英文關鍵字
abstract
aluminum
automobile
automotive
background
black
blue
chrome
circle
circular
closeup
construction
cutting
design
engine
engineer
engineering
equipment
exhaust
factory
heavy
industrial
industrialplant
industry
insulation
iron
line
machine
manufacturing
mechanical
metal
metallic
muffler
part
pipe
pipeline
product
production
profile
round
saw
stainless
steel
tool
tube
valve
warehouse
welding
work
workers