Expert Yogi
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| The earliest combination of gold and stone cultures in the world include Badari culture, nejada culture in Egypt, elidu Obert culture in the two river basins, and bronze ware has also been found in Longshan culture and Majiayao culture sites in China. In the era of the combination of gold and stone, most areas were still at the end of the primitive society, and some areas entered the class society after the emergence of copper smelting, such as the society reflected in the negada culture of Egypt.stainless steel pipe
The bronze age was about 3000 BC to 2000 BC. Bronze is an alloy of copper and tin. Its melting point is lower than that of copper, but its hardness is higher than that of copper, so it is widely used to make utensils. After the emergence of bronzes, it promoted the development of agriculture and handicraft industry. Class society has been formed. Slavery countries have appeared in Egypt, the two river basin, India, China and the Aegean Sea. However, due to the uneven historical development of various regions, this fashion is in the primitive social stage in many regions.6 inch schedule 40 steel pipe
The iron age roughly began in the late 2000s BC and existed throughout the 1000s BC. The smelting temperature of iron is high, and the melting point is above 1500 ?, so the iron smelting technology appeared relatively late. However, iron ore has rich reserves, wide distribution, high hardness and wide application range. Therefore, it has become the most important tool after it is found. Ironware brought revolutionary changes to production. It not only promoted the rapid development of agriculture, handicraft industry and commerce, but also brought great changes to the whole society. At this time, some backward areas also entered the class society. Of course, it is still not ruled out that some areas are still in the stage of primitive society.welding carbon steel bend
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Age distribution of Metalware
