Causes and solutions of cracks in the welds of metal hoses

Cracks in the welds of metal hoses. Process media analysis The composition of the process media synthesis water is relatively complex. The analysis shows that water accounts for about 92%, and the rest are organic substances such as aldehydes, ketones, alcohols and acids. Organic acids are mainly acetic acid, propionic acid, butyric acid and valeric acid, with the highest acetic acid content, about 1.22% to 1.32%. Organic acids and aldehydes are both corrosive, of which acetic acid is second only to formic acid (the strongest organic acid). Carbon steel is not allowed in the production and use of acetic acid. Two sampling tests were carried out on the pH of the synthetic water, which were 3.38 and 5.08, which were obviously acidic. From the above analysis, synthetic water is indeed highly corrosive. . Niu Changling, male, born in November 1967, senior engineer. Xing'erdos City, Inner Mongolia Autonomous Region. Structural analysis The protection principle of dissimilar metals determined by "Corrosion and Protection of Dissimilar Metals" should avoid direct contact between carbon steel and stainless steel hoses. When dissimilar metals are directly connected, small-area anode parts and large-area cathodic properties Parts contact. The metal hose designed in this example is directly welded to the stainless steel bellows in the corrosive environment of the site, and the entire pipe and storage tank are made of 304 stainless steel, and no insulation measures have been taken to form The adverse environment of typical small-area anode parts and large-area cathodic parts contact eventually led to rapid corrosion damage in two months. Keywords: hose PVC hose plastic hose