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Graded material properties of stainless steel 304 were observed for wear and hardness in the direction of deposition and in Z height , due to variations in local thermal histories of the metal .
 concept or principle: material properties; material: stainless steel; concept or principle: wear; machanical property: hardness; concept or principle: deposition; concept or principle: variations; material: metal
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: material properties, stainless steel, wear, hardness, deposition, variations, metal 
Answer:
 concept or principle: material properties; material: stainless steel; concept or principle: wear; machanical property: hardness; concept or principle: deposition; concept or principle: variations; material: metal