Posted by: wahid nawawi | April 15, 2013

API 1104 Overview

This standard covers the gas and arc welding of butt, fillet, and socket welds in carbon and low-alloy steel piping used in the compression, pumping, and transmission of crude petroleum, petroleum product, fuel gas and covers welding on distribution system. It applies to both new construction and in-service welding.

Welding process:

  1. SMAW (Shield Metal Arc Welding)
  2. GMAW (Gas Metal Arc Welding)
  3. FCAW (Flux Core Arc Welding)
  4. Plasma arc welding

API 1104 Grouping:

a. Group I materials: API 5L Gr. B, API 5L X42

b. Group II materials: API 5L X56, API 5L X60

c. Group III materials: API 5L X65, API 5L X70


Each grade (i.e. X65, X70) under group III shall require separate welding procedure qualification.

Base Material:

  • Specified minimum yield strength less than or equal to 42,000 psi (290MPa)
  • Specified minimum yield strength greater than 42,000 psi (290MPa) but less than 65,000 psi (448MPa.
  • For material with specified minimum yield strength greater than or equal to 65,000 psi (448MPa), each grade shall received a separate qualification test.

Essential variable for welder qualification:

1. A change from one welding process to another welding process or combination of process.

2. A change in the direction of welding from vertical uphill to vertical downhill or vice versa.

3. A change in filler-metal classification from group 1 or 2 or group 3, or from group 3 to group 1 or 2

4. A change from one outside diameter group another

Groups are:

  • OD  less than 2.375 in (60.3mm)
  • OD from 2.375 in (60.3mm) to 12.750 in (323.9mm)
  • OD greater than 12.750 in (323.9mm)

5. A change from one wall thickness group to another.

These groups are :

  • Wall thickness less than 0.188 in (4.8mm)
  • Wall thickness 0.188 in (4.8mm) to 0.75 in (19.1mm)
  • Wall thickness greater than 19.1mm

Continue to the next section……………….


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