The socket weld tube fitting design is commonly used in the demanding environments of chemical and power plants. Available standard in 316 stainless steel, the socket weld fitting provides a highly reliable, sturdy and tight integral line system that remains unaffected by shock, vibration or thermal distortion. The weld used in joining a tube to a socket weld tube fitting is like any other type of "tee" weld. The root (i.e., the point of intersection of the outside of the tube and annular end area of the fitting) must be included in the weld zone. Careful welding procedures are normally followed to assure that this root area is included in the weld. If penetration is not achieved, the joint will have two built-in stress risers which may greatly reduce the strength of the weld. Upon application of an extreme load, these stress risers could result in cracks which could propagate out through the weld or tube depending upon the direction of the greatest load. The Weld-lok fitting has been designed and tested in accordance with ANSI B16.11, which covers "Forged Steel Fittings Socket Welded and Threaded." Our design parallels the Schedule 80, 3000-pound fitting pressure class, and is compatible with O.D. tube wall thickness meeting the related (3000-psi pipe class) pressure requirements. Strong, full section forgings are used for all "shape" fittings. The 316 stainless steel Weld-lok fittings fully conforms to the applicable specifications covered in: ANSI B31.1 "Power Piping", ANSI B31.7 "Nuclear power piping", Section III, "Nuclear power plant component," ASME boiler and pressure vessel code.