BS EN ISO 7539-10:2020 pdf free.Corrosion of metals and alloys -Stress corrosion testing.Reverse U-bend method.
BS EN ISO 7539-10 The RUB test is a particularly severe test for assessing susceptibility to stress corrosion cracking.The test is intended primarily for application to metals with high corrosion resistance, such as Ni-based alloys, with the advantage, compared to methods such as the conventional U-bend test, of having significantly less stress relaxation. It is used primarily as a screening test for tubing, piping,plate, bar and other products including welded materials. It may also be used as an acceptance test for performance in service subject to agreement between the parties.The principle of the test is to introduce very severe stresses in a high corrosion resistance metal, with minimum relaxation, in order to enhance the likelihood of inducing stress corrosion cracking.
The test involves exposing a piece of metal of a semi-circular section bent back on itself (i.e. reversed bent) into a U-shape to the corroding medium and holding it in a manner that ensures that there are initial tensile stresses in excess of the yield strength over a large proportion of the inner surface. The
test is accelerated by the presence of complex bi-axial stresses that may or may not exist in service. In the act of forming specimens, varying amounts of cold work may be introduced, and this deformation.When testing welds, consideration shall be given to the orientation of the weld relative to the longitudinal axis of the specimen and this shall be noted. Tests may be conducted on the weld metal itself or on sections containing the weld metal and heat-affected zone. The bolting material should have a similar or lower coefficient of thermal expansion to that of the specimen. Washers with a curved surface should be used to avoid non-uniform loading on the specimen during the screwing of the bolt. The washers help to keep the same contact point on the bolt-holes of a specimen. In addition, the use of double nuts to reduce the likelihood of loosening of the bolts is recommended.BS EN ISO 7539-10 pdf downlaod.