Tensile Testing

— Determination of the tensile strength and failure mode of test pieces from a butt-fused joint.

Pipe weld samples are machined from a butt-fused pipe joints to give a weld sample that is subjected to a tensile stress at a constant speed of 5mm/minute in the PIPETEST AUSTRALIA NATA certified laboratory.

When loading the test samples in one of our 100kN mechanical testing machines with state of the art software which allows for the choreographing of all the test information in an easy to view format, providing graphs and calculations automatically, the stress in the tensile test samples is concentrated through the weld joint area with the mode of separation being ductile or brittle in the vicinity of the joint.

The failure mode and tensile strength are used as criteria for the evaluation of the butt-fused joint. Each test sample required, a section of the weld area being cut and machined out along the longitudinal direction of the pipe weld, across the joint. The weld samples are machined into a dumb bell shape samples in our new computer controlled CNC router machine that profiles the samples to meet any specific shape required for a standard. This new process has led to fast turnaround times for results for our clients.

     •Pipes with wall thickness under 25 mm are machines to a type A test sample.

     •Pipes with wall thickness over 25 mm are machined to a type B test sample

When sending test welds they need to be cut 250 mm either side of the weld bead center, and if a parent pipe tensile test sample is require on your project, one side of the weld needs to be cut at 300 mm from the center on the weld bead.

The test welds need to be clearly marked, with a project number, welder personnel identification number and name, weld joint identification number and welding machine ID and date welded.

The number of test pieces depends on the nominal outside diameter of the pipe, as given in the below table.
Nominal outside diameter (dn) mm Pipe Number Test sample.
  25 to 110 mm 2
  110mm to 180 mm 4
  180mm to 315 mm 6
  315mm above 7

Tensile test sample results are required to pass in a ductile mode after separation as this shows a quality weld, if the result is a Brittle or mixed mode after separation, there is a problem with the welding process.Tensile Testing is an essential means of ascertaining the integrity of butt fusion welds produced and helps identify poor quality production welds at the earliest stage, before it has the potential to become a costly error.

PIPETEST AUSTRALIA can do all your testing leaving the client with confidence in the work being carried out in a quality standard. We provide a service for making sure your next project runs well by verifying welding machines, qualifying the welding personnel and verifying welding parameters and procedure at the start of the project and during installations or production.