Standard Test Methods and Definitions for Mechanical Testing of Steel Products

 

Theory:

ASTM A370 is an umbrella spec used to cover assorted mechanical testing on steel specimens. Tests included under the specification are tensile tests, bend tests, compression tests, impact tests and hardness tests. This summary will include machine options for each type of mechanical testing procedure.

Geometry:

ASTM A370 tensile testing is very similar to ASTM E8 in that the specimens are either round or flat. Flat samples are generally tested with serrated jaw inserts while round samples use a V-insert. The size of the jaw inserts determines the allowable sample thickness within the grips.

 

Along with tensile testing, impact testing is also specified under ASTM A370 and is further specified under other impact testing procedures. Specifically, ASTM E23 which includes both Charpy and Izod test procedures for steel.  

 

Hardness testing is the final specification for mechanical testing that is described under A370. A Brinell or Rockwell testing machine can be used to test for these parameters. This is a relatively simple test and does not require extensive computer data or analysis.

Solution:

A370 tensile testing can be performed with a universal testing machine. Wedge grips must be used along with the appropriately sized load cell. Optional test equipment for this test includes pneumatic or hydraulic wedge grips and an extensometer. The extensometer can either be the Clip-on variety or the balanced version which bolts directly onto the side of the machine.

 

Impact testers are also described under ASTM A370. Universal Grip carries a full line of high quality impact testers which are manufactured in Italy by Galdabini SpA. These impact testing machines have an automatically retracting swing hammer and can be outfitted for both Charpy and Izod testing. UGC also carries a full line of complementary sample preparation equipment including sample chillers and broaching machines.

 

Hardness testers are the simplest type of testing machines that UGC supplies. These material testing systems are capable of both Brinell and Rockwell testing.

Analysis:

Analysis for tensile testing under A370 can get quite complex. Ultimate tensile strength is the most common measurement. However, further measurements can be taken using an extensometer to take elongation data. This data can be used to measure the yield point and the offset yield. Transverse strain gauges can be used to measure Poissons ratio.