Measured Biaxial Residual Stress Maps in a Stainless Steel Weld

Abstract

This paper describes a sequence of residual stress measurements made to determine a two-dimensional map of biaxial residual stress in a stainless steel weld. A long stainless steel (316L) plate with an eight-pass groove weld (308L filler) was used. The biaxial stress measurements follow a recently developed approach, comprising a combination of contour method and slitting measurements, with a computation to determine the effects of out-of-plane stress on a thin slice. The measured longitudinal stress is highly tensile in the weld- and heat-affected zone, with a maximum around 450 MPa, and compressive stress toward the transverse edges around −250 MPa. The total transverse stress has a banded profile in the weld with highly tensile stress at the bottom of the plate (y = 0) of 400 MPa, rapidly changing to compressive stress (at y = 5 mm) of −200 MPa, then tensile stress at the weld root (y = 17 mm) and in the weld around 200 MPa, followed by compressive stress at the top of the weld at around −150 MPa. The results of the biaxial map compare well with the results of neutron diffraction measurements and output from a computational weld simulation.

Assessment of Primary Slice Release Residual Stress Mapping in a Range of Specimen Types

“…The measurement in the stainless steel DM welded plate was very similar to a different measurement reported in [13]. Both specimens used identical stainless steel parent plates, weld groove geometry, and weld bead geometry (nominally), but the specimen in [13] had a stainless steel weld metal while the current specimen had a nickel based dissimilar metal weld. Although the weld material was different between these two specimens, both had similar residual stress fields.…”

“…The primary objective of the present study is to assess the PSR mapping approach in specimens that encompass a range of key industrial alloy, geometry, and stress distribution. This work therefore complements the prior publications that laid out in detail the PSR mapping technique [9] or described its application to specific problems [13,14,15]. 3…”

“…The relevant welding parameters are: 250 A current, 10.5 V voltage, and 101.6 mm/min (4 in/min) travel speed. This specimen is similar to a stainless steel weld studied earlier [13], but here the nickel alloy weld metal is used to reflect DM welds found in nuclear electric pressurized water reactor piping.…”

“…An advantage of PSR mapping is that the in-plane stress can be mapped with relatively few measurements and additionally PSR mapping takes advantage of the high precision offered by slitting [10,11,12]. PSR mapping was first demonstrated on a quenched aluminum extrusion [9] and was subsequently applied to map biaxial residual stresses in a stainless steel welded plate [13] and a complex nuclear power plant nozzle mockup containing a dissimilar metal weld [14]. PSR mapping was recently applied to measure three orthogonal residual stress components in a quenched aluminum bar and was validated with complementary measurements by neutron diffraction [15].…”

A New Mechanical Method for Biaxial Residual Stress Mapping

“…The new biaxial mapping method has some advantages over other established residual stress measurement techniques. For example, biaxial mapping measurements in welded components have been shown to be especially useful [20,39,40]. In welds, the primary advantage derives from the use of mechanical stress release, which is largely unaffected by the microstructural issues commonly present in welds that very often complicate diffraction based measurements.…”