About 4,000 years ago Human beings are more advanced technology. Represents the development of the idea. Made with metal tools. The first phase of the metal smelting copper and tin, which they know is a metal used in high-temperature annealing. Later, the development of knowledge and technology that can melt steel. This requires a higher temperature to melt steel at about 4,000 years, humans, lead, copper mixed with tin alloys become fused together. To make tools and weapons of superior quality made of highly polished stone. And about 3,200 years of technological development. I think human beings find a way to bring steel, a metal that is solid and durable than bronze to make tools and weapons. With a melting temperature higher than the melting bronze. Then hit the iron while still hot into a desired shape. The steel used in tools and machinery suitable for the job that requires strength and durability.
การแปล กรุณารอสักครู่..
