Steel – Cutting

Steel and weld metal may be thermally cut provided a smooth and regular surface, free from cracks and notches is obtained. All thermally cut surfaces shall be produced using a mechanically guided torch unless otherwise approved by the DCES. Thermal cut surfaces produced by a manually guided torch, when allowed, shall be smoothed by machining or grinding. In all thermal cutting, the cutting flame shall be adjusted and manipulated to avoid cutting beyond (inside) the prescribed lines. The roughness of thermal cut surfaces shall not exceed the American National Standards Institute surface roughness value of 1000 micro inches for material up to 4 inches thick and 2000 micro inches for material 4 inches to 8 inches thick, except, at the dead ends of members where there is no calculated stress, the roughness shall not exceed 2000 micro inches. Roughness exceeding these values and occasional notches or gouges no more than ¼ inch deep on otherwise satisfactory surfaces shall be removed by machining or grinding. Cut surfaces and edges shall be free of slag. Correction of discontinuities shall be faired to the oxygen cut surfaces with a slope not exceeding 1 in 10. Occasional notches or gouges that exceed ¼ inch shall be repaired by welding. The repair of notches or gouges over 7 /16 inch deep shall be referred to the DCES before repair. Welding repairs shall be made by suitably preparing the discontinuity, welding with an approved process after preheating .Minimum Preheat and Interpass Temperature and grinding is required to complete weld with smooth and flush with the adjacent surface to produce a workmanlike finish. All welded repairs to main material subject to tensile stress shall be tested by ultrasonic or radiographic inspection as determined by the DCES. Reentrant corners shall be filleted to a radius of not less than ¾ inch. On main material, carrying primary stress, a 2 inch [50 mm] minimum radius shall be provided wherever possible. The radius and its contiguous cuts shall meet without offset or cutting past the point of tangency. The surface to be welded must be adequately smooth, uniform, and free from fins, tears, cracks and other discontinuities which would adversely affect the quality or strength of the weld. Surfaces to be welded and surfaces adjacent to a weld must also be free of loose or thick scale, slag, rust, moisture, grease and other foreign material that will prevent proper welding or produce objectionable fumes. Mill scale capable of vigorous wire brushing, a thin rust inhibitive coating, or a compound may remain except that all mill scale shall be removed from the surfaces on which flange-to- web welds are to be made by any of the approved welding processes.