A roll forming type square steel pipe (BCR) has high sensitivity than a press forming type square steel pipe (BCP) to Zinc Induced Cracking (ZIC) . ZIC is observed at the corner showing the initiation site at inner side. Some factors are estimated to control the occurrence of ZIC, plastic strain, residual stress at inner side, and free C and⁄or free N of steel. At heating process to galvanizing temperature, the corner of pipe becomes brittle due to the strain aging. Micro crack is easily initiated under the condition if yield stress exists. BCR has high residual stress equal to yield stress that can initiate micro crack. BCP has low residual stress that is not sufficient to initiate micro crack.
A piping plan depends on inspection history or inspection data in order to extract propensity of damage mechanism. The inspection data are ①Periodic maintenance inspection record (SDI) , ②On-stream inspection data (OSI) , ③Unplanned stop or extraordinary inspection records and ④corrosion-loop database visualized by evaluating corrosion rate as a corrosion system. Each of injury site of corrosion thinning with an organic acid as a specific injury mechanism, operating temperature conditions as a condition for extracting parts, fluid corrosion factor, structure factor, and material is quantified qualitatively or semi-qualitatively. It states that priority order by data visualization of damage propensity (Bayesian theorem) is required.
On January 9, 2014, a chemical leaked from an aboveground storage tank at the Freedom Industries'facility in Charleston, West Virginia, USA. The leaking chemical was originally reported as Crude MCHM, but 13 days later it was determined to be a mixture of Crude MCHM and PPH stripped, called Shurflot944. The chemical escaped through two holes on the tank bottom, and entered the adjacent Elk River. The chemical flowed downstream to the intake of the West Virginia American Water's water treatment plant. The plant was unable to remove the chemical, and the drinking water was contaminated. The Do NOT USE Order was issued for approximately 300, 000 residents who lived around Charleston. The U. S. Chemical Safety and Hazard Investigation Board (CSB) released the final report on the cause of this incident on September 28, 2016. This paper describes the incident based on the CSB report.