(M777 just arrived in India was playing the blast chamber)
The artillery body tube is the crown of modern metallurgy and metal processing industry
We often say that the aero-engine is the flower of the industry, and the artillery body tube is no less difficult to manufacture than the flower of the industry. Artillery body tube in the instant of the explosion of the firing charge to withstand more than 3,000 ℃ of high temperature and high pressure of more than 800Mpa, but also after a high-speed shell rotation friction of the ravages, so the body tube must be high temperature, friction, high strength, high toughness, and to achieve such a requirement there must be a hard alloy steel, the modern mainstream artillery body tube is generally used in the carbon, nickel, chromium, molybdenum and vanadium system of alloy steel, China in the last century was blocked during the development of a series of vanadium alloy steel alternatives, and the addition of rare elements to the alloy steel of its elemental ratios and smelting and processing technology in various countries are almost top secret, visible in the development of the difficulties, on which has been ruled out 80% of the world's countries.
With the right steel, this is only the first step, processed into a body tube blank, you also have to use electroslag remelting smelting to remove phosphorus and sulfur to further improve the strength and life of the steel, this technology is also monopolized by the Five Positive and Germany, Austria, Sweden, and other countries, and the manufacturing of large-caliber artillery powerhouse highly overlap. Currently the world's largest 450-ton electroslag remelting furnace is China's Shanghai Heavy Machinery Group development and production, which also reflects to some extent why China is now able to become one of the world's strongest players in the artillery manufacturing strength.