4989
In this context , the high-speed steel showed outstanding densification behavior by SLM , even though this steel is considered to be hardly processable by SLM due to its high content of carbon and hard phase-forming elements .
 steel, densification, SLM, steel, be, SLM, carbon, elements
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:
 steel, densification, SLM, steel, be, SLM, carbon, elements