I am installing kubernetes cluster on bare metal. One of the Prerequisites An SSH key pair on your local linux machines. This ssh key pair is used to join the worker node with master.
Is it possible to join the kubernetes worker node to kubernetes master without enabling ssh?
That is very dependant on how both the nodes and kubernetes itself are being provisioned. Several solutions are capable of using PXE and can auto-join nodes to the cluster without requiring ssh.
As bib says, it depends.
For example, kops on AWS creates nodes that just join the cluster. The default is to have ssh enabled, but I don’t think it is needed at all for joining the cluster.
The same happens with flatcar Linux, too.
So, it is possible. It really depends on how you are provisioning your cluster 
How are you installing the Kubernetes cluster?
Nothing in Kubernetes (that I know of!) requires SSH itself. However, tools like kubespray will use it, as Ansible is based on that workflow.