The incident occurred when the workers were engaged in melting iron scraps in a boiler of the factory near Shadnagar town, police said.
The boiling iron ore liquid fell on the workers due to the explosion, the cause which is being investigated, they said.
There were about 20 workers present at the time of explosion in the factory.
The injured, who mostly hail from Uttar Pradesh and Bihar, were shifted to Osmania government hospital here.