Claims:WE CLAIM:
1. Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples comprising of rack and pinion for conversion of linear movement of ram of the tensile test equipment, wherein the pinion is mounted on a shaft, one end of which is secured with a fly wheel mounted with a plurality of rollers for bending of sample.

2. Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples as claimed in claim 1, which is placed on bottom plate supporting a jaw vice for holding the sample.

3. Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples as claimed in claim 1 or 2, wherein the shaft is mounted on atleast two bearings, out of which one is at another end of the shaft and another one is located at intermediate point of said shaft.

4. Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples as claimed in any of the preceding claims, wherein said rollers include a roller forming mandrel and another roller constituting guide roller located eccentrically on the fly wheel so as to produce an orbital motion with respect to the mandrel at the center of fly wheel.

5. Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples as claimed in any of the preceding claims wherein the mandrel is placed on the fly wheel with bearing to avoid friction between sample and mandrel during bending.

6. Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples as claimed in any of the preceding claims wherein the guide roller is placed with bearing at the bottom to avoid friction between the sample and guide roller, which directs the sample over the mandrel to form the bend.

7. Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples as claimed in any of the preceding claims wherein the mandrel and guide rollers are provided with sleeves of different sizes for bending of samples of different thicknesses. , Description:Wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples
FIELD OF INVENTION
[001] The present invention relates to wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples.

BACKGROUND OF INVENTION

[002] The bend test constitutes a simple and cost effective qualitative test that can be employed to evaluate both the ductility and soundness of weldments. It is often used as a quality control test for butt-welded joints, having the advantage of simplicity of both test piece and equipment. It can be carried out on the shop floor as a quality control test to ensure consistency in production. In general guided bend testing of steel is conducted with the use of a die and plunger arrangement often referred to as the plunger-type guided bend test in tensile/compression test equipment. However, the plunger-type guided bend test is not recommended for testing Aluminium weldment. The heat affected zones of welds in Aluminium alloys are significantly softer and weaker than the parent material. In case these welds are bent around a plunger, the sample bends sharply in the heat-affected zone and breaks due to HAZ softer nature. Breakage may happen due to application of instantaneous non-uniform strain and/or change in position of the weld. But in real this weldment may meet service requirement. Here, plunger bend test may be the reason for this type of errors.
[003] In order to avoid such test failures, the wrap around bend test module is required to be designed for tensile testing equipment which helps to test ductility of the weldments. This testing method forces the test specimen to bend progressively around a mandrel so that all portions of the weld zone achieve the fixed radius of curvature and the constant strain level.

[004] However, some known patents may be discussed hereinunder.

[005] US 4,656,872 relates to a WRAP-AROUND BEND TEST METHOD AND APPARATUS providing an extra attachment (modification) to the bend test equipment for wrap around bend testing. A mandrel in the shape of shoe is implemented for application of load over the testing sample. In comparison, present invention forms an extra module for tensile equipment test, which can be easily added and removed from the tensile test equipment. Roller type mandrel and guide roller is used in the module. Add on rack and pinion gear system is provided for conversion of linear moment of ram (in the tensile test equipment) into rotatory moment of a fly wheel mounted with guide roller.

[006] US 5,602,341 TEST FIXTURE FOR SPOT WELDS is directed generally to test fixtures and more particularly to a fixture for testing the strength of a resistance spot weld. However, the invention is related to testing of butt weld joint of materials not for spot welds (overlap joint).

[007] US 4,875,376 GUIDED-BEND TEST APPARATUS This patent is pertinent to die and plunger for performing tests to determine the ductility of welds. This bending mechanism is different from the mechanism used in present invention bending fixture of wrap around bending.

[008] US 7,389,699 B2 METHOD AND APPARATUS FOR TESTING SHEAR STRENGTH OF CURVED CORE MATERIAL discloses techniques for measuring properties of structural materials, wherein this equipment is designed for testing curved material (pre bended materials).

[009] Thus, none of the aforesaid currently available technologies fulfill the requirements of present invention for which it is devised.

OBJECTS OF THE INVENTION

[0010] An object of the invention is to provide wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples.

[0011] Another object of the present invention is to provide wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples which overcomes drawbacks of the prior art(s).

[0012] Still another object of the present invention is to provide wrap around test module for tensile/compressive test equipment to perform bending with controlled strain for determining ductility of welded samples which is simple and efficient.

SUMMARY OF THE INVENTION
[0013] According to the invention, a fixture is designed for testing ductility and soundness of the weld joints accurately by means of tensile test equipment. This fixture is fixable with any tensile/compression test equipment. It is having a rack which can be fixture in the jaw of tensile testing equipment (ram). Pulling/pushing of the ram of tensile testing equipment activates the loading on the sample by rack on pinion mechanism converting linear motion to rotating movement of a fly wheel mounted with mandrel, guide roller and sample to be bent.

[0014] The afore discussed fixture is placed on bottom plate supporting a jaw vice for holding the sample.

[0015] The shaft is mounted on atleast two bearings, out of which one is at another end of the shaft and another one is located at intermediate point of said shaft.

[0016] Said rollers include a roller forming mandrel and another roller constituting guide roller located eccentrically on the fly wheel so as to produce an orbital motion with respect to the mandrel at the center of fly wheel.

[0017] The mandrel is placed on the fly wheel with bearing to avoid friction between sample and mandrel during bending.
[0018] The guide roller is also placed along with bearing at the bottom to avoid friction between the sample and guide roller, which directs the sample over the mandrel to form the bend.

[0019] The mandrel and guide rollers are provided with sleeves of different sizes for bending of samples of different thickness.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0020] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and wherein:
Fig. 1 shows: Wrap around bend test module for tensile test equipment according to present invention.
Fig. 2 shows: Different positions during bending of a sample in accordance with invention.
Table 1: Table listed with different sleeve size requirements for mandrel and guide rollers to perform different thickness of samples according to the present invention.
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

[0021] The present invention imparts teaching regarding a technology pertaining to the wrap around bend test module for tensile testing equipment which helps to test ductility of the weldments. This testing method forces the test specimen to bend progressively around a mandrel so that all portions of the weld zone achieve the fixed radius of curvature and a constant strain level.

[0022] Tensile test equipment is having a ram which applies the load linearly, wherein this linear ram movement is required to be converted into circular movement to bend the sample. Conversion of the linear moment into circular is performed by rack and pinion mechanism. For this conversion, a suitable rack (1) is attached to the tensile test equipment’s ram and a pinion (2) is in place at intermediate point of shaft (3). This shaft is mounted on two bearings (4).Out of these two bearings, one is at the end of the shaft and another one is located at required length of the shaft. These bearings are placed on the bottom plate (8). This bottom plate supports the whole equipment and arrests the same in its place. Another end of the shaft is fixedly secured with a fly wheel (5). This fly wheel rotates along with the shaft’s rotation.

[0023] For the purpose of bending of the sample, this fly wheel is mounted with two rollers, in which one is placed at the center of fly wheel and another is located eccentrically on the fly wheel so as to produce an orbital motion with respect to the one at center. The roller located in the center is called as Mandrel (6).The size of this roller is the deciding factor for the radius of the bend. This mandrel is placed on the fly wheel with bearing to avoid friction between sample and mandrel during bending. The second roller positioned eccentrically on the fly wheel is called guide roller (7), which directs the sample over the mandrel to form the bend. The guide roller is also placed along with bearing at the bottom to avoid friction between sample and guide roller.

[0024] The mandrel and guide rollers’ dimensions are determined to perform the bending of a sample having particular thickness. Sleeves of different sizes are provided for mandrel and guide rollers for executing bending of particular thickness samples. Overall diameter of the mandrel and guide roller for samples of different thicknesses are given in table-1. In order to hold the sample (10) in its place, a jaw vice (9) is placed on the bottom plate.
Table 1
Specimen thickness
(mm) Dia. of Adopter for mandrel
(thick X 4) in mm Dia. of Adopter for Guide roller
(mm)
10 (max. thick) 40 20
9 36 26
8 32 32
7 28 38
6 24 44
5 20 50
4 (min. thick) 16 56

[0025] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-