IS 11790 : 1986 Code of practice for preparation of butt-welding ends for pipes, valves flanges and fittings

1 Scope

Covers the preparation of butt welding ends of pipes, valves,welding neck flanges and pipe fittings. It is also applicable toother piping components which are connected to piping system bybutt welding.

1.1 Materials for piping components for which these welding endsare primarily intended are carbon and alloy steels. They may alsobe used for nonferrous materials, upon satisfactory qualificationsof welding procedures for the particular material.

1.2 The standard includes requirement for re-entrant shapes forheavy wall ends, welding bevel profiles, inside contours, forjoints made with or without backing rings and internal andmachining dimensions with their tolerances. The preparation ofbacking rings, if any, must be specified in ordering material tothis specification.

1.3 This standard covers welding end preparation for fourgeneral types of joints but does not prescribe specific types ofwelding processes nor procedures. The four types of joints are:

a) no backing ring,

b) split or noncontinuous backing ring,

c) solid or continuous backing ring, and

d) consumable insert ring.

1.4 This standard also covers welding end preparation for gastunguston arc welding (GTAW) of the root pass.