Copyright Goodheart-Willcox Co., Inc. 276 Gas Tungsten Arc Welding Handbook parts are sprayed with a salt mixture and allowed to corrode, simulating years of exposure to the weather. Such tests are usually required by the specifi cation used by the fabricator. Weld test parameters made on the qualifi cation test weldments must be duplicated on the production part without deviation to maintain the proper corrosion resistance. Ferrite Test A ferrite test on completed stainless steel welds determines the amount of magnetic ferrite in an austenitic (nonmagnetic) weld. Insuffi cient ferrite in a weld made under high restraint is prone to cracking at red heat. Limits of ferrite will depend on the use of the fi nal weldment. These amounts are usually specifi ed in the fabrication specifi cation. Weld test parameters and fi ller metals used on qualifi cation test weldments must be duplicated on the production part without deviation to maintain the proper ferrite content. Weld Repair If a weldment fails inspection, the welding inspector will review it in order to determine the extent of damage that may be caused by repairing the weld and whether the weldment can fulfi ll its func- tion if the defect is allowed to remain in place. If the function of the weldment is affected by the defect, the weldment must be discarded and replaced. In some cases, the defect may not affect the function- ality of the weldment, in which case it can be left. These determinations are made on a case-by-case basis. If a part requires rework, a thorough welding procedure should be established to minimize the effect of the repair on the remaining portion of the weld. This procedure must consider the procedure used to create the original weld. It must also consider the following: • Condition of the base metal and weld • Type of fi ller metal to be used in the repair • Welding sequence • Any in-process inspection required during the repair • Tooling required for the repair • The fi nal weld’s mechanical properties Incomplete consideration of any of these factors may result in further rejection of the weld repair and possible failure of the weld when placed into service. Dimensional Repairs Dimensional repairs are repairs that are required because the weld is too small for the material and joint type. These repairs involve the addition of material to increase weld size and are usually necessary due to the insuffi cient quantity of fi ller metal being added during the welding operation. Conditions that require dimensional repairs are as follows: Figure 18-21. Round-type tensile bars are shown in the foreground of this image. (Photo courtesy of Tinius Olsen) Figure 18-22. A flat tensile test bar is being tested. (Photo courtesy of Tinius Olsen)