4791
The presence of δ-ferrite in 316L stainless steel powder reused several times contributes to structural defect formation in selective laser melted parts built using the pin support structure .
 316L stainless steel powder, structural defect, selective laser melted, support structure
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 316L stainless steel powder, structural defect, selective laser melted, support structure