Gripping Solutions for Tensile Testing to ASTM E8, A370, A48, and GOST 1497-1

Advances in metal properties have improved performance characteristics, bringing to market materials that are stronger, tougher, and many times more expensive to produce. 

Tensile testing of these products can present various gripping challenges. Using traditional gripping arrangements consisting of jaws or jaw faces can quickly wear out and cause slippage. 

Additionally, high production costs can mean limited material and shortened test specimens. These are common challenges faced by QC labs and often result in the need to machine shouldered test specimens. 

Shouldered or rounded test specimens are outlined in ASTM E8, A370, A48, GOST 1497-1, and other general tensile testing standards for metal products.

Challenge:

A high-volume testing lab that performs ASTM E8/A370 tensile testing using .505-inch shouldered specimens now also needs to test .357, .252, and .161-inch shouldered specimens. 

Their test system configuration includes a 300LX model with a 300kN ball-aligned tension assembly and shouldered specimen holder, and a 2-inch gauge length clip-on extensometer. 

They were having difficulty using their existing stand and were concerned about the changeover time required for the stand and extensometer, as well as the expense of adding an additional extensometer. 

Additionally, they were seeking NADCAP certification and were concerned about alignment issues with the load string.

Solution:

We recommended the new improved Split Insert Tensile Stand and (4) sets of interchangeable inserts to account for (4) different specimen sizes. 

The new grips mount directly to the existing ball tension alignment assembly and reduced test time by an average of 45 seconds per test due to the ease of use and interchangeability of the inserts. 

Alignment verification performed by Instron Professional Services fully complies with the regulatory limits outlined in ASTM E1012 and NADCAP AC7101. 

The new specimen diameter and length also introduced the need for an additional extensometer;

lixian Split Insert Tensile Grips are the preferred solution for safe, high volume production testing of shouldered or rounded machined specimens.

 Designed with the operator in mind, Split Insert Tensile Grips are easy to install, offer quick change inserts for standard specimen sizes, and facilitate efficient testing of a wide variety of metals and alloys.