Jan Storesund - Academia.edu (original) (raw)

Papers by Jan Storesund

Materials at High Temperatures, Oct 20, 2022

Corrosion Engineering Science and Technology, Jun 1, 2009

Welding Research Abroad, 1993

International Journal of Pressure Vessels and Piping, 2001

ABSTRACT In the present study, creep crack growth (CCG) in a circumferentially welded low alloyed... more ABSTRACT In the present study, creep crack growth (CCG) in a circumferentially welded low alloyed pipe is numerically investigated for a number of different combinations of weldment constituent material properties. A creep ductility based damage model describes the accumulation of creep damage ahead of the crack tip where a constraint parameter and the creep strain rate perpendicular to the crack plane are used as characterising parameters. It is assumed that a fully circumferential creep crack, located in the heat affected zone with a depth of one quarter of the pipe thickness, is growing at a constant rate from the outer surface towards the inside. The numerical results reveal that not only the properties of the zone containing the crack, but also the deformation properties of the surrounding material influence the CCG behaviour. This influence can be noted on the characterising parameters used for the CCG rate predictions as well as on the CCG rate itself. The mismatch influence on corresponding C∗ values is, however, marginal. This indicates that determination of the CCG rate in weldments, based on the C∗ value only, may result in uncertain estimates.The numerically investigated cases are also assessed by use of the R5 procedures for the sake of comparison. Considering the stress re-distribution, due to the mismatch effect, the CCG rate is determined for the different weldment configurations. The comparison shows that the assumption of plane strain or plane stress conditions in the R5 analysis is essential for the agreement of the results between R5 and the two-parameter approach. Assuming plane stress conditions at the crack tip results in a relatively good agreement for the axial stress dominated cases investigated. However, for the hoop stress dominated cases, the R5 procedures predict higher CCG rates by an order of magnitude.

International Journal of Pressure Vessels and Piping, 1996

In order to reduce production costs, it is of great interest to use longitudinal seam welds when ... more In order to reduce production costs, it is of great interest to use longitudinal seam welds when manufacturing large diameter pipes. The cost reduction can be as high as 30%. However, severe inservice accidents for this type of pipes working in the creep regime have occurred mainly due to mismatch in weldment creep properties.In many cases, creep tests of cross-weld

International Journal of Pressure Vessels and Piping, 1995

Cross weld creep testing is an experimentally straightforward method to estimate the creep streng... more Cross weld creep testing is an experimentally straightforward method to estimate the creep strength in a welded joint. Interpretation of the results can be complicated by a complex of interacting creep properties in the weldment and differences in the stress distribution between uniaxial load cross weld creep test specimens and welded components.Stress distributions in cross weld specimens are in the

A couple of unexpected and serious creep failures in live steam pipe components occurred in Swede... more A couple of unexpected and serious creep failures in live steam pipe components occurred in Sweden some years ago. The service temperature was 450°C which is 30°C below the limit temperature for creep design for the used steel grade in the cases of point, 13 CrMo 4 4 (1Cr0,5Mo). This steel is also the most commonly used material in Sweden for steam lines operating at 420 – 480°C. Consequently, a number of steam pipe systems at other plants with similar service data were inspected with respect to creep for the first time. Creep cracks and creep cavitations were found in several of them. Damages were foremost observed in welds in T-joints. Some of these T-joints were retired and retained for metallographic investigations. Among those that had operated at 450°C significant creep cavitations were observed in vicinity to cracks but in general the spreading of cavities was smaller than typically observed in the creep range. Furthermore, parametric stress and creep crack propagation analys...

Materials at High Temperatures, 1994

The effect of postweld heat treatment on creep properties of manual metal arc welded joints of th... more The effect of postweld heat treatment on creep properties of manual metal arc welded joints of thick walled pipe of 1Cr-0.5Mo steel has been studied at 550 o C. The creep properties were determined for parent and weld metal in addition to those for crossweld specimens with controlled microstructures such as refined and coarse grained heat affected zones. Metallographical investigation of cavitation on ruptured samples was also performed. A reduction in creep life and an increase in ductibility were observed, in comparison with the as welded condition. A beneficial influence of grain refinement in the heat affected zone was observed giving a reduced number of creep cavities

Steel Research, 1995

The influence of post weld heat treatment on hardness and impact toughness properties of weldment... more The influence of post weld heat treatment on hardness and impact toughness properties of weldments of 1CrO.5Mo and 2.25Cr1Mo steels has been investigated. Post weld heat treatment significantly reduced the hardness and the impact transition temperature and increased the upper shelf energy. The decrease in hardness was essentially larger for 2.25Cr1 Mo than for the other steel, probably due to the presence of martensite in the as-welded condition in the former material. The decrease in the impact transition temperature was largest for 1Cr0.5Mo