In recent years petroleum refinery and chemical plant become increasingly larger and those practical working conditions (temperature, pressure, corrosions, environments, etc.) also become very severe. Accordingly, the high grade qualities and securities (free from any weld defects) of metals were required for almost of welded joints. In this paper, both the manufacturing procedure and the metallurgical characteristics of roll clad steel plate and several significant problems, such as design for welding, post-weld heat treatment, influence to the quality control and reliability of pressure vessels, have been described. Above mentioned matters of fact are described on the basis of my experience and many years daily works. It would be appreciated if you would like to have any advantages from this study.