Mechanical behaviour

Last updated on Mon, 11/12/2012 - 12:12

Robustness and mechanical strength

Pipe system components must withstand hazards before they reach the job site such as accidental impact before and during installation, during storage, handling and transit.

In service, outdoor exposed pipes may be damaged by accidental impacts or vandalism.

To avoid breakages which can be expensive or minor stress cracks, which can have serious consequences in operation, the choice of material should be carefully considered.

Impact strength and crush resistance

Cast iron is well-known for its robustness. The quality of PAM products is ensured by careful control of both metal composition and manufacturing process.
The spinning of pipes in the De Lavaud process, followed by heat treatment, gives these products outstanding mechanical properties.

Key mechanical characteristics required by the standard EN 877 are controlled by three tests, carried out on pipes when coming out of the heat treatment furnace. They assess:

  • tensile strength,
  • ring crush resistance
  • and hardness.

In addition, operators have opted to maintain a further test which gives a good indication of the quality of heat treatment: the guillotine impact test.

The pipes SAINT GOBAIN PAM process Others EN 877 requirements
Tensile Strength on samples in MPa (average value) 300 270 200 mini
Ring Crush Strength in MPa (average value, DN  100 pipes) 450 360 350 mini
Brinell Surface Hardness in HB degree (average value) 220 245 260 maximum

These results indicate greater resistance to impacts and crushing, easier machining and cutting. This also means the products are easier to install on job sites.