EN ISO 5173 Destructive Tests on Welds in Metallic Materials - Bend Tests

The standard "EN ISO 5173 Destructive testing of welds in metallic materials - Bend tests", which has its basis in a European standard and was subsequently published by the International Organization for Standardization (ISO), describes the method of performing transverse root, face and side bend tests on test specimens taken from butt welds, clad butt welds (subdivided into welds in clad sheets and clad welds) and clad without butt welds, in order to reveal defects at or near the surface of the test specimen under tension during the bend test or to evaluate ductility.

This standard also specifies the dimensions of the test specimen. It also specifies methods to be used in place of transverse bend tests with a die for welded joints when the base materials, heat-affected zones, or weld metal have significant differences in physical and mechanical properties compared to bending. This standard applies to metallic materials in all product forms with welded joints made by any welding process.

For the purposes of this standard, the following terms and definitions apply:

• The cross face bending test specimen for one end welding refers to the cross face welding specimen in which the face is tensioned.
• The transverse root bending test specimen for one end welding refers to the transverse end welding specimen in which the root is tensioned.
• Transverse side bend test specimen for one end welding refers to the weld specimen in which the surface under tension is the weld section.
• The longitudinal face bending test specimen for one end welding refers to the specimen whose direction is parallel to the end welding direction and the face is in tension.
• The longitudinal root bending test specimen for one end welding refers to the weld specimen whose direction is parallel to the end welding direction and the root is in tension.
• The face bend test specimen for non-butt-welded cladding refers to a specimen in which the cladding is in tension. It can be applied to both transverse and longitudinal specimens.
• For cladding without butt-welding, the side bend test specimen refers to a specimen in which the cladding cross-section is under tension. It can be applied to both transverse and longitudinal specimens.
• Face bend test specimen for butt weld cladding refers to a butt welded specimen in which the cladding is in tension.
• Side bend test specimen for butt welded cladding refers to the butt welded specimen in which the cross-section of the cladding is in tension.

In principle, when performing the test, a transverse or longitudinal test specimen is taken from a welded joint and subjected to plastic deformation by bending it, without reversing the bending direction, such that one of the surfaces or sections of the welded joint is under tension. The temperature at which the tests are performed should be recorded. The test speed should be constant and, when known, should be recorded. The test should be performed in accordance with one of the methods described in this standard.

The test methods described in EN ISO 5173 are used to evaluate the ductility and strength of welds, specifically the ability of the welded material to undergo plastic deformation without cracking. The main bend test methods are:

• Face bend test: The outer surface (face) of the weld is placed in tension. This test is performed to check for cracks, lack of fusion, incomplete penetration, or other weld defects and to ensure the weld metal and heat-affected zone can withstand plastic deformation.
• Root bend test: The root (opposite side) of the weld is placed in tension. This test is performed to detect root defects such as incomplete penetration, incomplete fusion, porosity, cracks at or near the root of the weld, and to ensure that the root area can undergo plastic deformation without failure.
• Side bend test: A cross-section of the weld is tested with the side in tension. This test is performed to identify internal defects that cannot be detected by face or root bend tests alone and to ensure that the entire weld area has sufficient ductility and strength. It is typically used when the material thickness is too great for face or root bend tests.
• Longitudinal bend test: A specimen is bent along the axis of the weld (less common). This test is performed to evaluate the overall ductility of the weld and surrounding areas along the weld direction and to identify defects such as longitudinal cracking, lack of fusion, inclusions, and weld-aligned porosity.

These test methods are used in a variety of situations to evaluate the mechanical integrity and strength of welded joints in metallic materials.

Test specimens should be prepared so that the preparation process does not affect the base material or weld metal. The size and preparation of the specimens depend on the material thickness and the type of bend test. Specimens are typically rectangular and machined from a welded joint.

When performing the test, the sample is placed on two supports and bent over a die (mandrel) of a specific diameter. Depending on the method, bending can be performed using a guided bend testing machine or rollers. The bending angle and die diameter are selected based on the material type and thickness.

After bending, the test specimen is examined for surface cracks or other discontinuities. Acceptance criteria are based on the maximum allowable crack sizes or the presence of any obvious defects. Cracks caused by edge effects or pre-existing defects (not related to welding) may be ignored if clearly identified.

In short, the purpose of this standard is to ensure that welded joints have adequate ductility and are free from significant internal or surface defects. It is commonly used in weld qualification testing and quality control of welded products.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the EN ISO 5173 "Destructive testing on welds in metallic materials - Bend tests" standard.