1620
Outcome revealed that the microstructure and properties of the 17-4 stainless steel stainless steel specimens vary significantly from those produced by conventional manufacturing methods because of fine grain evolution that emerged .
 concept or principle: microstructure; concept or principle: properties; material: 17-4 stainless steel; material: steel; manufacturing process: conventional manufacturing; concept or principle: grain evolution
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: 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:
 concept or principle: microstructure; concept or principle: properties; material: 17-4 stainless steel; material: steel; manufacturing process: conventional manufacturing; concept or principle: grain evolution