Tension Test Specimen for Gray iron and Ductile Iron Castings
Tensile strength is the most important
physical property for inspecting
gray iron and ductile iron
castings. Tension test specimen is also called as tensile bar, or
tensile test bar.
Although there are some standards that stipulating the dimensions of
tension test specimen, however, it is difficult for casting buyers
to send the requirements for test bars to their suppliers.
Sometimes, the buyers need their suppliers to provide some test
bars, and entrust the third party to perform the test, so they need
to know what kinds of test bars commonly used.
The followings are the drawings for gray iron and ductile iron
castings. Because of the difference of materials, the test specimen
of grey cast iron is different with that of ductile cast iron.
Briefly, the gray iron tensile bar is larger than ductile iron
tensile bar. Therefore, in order to make the test machine to hold
the test bar more firm, a simple screw thread, normally 1mm tooth
space, will be necessary.
The test specimen of gray iron is diameter 20mm +/-0.1, the ductile
iron bar is diameter 14mm +/-0.1. As for the other dimensions,
please see the following drawings.
Ductile Iron Tensile Test Bar
Gray Iron Tensile Test Bar
The above tension test specimens are
made during production with the castings, but not cut from the
castings. If you want to cut a specimen directly from the castings,
then you may need smaller tensile bars, such as diameters 5mm, 7mm,