Why did the iron pillars in ancient India never rust?

New Delhi, the capital of India, is located in the northwest of the country, on the west bank of the Ganges tributary. It used to be an ancient capital called Delhi. Later, a new city, New Delhi, was expanded next to the ancient capital, with an area of 1.485 square kilometers and a population of 8.38 million. New Delhi is a city that combines ancient tradition with modernization. Old Delhi is like a mirror of history, showing the ancient civilization of India, while New Delhi is a milestone, showing people the progress of India.

Old Delhi has a long history. It was built around 1400 BC and was named "Indra gypsum", which means "the residence of Raytheon". Since then, Delhi has had seven cities. By the 1 century BC, Raja Diri, an Indian maharaja, rebuilt the city, hence the name Delhi. In A.D. 1648, the Mughal emperor Shah Jahan renamed Derine Bade Shah Hanjia. Delhi has a strong religious atmosphere and many ancient buildings. The Mughal Delhi Palace built with red sandstone, the Ashoka Pillar built by Ashoka of Peacock Dynasty more than 200 BC, the highest Gukutabuta in India and the largest mosque Jama Temple in India are all world-famous places of interest.

Delhi Palace is called Red Castle because its walls are made of red sandstone. Anyone who has been to Delhi will admire and visit this famous palace fortress. The whole building is octagonal with five gates, and the wall on the riverside side is as high as 30 meters, which is magnificent and magnificent. The palaces in the city are all made of marble and red sandstone. The stone pillars and walls are engraved with the relief of flower figures, and the window lattice is hollowed out with marble and inlaid with various gems, which is dazzling and magnificent. The ruins of Laobao and Ashoka Pillar built by Peacock Dynasty witnessed the vicissitudes of 2000 years. Gukutabuta was built in the13rd century, and was built by the king of Gutaibuding and the king of Iltis Mies in the Islamic slave dynasty. It has a unique style and beautiful shape. There is a mysterious atmosphere when the sunset glow shines on the tower. This tower is based on the Jem Tower in Afghanistan and was built to commemorate the victory of Islam. It is also known as the "Tower of Victory" and one of the "Seven Wonders of India". The tower is divided into five layers, the lower three layers are made of red sandstone, and the first two layers are made of white marble and red sandstone. From bottom to top, the height of each floor gradually decreases, and the vertical ridges are closely arranged, and each floor has different shapes. The first floor is 24 overlapping triangular and semi-circular columns, the second floor is semi-circular, the third floor is triangular, and the fourth and fifth floors are white marble with red sandstone. There are good ventilation and lighting facilities in the tower. Along the 379 spiral stairs, you can reach the top of the tower, overlooking the old and new Delhi City, Yam River and beautiful scenery. There is a mosque site near Kutabuta, located in the south of Delhi, in which stands a thick iron column, which is more than 7 meters high and weighs about 6 tons. This is the famous Ashoka stone pillar and one of the most precious historical relics in India. The local people said that as long as we can enclose it with iron pillars, our wish will come true. Perhaps this iron pillar really has a magical power, which makes the wisdom of modern people look weak in front of it.

Incredibly, the Ashoka Pillar has stood in the open air for more than 2000 years, experienced thousands of years of wind and rain, witnessed the replacement of emperors and princes in previous dynasties, but so far there is no trace of rust! As we all know, iron is the most easily rusted metal. Ordinary cast iron rusts in decades, not to mention hundreds or thousands of years. Until now, people are still looking for effective ways to prevent iron from rusting. Although pure iron will not rust in theory, it is very difficult to extract.

Because of its strange phenomenon, scientists all over the world are attracted to study it. In the article "Overview of Indian Archaeology", it is described as follows: "This is a forged iron handle, with an upper end diameter of 16 inch and a length of about 22 feet. The upper end of the iron column is strangely golden yellow. " This description has aroused some doubts, and many researchers believe that iron columns are made of steel. In addition, it is mentioned in the description that the inscription on the iron column is very clear, which enables people to determine its manufacturing time as 3 10.

The Stone Lion at the Top of Ashoka Pillar 19 1 1 Sir Robert hadfield took a small piece of iron from the iron pillar for inspection, and then made a detailed study of a large iron pillar sample. The results show that the iron column contains 0.08% carbon, 0.046% sulfur, 0. 1 14% phosphorus, 0.032% nitrogen, 99.72% iron, 0.034% copper and 0.034% other elements. It can be seen that the iron column is almost a fine product in the process of iron products without magazine. Judging from the purity and uniformity of iron, it is even better than carbon iron in modern Sweden. From the structural point of view, the iron column is composed of large iron particles, with only a small part of cement, which is almost invisible. In addition, there are a lot of small lines in normal shape, which seems to be related to the structure of small particles, and may be aging. Hadfield picked up a small piece of iron column and soaked it with water. It was found that the iron sheet rusted overnight, but the broken end of the iron column did not corrode under the same laboratory conditions for 4 days. Since then, a lot of analysis and research have also shown that iron column is an alloy close to pure iron, which contains carbon, silicon, phosphorus and other components besides iron, which may be the reason why it has not rusted for so many years. Does this mean that the ancient Indians have mastered the technology of smelting stainless steel and iron?

Because of this strange phenomenon, people later noticed other Millennium iron columns, such as the Great Harbin Iron Column. This iron column has three sections and was cut off in the religious chaos from 14 to 15 century. There is no inscription on the iron column, and there is not enough positive reference in other places, so there is no basis for even the most vague inference about when the iron column was made. It can only be judged from its shape that it belongs to Gupta period (320 ~ 480 AD), and it is generally believed that this iron pillar and Ashoka pillar are about the same period. The researchers studied some ironware excavated from the ancient city of Heilin. Many ironware are seriously rusted after being excavated, and continue to rust in museums unless they are specially protected. However, there is a kind of ironware with corrosion resistance and good quality, which is the ancient Xin Harless ironware in the 5th century. In addition, there are the iron pillars of knarak. This kind of iron column was once used in the collapsed black pagoda building in Knarak, and it still remains in the ruins of some protected and destroyed temples. These monasteries are believed to have been built in A.D. 1240, so the iron columns are also believed to have been cast at that time. The appearance of these iron columns is recorded in detail in the tombs of the monasteries.

These iron columns have weathered for thousands of years without decay, and the analysis shows that the composition and purity of these iron columns are almost the same. Does this mean that the ancient Indians have mastered the technology of smelting stainless steel and iron? Why didn't you find other rustless iron utensils at the same time? Why are there no records about this in ancient Indian books?

The iron pillar is still standing there, and the secret remains to be further explored and studied.