The aim of this book is to be a hand book for any structure, civil, mechanical engineer and project engineer who is working in the steel structure projects. As it is the main issue in mind for any civil or mechanical engineer during construction on site for steel structure projects how to control the construction quality and specific for receiving steel materials, bolted and welded connections. Because in most college specific for civil engineering have not provide more details about welding and how to inspect the defects of the steel materials and also on the welding.The structural engineer who will provide the detailed drawings and the shop drawings for the construction, he is usually has a confusion about the welding symbol, so there will be a complete chapter to be with his hand during the drawings preparation or to read the drawings by best ways on site.The types of defects of the welding will be illustrated and how to read the radiographic photos and to determine the type of defects and what is the best method of nondestructive test that should be used.This book is tailored to be on hand book to cover the major subjects of the steel quality control onsite and the ways of inspection as the visual inspection, radiographic test, ultrasonic test, dry penetration and magnetic particle test.