My work has a policy that when using company property, there is no expectation of privacy. Does this amount to blanket consent? This is in the state of California so unsure if this policy conflicts with state law.
Does this amount to blanket consent?
Not exactly. Instead, the policy precludes the prohibition in section 632 of the California Penal Code. The exact terms of the policy might bring up (or entail) a subtlety, but I'm answering based on the information you provide.
The California statute prohibits the recording of confidential communication [without the consent of all parties thereto]. But item (c) of that statute excludes from the definition of confidential communication those involving "any other circumstance in which the parties to the communication may reasonably expect that the communication may be overheard or recorded". In the context you mention, that circumstance could be a properly disclosed policy of no expectation of privacy.