AWS C3.2M/C3.2

The purpose of this standard is to describe the test method used toobtain reliable data on thestrength of metal-to-metal, metal-to-nonmetal, andnonmetal-to-nonmetal brazed joints. Testspecimens should be prepared using consistent and proper fabricationand brazing practices.Interpretation of the test results is the responsibility of the user.

It should be recognized that if the production practices for thebrazed product do not follow thetest specimen brazing practice, the joint strengths of the testspecimen might not be the same asthe product’s joint strengths.

It is important that the user of this test maintain sufficientdocumentation of the materials,brazing parameters, and test conditions. This documentation will berequired when comparing theresults to the joint strengths obtained by others using this standardmethod. General use of thisstandard method may permit a compilation of brazed joint strengths andbrazing design criteria atsome future time.

The mechanical performance of a braze joint is necessarily anintegration of the filler metal, thebase metal, the geometry of the brazement, and the brazing procedure.Moreover, the properties ofthe base metal may be sensitive to the process parameters and jointoverlap. As the overlap isincreased, the failure location shifts from failure in the braze jointto failure in the basemetal. Joints made with an overlap greater than this transition valuewill behave as being strongerthan the materials being joined together. Material thicknesses (T)other than 3.0 mm (0.125 in.)may be used for test specimens. Overlaps should be adjustedaccordingly.

When testing for long-term shear data such as stress rupture and creepproperties, the double-lapshear specimen is required to achieve uniform test conditions. Shearstrength versus overlapproperties for the double-lap specimen show results similar to thoseobtained for the single-lapspecimen.

The butt tensile specimen provides the tensile strength of the basemetal-filler metal combinationswhen tested in tension. This specimen is not suitable for all fillermetals such as those thatproduce butt tensile strengths far below the properties of the basemetal. Filler metal-base-metalcombinations of higher strength are often diffusion brazed to developmechanical properties equalto those of the base metal. These tests provide excellent data fordesign purposes. The butt brazedtensile specimen can also be used to obtain stress rupture and creepdesign data. Moreover, impactand fatigue specimens can be cut from the butt brazed specimens.

The four-point bend specimen is specifically designed to obtain thebutt tensile strength data of abrazed specimen that has very limited or no ductility. Typical ofthese materials are ceramics,graphite, cermets, and other similar materials.

Units of Measure and Rounding-Off Procedure. This specification makesuse of both the InternationalSystem of Units (SI) and inch-pound units. The standard sizes anddimensions in the two systems arenot identical. For this reason, a conversion from a standard size ordimension in one system willnot always coincide with a standard size or dimension in the other.However, if appropriatetolerances are applied in each case, suitable conversions encompassingthe standard sizes of bothsystems of units can be made.

Edition:

01

Published:

01/01/2001

Number of Pages:

31

File Size:

1 file , 640 KB