Tensile Test

Tensile Test

Tensile Test - It is one of the most widely used mechanical tests.
A tensile test helps determining
(a) Tensile properties such as tensile strength, yield point or yield strength and modulus of elasticity.
(b) Ductility of a weld. Two standard measurements of ductility are the percent elongation and the percent reduction of area.

Preparation of Test Specimen
1. Transverse Tensile Test
Using Radius Reduced Specimen
Using Reduced Specimen

2. All weld Metal Tensile Test
A transverse Tensile Test specimen is cut from a welded butt joint (at right angle to the weld direction and is used to determine its transverse tensile strength. Reduced transverse test specimens are not intended to give the tensile strength of the weld metal, but Radius reduced specimens do occasionally.

Width	Gauge Length*	Minimum Parallel Length	Minimum Radius at Shoulder	Total Length
b	Lo	Lp	r	L
Plate thickness but not less than 25 mm	50	60	25	200
	100	110	25	300
	200	225	25	375

In an all weld metal tensile test, the specimen is prepared from all weld metal. This type of specimen is prepared by machining a groove in a plate of steel and then completely filling the groove with deposited weld metal. The surrounding steel is then machined away leaving a specimen of weld metal.
The purpose of such a test is to test
(i) Electrodes for their suitability for the job concerned,
(ii) The quality of deposited metal in welded joint.

Cross-sectional Area,Ao,mm²	Diameter do	Gauge Length, Lo	Minimum Parallel Length, Lc	Minimum Radius, R
400	22.56	113	124	23.5
200	15.96	80	88	15.0
100	11.28	56	62	10.0
25	5.64	28	31	5.0

Test Procedure
Tensile test is carried out by gripping the end E, E of the specimen in a tensile testing machine and applying and increasing pull on to the specimen till it fractures.

During, the test, the tensile load as well as the elongation of a previously marked gauge length in the specimen is measured with the help of load dial of the machine and extensometer respectively. These readings help plotting stress strain curve.

After fracture, the two pieces of the broken specimen are placed as if fixed together and the distance Lf between two gauge marks and the area Af at the place of fracture are noted.

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