Purpose
This study aims to analyze the effect of the different common post-processes on the geometrical and dimensional accuracy of selective laser melting (SLM) parts.
Design/methodology/approach
An ...artefact has been designed including cubic features formed by planar surfaces orientated according to the machine axes, covering all the X-Y area of the working space. The artefact has been analyzed both geometrically (flatness, parallelism) and dimensionally (sizes, distances) from coordinate measuring machine measurement results at three stages, namely, as-built, after sand-blasting and after stress-relieving heat treatment.
Findings
Results from the SLM machine used in this study lead to smaller parts than the nominal ones. This effect depends on the direction of the evaluated dimension of the parts, i.e. X, Y or Z direction and is differently affected by the sandblasting post-process (average erosion ratio of 68, 54 and 9 µm, respectively), being practically unaltered by the HT applied after.
Originality/value
This paper shows the influence, from a geometric and dimensional point of view, of two of the most common post-processes used after producing SLM parts, such as sand-blasting and stress-relieving heat treatment, that have not been considered in previous research.
Post weld heat treatment (PWHT) is indispensable in manufacturing process of the test blanket modules for international thermonuclear experimental reactor (ITER). Multiple PWHTs are required to ...reduce the residual stress that comes from the concentrated welded seams of the test blanket modules. As the number of treating cycles increases, considerable strength degradation of the base metal occurs. In this work, simulated stress-relieving heat treatment (SSRHT) was performed to investigate the effect of multiple PWHTs on the microstructure and tensile properties of China low activation martensitic (CLAM) steel. The results showed that its hardness decreased by 31 HV and yield strength decreased by 146 MPa for a 10-cycle treating at room temperature. The softening rate decreased and the ductility increased with increasing number of cycles at all temperatures. This phenomenon could be explained by the alterations in the martensitic lath width, volume fraction of the precipitates and the particle size. Considering the service safety of the blanket components fabricated with CLAM steel, the safety factors should be higher than 1.33, 1.29 and 1.28 for SSRHT within 10 cycles at room temperature, 450 °C and 550 °C, respectively.
