Rapid development in Information and Communications Technologies (ICT), Internet of Things (IoT), and Big Data (BD) analytics has revolutionized the manufacturing industry, which introduces the Industrial Internet of Things (IIoT) in Industry 4.0. IIoT includes machinery, manufacturing processes, and automation mechanisms. The existing IIoT system uses a centralized architecture, where the trusted third party (TTP) performs transactions, which raises security and privacy concerns and may have a single point of failure. The emerging technology Blockchain is a prominent solution to address the aforementioned issues. Motivated by these facts, in this article we highlight the issues of data dissemination in the IIoT environment and present a blockchain-based decentralized model for IIoT (DMIIoT). The proposed model uses a secure Peer-to-Peer (P2P) network, where each node interacts with other nodes. Then we highlight the potential of the DMIIoT to improve various services in IIoT, such as better production visibility and Quality of Service (QoS). Finally, we present a case study on a Smart Grid (SG) system to evaluate the efficacy of the proposed model with data load balance, energy management costs, and transmission delay parameters.