Tensile testing, also known as tension testing, is a fundamental materials science and engineering test in which a sample is subjected to a controlled tension until failure. Properties that are directly measured via a tensile test are ultimate tensile strength, breaking strength, maximum elongation and reduction in area. From these measurements the following properties can also be determined: Young's modulus, Poisson's ratio, yield strength, and strain-hardening characteristics.Uniaxial tensile testing is the most commonly used for obtaining the mechanical characteristics of isotropic materials. Some materials use biaxial tensile testing. The main difference between these testing machines being how load is applied on the materials.
Various shoulder styles for tensile specimens. Keys A through C are for round specimens, whereas keys D and E are for flat specimens. Key:
A. A Threaded shoulder for use with a thread
B. A round shoulder for use with serrated grips
C. A butt end shoulder for use with a split collar
D. A flat shoulder for used with serrated grips
E. A flat shoulder with a through hole for a pinned grip
Universal tensile machine at JM Hardware®
The repeatability of a testing machine can be found by using special test specimens meticulously made to be as similar as possible.
A standard specimen is prepared in a round or a square section along the gauge length, depending on the standard used. Both ends of the specimens should have sufficient length and a surface condition such that they are firmly gripped during testing. The initial gauge length Lo is standardized (in several countries) and varies with the diameter (Do) or the cross-sectional area (Ao) of the specimen as listed
Type specimen | United States(ASTM) | Britain | Germany |
Sheet ( Lo / √Ao) | 4.5 | 5.65 | 11.3 |
Rod ( Lo / Do) | 4.0 | 5.00 | 11.0 |
The following tables gives examples of test specimen dimensions and tolerances per standard ASTM E8.
Flat test specimen
All values in inches | Plate type (1.5 in. wide) | Sheet type (0.5 in. wide) | Sub-size specimen (0.25 in. wide) |
Gauge length | 8.00±0.01 | 2.00±0.005 | 1.000±0.003 |
Width | 1.5 +0.125–0.25 | 0.500±0.010 | 0.250±0.005 |
Thickness | 0.188 ≤ T | 0.005 ≤ T ≤ 0.75 | 0.005 ≤ T ≤ 0.25 |
Fillet radius (min.) | 1 | 0.25 | 0.25 |
Overall length (min.) | 18 | 8 | 4 |
Length of reduced section (min.) | 9 | 2.25 | 1.25 |
Length of grip section (min.) | 3 | 2 | 1.25 |
Width of grip section (approx.) | 2 | 0.75 | 3⁄8 |
Round test specimen
All values in inches | Standard specimen at nominal diameter: | Small specimen at nominal diameter: | |||
0.500 | 0.350 | 0.25 | 0.160 | 0.113 | |
Gauge length | 2.00±0.005 | 1.400±0.005 | 1.000±0.005 | 0.640±0.005 | 0.450±0.005 |
Diameter tolerance | ±0.010 | ±0.007 | ±0.005 | ±0.003 | ±0.002 |
Fillet radius (min.) | 3⁄8 | 0.25 | 5⁄16 | 5⁄32 | 3⁄32 |
Length of reduced section (min.) | 2.5 | 1.75 | 1.25 | 0.75 | 5⁄8 |
Standards
Metals
ASTM E8/E8M-13: "Standard Test Methods for Tension Testing of Metallic Materials" (2013)
ISO 6892-1: "Metallic materials. Tensile testing. Method of test at ambient temperature" (2009)
ISO 6892-2: "Metallic materials. Tensile testing. Method of test at elevated temperature" (2011)
JIS Z2241 Method of tensile test for metallic materials
MPIF Test Standard 10: "Method for the Tensile Properties of Powder Metallurgy (PM) Materials" Standard Test Methods for Tension Testing of Metallic Materials" (2015)
Composites
ASTM D 3039/D 3039M: "Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials"
Flexible materials
ASTM D638 Standard Test Method for Tensile Properties of Plastics
ASTM D828 Standard test method for tensile properties of paper and paperboard using constant-rate-of-elongation apparatus
ASTM D882 Standard test method for tensile properties of thin plastic sheeting
ISO 37 rubber, vulcanized or thermoplastic—determination of tensile stress–strain properties
Purposes of tensile testing
Tensile testing might have a variety of purposes, such as:
Select a material or item for an application
Predict how a material will perform in use: normal and extreme forces.
Determine if, or verify that, the requirements of a specification, regulation, or contract are met
Decide if a new product development program is on track
Demonstrate proof of concept
Demonstrate the utility of a proposed patent
Provide standard data for other scientific, engineering, and quality assurance functions
Provide a basis for Technical communication
Provide a technical means of comparison of several options
Provide evidence in legal proceedings
Why choose JM Hardware®
At JM Hardware®, tensile testing will be performed when there is any tensile requirement on steel forgings.
The value of tensile after testing must be within the given range. And relevant tensile testing report should be provided to our customer.
In addition to tensile testing, we could also do quality control on other respects such as hardness, material, Non Destructive Testing, etc.
Contact us if you have any products with tensile requirement!