We manufactures swage nipples and bull plugs in accordance with A234, A420, A403 and MSS-SP95, from A106B, A333-6 seamless pipe and A1000 series, low to medium carbon, fine grain, cold drawn bar stock, and heat-treated to these specifications. The chemical and physical properties of the raw material fall within the ranges. Due to the wide variation in service conditions, temperature, vibrations, etc.,. SKEI can make no recommendations as to allowable working pressures of swage nipples and bull plugs. There is a number of working pressure formulas from which the end user may choose to determine the required wall thickness of the piping system based on the applicable code of construction. It is our responsibility only to furnish a fitting with end dimensions equal to those of the pipe size and schedule ordered.