, such failures also adversely affect productivity and profitability.

Modern experience in chemical plants has been that failures due to environmental cracking are among the most serious of such problems, making up about 20 to 30% of all corrosion failures. The purpose of this article is to discuss in simple terms some of the pertinent information.

General Description

Stress Corrosion Cracking (SCC) has been defined as failure by cracking under the combined action of corrosion and stress. The stress and corrosion components interact synergistically to produce cracks, which initiate on the surface exposed to the corrodent and propagate in response to the stress state.