About: http://webisa.webdatacommons.org/12770699

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Mapping is normally caused by an uneven chemical reaction with the metal due to contamination such as oils, compounds, sealers or other materials left on the surface.
http://www.w3.org/ns/prov#wasQuotedFrom	ptonline.com